7:12 a.m.
Hi all ,
I was setting a two node ovirt cluster with ovirt engine on seperate node .
I completed the configuration and tested VM live migrations with out any
issues . Then for checking cluster HA I powered down one host and expected
vms running on that host to be migrated to the other one . But nothing
happened , Engine detected host as un-rechable and marked it as
non-operational and vm ran on that host went to 'unknown state' . Is that
not possible to setup a fully HA ovirt cluster with two nodes ? or else is
that my configuration problem ? please advice .
Thanks & Regards
Alex
11:11 a.m.
Hi,
Have you got power management enabled?
That's the fencing feature required for the engine to ensure that the host
is actually offline. It won't resume any other VMs to prevent potential VM
corruption (eg. VM running on multiple hosts).
Andrew.
On Jan 27, 2014 5:12 PM, "Jaison peter" <urotrip2(a)gmail.com> wrote:
Hi all ,
I was setting a two node ovirt cluster with ovirt engine on seperate node
. I completed the configuration and tested VM live migrations with out any
issues . Then for checking cluster HA I powered down one host and expected
vms running on that host to be migrated to the other one . But nothing
happened , Engine detected host as un-rechable and marked it as
non-operational and vm ran on that host went to 'unknown state' . Is that
not possible to setup a fully HA ovirt cluster with two nodes ? or else is
that my configuration problem ? please advice .
Thanks & Regards
Alex
_______________________________________________
Users mailing list
Users(a)ovirt.org
http://lists.ovirt.org/mailman/listinfo/users
12:11 p.m.
Powering off the host will never trigger vm migration.
As far as engine is concerned it just lost connection to the host, but
has no way of telling if the host is down or if a router is down.
since vm's can continue running on the host even if engine has no access
to it, starting the vm's on the second host can cause split brain and
data corruption.
The way that the engine knows what's going on is by sending heath check
queries to the vdsm.
Power management will try to reboot a host when the health checks to
vdsm will not be answered.
So... if engine gets no reply and has no way of rebooting the host, the
host status will be changed to Non-Responsive and the vm's will be
unknown because engine has no way of knowing what's happening with the
vm's.
Since reboot of the host will kill the vm's running on it - this will
never cause any vm migration but... along with the High-Availability vm
feature, you will be able to have some of the vm's re-started on the
second host after the host reboot (and that is only if Power Management
was confirmed as successful).
VM migration is only triggered when:
1. Cluster configuration states that the vm should be migrated in case
of failure
2. Engine has access to the host - so the failure is on the storage side
and not the host side.
3. the vms are not actively writing (although there might be a new RFE
for it).
hope this clears things up
Dafna
On 01/27/2014 10:11 AM, Andrew Lau wrote:
Hi,
Have you got power management enabled?
That's the fencing feature required for the engine to ensure that the
host is actually offline. It won't resume any other VMs to prevent
potential VM corruption (eg. VM running on multiple hosts).
Andrew.
On Jan 27, 2014 5:12 PM, "Jaison peter" <urotrip2(a)gmail.com
<mailto:urotrip2@gmail.com>> wrote:
Hi all ,
I was setting a two node ovirt cluster with ovirt engine on
seperate node . I completed the configuration and tested VM live
migrations with out any issues . Then for checking cluster HA I
powered down one host and expected vms running on that host to be
migrated to the other one . But nothing happened , Engine detected
host as un-rechable and marked it as non-operational and vm ran on
that host went to 'unknown state' . Is that not possible to setup
a fully HA ovirt cluster with two nodes ? or else is that my
configuration problem ? please advice .
Thanks & Regards
Alex
_______________________________________________
Users mailing list
Users(a)ovirt.org <mailto:Users@ovirt.org>
http://lists.ovirt.org/mailman/listinfo/users
_______________________________________________
Users mailing list
Users(a)ovirt.org
http://lists.ovirt.org/mailman/listinfo/users
--
Dafna Ron
12:48 p.m.
On Mon, 2014-01-27 at 11:11 +0000, Dafna Ron wrote:
Powering off the host will never trigger vm migration.
As far as engine is concerned it just lost connection to the host, but
has no way of telling if the host is down or if a router is down.
Can´t it at least check with power management if the Host status is down
first?
I mean, if the network is down there will be no response from either PM
or Host. But if PM is up and can tell you that the Host is down, sounds
rather clear cut to me...
Seems to me the VM's would be restarted sooner if the flow was altered
to first check with PM if it´s a network or Host issue, and if Host
issue, immediately restart VM's on another Host, instead of waiting for
a potentially problematic Host to boot up eventually.
/K
since vm's can continue running on the host even if engine has no
access
to it, starting the vm's on the second host can cause split brain and
data corruption.
The way that the engine knows what's going on is by sending heath check
queries to the vdsm.
Power management will try to reboot a host when the health checks to
vdsm will not be answered.
So... if engine gets no reply and has no way of rebooting the host, the
host status will be changed to Non-Responsive and the vm's will be
unknown because engine has no way of knowing what's happening with the
vm's.
Since reboot of the host will kill the vm's running on it - this will
never cause any vm migration but... along with the High-Availability vm
feature, you will be able to have some of the vm's re-started on the
second host after the host reboot (and that is only if Power Management
was confirmed as successful).
VM migration is only triggered when:
1. Cluster configuration states that the vm should be migrated in case
of failure
2. Engine has access to the host - so the failure is on the storage side
and not the host side.
3. the vms are not actively writing (although there might be a new RFE
for it).
hope this clears things up
Dafna
On 01/27/2014 10:11 AM, Andrew Lau wrote:
>
> Hi,
>
> Have you got power management enabled?
>
> That's the fencing feature required for the engine to ensure that the
> host is actually offline. It won't resume any other VMs to prevent
> potential VM corruption (eg. VM running on multiple hosts).
>
> Andrew.
>
> On Jan 27, 2014 5:12 PM, "Jaison peter" <urotrip2(a)gmail.com
> <mailto:urotrip2@gmail.com>> wrote:
>
> Hi all ,
>
> I was setting a two node ovirt cluster with ovirt engine on
> seperate node . I completed the configuration and tested VM live
> migrations with out any issues . Then for checking cluster HA I
> powered down one host and expected vms running on that host to be
> migrated to the other one . But nothing happened , Engine detected
> host as un-rechable and marked it as non-operational and vm ran on
> that host went to 'unknown state' . Is that not possible to setup
> a fully HA ovirt cluster with two nodes ? or else is that my
> configuration problem ? please advice .
>
> Thanks & Regards
>
> Alex
>
> _______________________________________________
> Users mailing list
> Users(a)ovirt.org <mailto:Users@ovirt.org>
> http://lists.ovirt.org/mailman/listinfo/users
>
>
>
> _______________________________________________
> Users mailing list
> Users(a)ovirt.org
> http://lists.ovirt.org/mailman/listinfo/users
--
Dafna Ron
_______________________________________________
Users mailing list
Users(a)ovirt.org
http://lists.ovirt.org/mailman/listinfo/users
--
Med Vänliga Hälsningar
-------------------------------------------------------------------------------
Karli Sjöberg
Swedish University of Agricultural Sciences Box 7079 (Visiting Address
Kronåsvägen 8)
S-750 07 Uppsala, Sweden
Phone: +46-(0)18-67 15 66
karli.sjoberg(a)slu.se
1:05 p.m.
I am adding Tareq for the Power Management implementation.
Dafna
On 01/27/2014 11:48 AM, Karli Sjöberg wrote:
On Mon, 2014-01-27 at 11:11 +0000, Dafna Ron wrote:
> Powering off the host will never trigger vm migration.
> As far as engine is concerned it just lost connection to the host, but
> has no way of telling if the host is down or if a router is down.
Can´t it at least check with power management if the Host status is down
first?
I mean, if the network is down there will be no response from either PM
or Host. But if PM is up and can tell you that the Host is down, sounds
rather clear cut to me...
Seems to me the VM's would be restarted sooner if the flow was altered
to first check with PM if it´s a network or Host issue, and if Host
issue, immediately restart VM's on another Host, instead of waiting for
a potentially problematic Host to boot up eventually.
/K
> since vm's can continue running on the host even if engine has no access
> to it, starting the vm's on the second host can cause split brain and
> data corruption.
>
> The way that the engine knows what's going on is by sending heath check
> queries to the vdsm.
> Power management will try to reboot a host when the health checks to
> vdsm will not be answered.
> So... if engine gets no reply and has no way of rebooting the host, the
> host status will be changed to Non-Responsive and the vm's will be
> unknown because engine has no way of knowing what's happening with the
> vm's.
> Since reboot of the host will kill the vm's running on it - this will
> never cause any vm migration but... along with the High-Availability vm
> feature, you will be able to have some of the vm's re-started on the
> second host after the host reboot (and that is only if Power Management
> was confirmed as successful).
>
> VM migration is only triggered when:
> 1. Cluster configuration states that the vm should be migrated in case
> of failure
> 2. Engine has access to the host - so the failure is on the storage side
> and not the host side.
> 3. the vms are not actively writing (although there might be a new RFE
> for it).
>
> hope this clears things up
>
> Dafna
>
>
>
> On 01/27/2014 10:11 AM, Andrew Lau wrote:
>> Hi,
>>
>> Have you got power management enabled?
>>
>> That's the fencing feature required for the engine to ensure that the
>> host is actually offline. It won't resume any other VMs to prevent
>> potential VM corruption (eg. VM running on multiple hosts).
>>
>> Andrew.
>>
>> On Jan 27, 2014 5:12 PM, "Jaison peter" <urotrip2(a)gmail.com
>> <mailto:urotrip2@gmail.com>> wrote:
>>
>> Hi all ,
>>
>> I was setting a two node ovirt cluster with ovirt engine on
>> seperate node . I completed the configuration and tested VM live
>> migrations with out any issues . Then for checking cluster HA I
>> powered down one host and expected vms running on that host to be
>> migrated to the other one . But nothing happened , Engine detected
>> host as un-rechable and marked it as non-operational and vm ran on
>> that host went to 'unknown state' . Is that not possible to setup
>> a fully HA ovirt cluster with two nodes ? or else is that my
>> configuration problem ? please advice .
>>
>> Thanks & Regards
>>
>> Alex
>>
>> _______________________________________________
>> Users mailing list
>> Users(a)ovirt.org <mailto:Users@ovirt.org>
>> http://lists.ovirt.org/mailman/listinfo/users
>>
>>
>>
>> _______________________________________________
>> Users mailing list
>> Users(a)ovirt.org
>> http://lists.ovirt.org/mailman/listinfo/users
>
> --
> Dafna Ron
> _______________________________________________
> Users mailing list
> Users(a)ovirt.org
> http://lists.ovirt.org/mailman/listinfo/users
--
Dafna Ron
1:43 p.m.
Hi,
Power management makes use of special *dedicated* hardware in order to
restart hosts independently of host OS. The engine connects to a power
management devices using a *dedicated* network IP address.
The engine is capable of rebooting hosts that have entered a
non-operational or non-responsive state,
The abilities provided by all power management devices are: check
status, start, stop and recycle (restart)...
In the case of non-responsive host: all of the VMs that are currently
running on that host can also become non-responsive. However, the
non-responsive host keeps locking the VM hard disk for all VMs it is
running. Attempting to start a VM on a different host and assign the
second host write privileges for the virtual machine hard disk image can
cause data corruption.
Rebooting allows the engine to assume that the lock on a VM hard disk
image has been released.
The engine can know for sure that the problematic host has been rebooted
via the power management device and then it can start a VM from the
problematic host on another host without risking data corruption.
Important note: A virtual machine that has been marked highly-available
can not be safely started on a different host without the certainty that
doing so will not cause data corruption.
N-joy,
--Tareq
On 01/27/2014 02:05 PM, Dafna Ron wrote:
I am adding Tareq for the Power Management implementation.
Dafna
On 01/27/2014 11:48 AM, Karli Sjöberg wrote:
> On Mon, 2014-01-27 at 11:11 +0000, Dafna Ron wrote:
>> Powering off the host will never trigger vm migration.
>> As far as engine is concerned it just lost connection to the host, but
>> has no way of telling if the host is down or if a router is down.
> Can´t it at least check with power management if the Host status is down
> first?
>
> I mean, if the network is down there will be no response from either PM
> or Host. But if PM is up and can tell you that the Host is down, sounds
> rather clear cut to me...
>
> Seems to me the VM's would be restarted sooner if the flow was altered
> to first check with PM if it´s a network or Host issue, and if Host
> issue, immediately restart VM's on another Host, instead of waiting for
> a potentially problematic Host to boot up eventually.
>
> /K
>
>> since vm's can continue running on the host even if engine has no
>> access
>> to it, starting the vm's on the second host can cause split brain and
>> data corruption.
>>
>> The way that the engine knows what's going on is by sending heath check
>> queries to the vdsm.
>> Power management will try to reboot a host when the health checks to
>> vdsm will not be answered.
>> So... if engine gets no reply and has no way of rebooting the host, the
>> host status will be changed to Non-Responsive and the vm's will be
>> unknown because engine has no way of knowing what's happening with the
>> vm's.
>> Since reboot of the host will kill the vm's running on it - this will
>> never cause any vm migration but... along with the High-Availability vm
>> feature, you will be able to have some of the vm's re-started on the
>> second host after the host reboot (and that is only if Power Management
>> was confirmed as successful).
>>
>> VM migration is only triggered when:
>> 1. Cluster configuration states that the vm should be migrated in case
>> of failure
>> 2. Engine has access to the host - so the failure is on the storage
>> side
>> and not the host side.
>> 3. the vms are not actively writing (although there might be a new RFE
>> for it).
>>
>> hope this clears things up
>>
>> Dafna
>>
>>
>>
>> On 01/27/2014 10:11 AM, Andrew Lau wrote:
>>> Hi,
>>>
>>> Have you got power management enabled?
>>>
>>> That's the fencing feature required for the engine to ensure that the
>>> host is actually offline. It won't resume any other VMs to prevent
>>> potential VM corruption (eg. VM running on multiple hosts).
>>>
>>> Andrew.
>>>
>>> On Jan 27, 2014 5:12 PM, "Jaison peter" <urotrip2(a)gmail.com
>>> <mailto:urotrip2@gmail.com>> wrote:
>>>
>>> Hi all ,
>>>
>>> I was setting a two node ovirt cluster with ovirt engine on
>>> seperate node . I completed the configuration and tested VM live
>>> migrations with out any issues . Then for checking cluster HA I
>>> powered down one host and expected vms running on that host to be
>>> migrated to the other one . But nothing happened , Engine
>>> detected
>>> host as un-rechable and marked it as non-operational and vm
>>> ran on
>>> that host went to 'unknown state' . Is that not possible to
setup
>>> a fully HA ovirt cluster with two nodes ? or else is that my
>>> configuration problem ? please advice .
>>>
>>> Thanks & Regards
>>>
>>> Alex
>>>
>>> _______________________________________________
>>> Users mailing list
>>> Users(a)ovirt.org <mailto:Users@ovirt.org>
>>> http://lists.ovirt.org/mailman/listinfo/users
>>>
>>>
>>>
>>> _______________________________________________
>>> Users mailing list
>>> Users(a)ovirt.org
>>> http://lists.ovirt.org/mailman/listinfo/users
>>
>> --
>> Dafna Ron
>> _______________________________________________
>> Users mailing list
>> Users(a)ovirt.org
>> http://lists.ovirt.org/mailman/listinfo/users
>
>
1:50 p.m.
Hi,
I think he was asking what if the power management device reported that the
host was powered off. Then VMs should be brought back up as being off would
essentially be the same as running a power cycle/reboot?
Another example I'm seeing is what happens if the whole host loses power
and it's power management device then becomes unavailable (ie. not
reachable) then you're stuck in the case where it requires manual
intervention.
I would be interested to potentially see something like a timeout on those
problematic VMs (eg. if nothing was read or write after x amount of time)
then you could consider the host as offline? I guess then that adds a lot
of risk..
On Mon, Jan 27, 2014 at 11:43 PM, Tareq Alayan <talayan(a)redhat.com> wrote:
Hi,
Power management makes use of special *dedicated* hardware in order to
restart hosts independently of host OS. The engine connects to a power
management devices using a *dedicated* network IP address.
The engine is capable of rebooting hosts that have entered a
non-operational or non-responsive state,
The abilities provided by all power management devices are: check status,
start, stop and recycle (restart)...
In the case of non-responsive host: all of the VMs that are currently
running on that host can also become non-responsive. However, the
non-responsive host keeps locking the VM hard disk for all VMs it is
running. Attempting to start a VM on a different host and assign the second
host write privileges for the virtual machine hard disk image can cause
data corruption.
Rebooting allows the engine to assume that the lock on a VM hard disk
image has been released.
The engine can know for sure that the problematic host has been rebooted
via the power management device and then it can start a VM from the
problematic host on another host without risking data corruption.
Important note: A virtual machine that has been marked highly-available
can not be safely started on a different host without the certainty that
doing so will not cause data corruption.
N-joy,
--Tareq
On 01/27/2014 02:05 PM, Dafna Ron wrote:
> I am adding Tareq for the Power Management implementation.
>
> Dafna
>
>
> On 01/27/2014 11:48 AM, Karli Sjöberg wrote:
>
>> On Mon, 2014-01-27 at 11:11 +0000, Dafna Ron wrote:
>>
>>> Powering off the host will never trigger vm migration.
>>> As far as engine is concerned it just lost connection to the host, but
>>> has no way of telling if the host is down or if a router is down.
>>>
>> Can´t it at least check with power management if the Host status is down
>> first?
>>
>> I mean, if the network is down there will be no response from either PM
>> or Host. But if PM is up and can tell you that the Host is down, sounds
>> rather clear cut to me...
>>
>> Seems to me the VM's would be restarted sooner if the flow was altered
>> to first check with PM if it´s a network or Host issue, and if Host
>> issue, immediately restart VM's on another Host, instead of waiting for
>> a potentially problematic Host to boot up eventually.
>>
>> /K
>>
>> since vm's can continue running on the host even if engine has no access
>>> to it, starting the vm's on the second host can cause split brain and
>>> data corruption.
>>>
>>> The way that the engine knows what's going on is by sending heath check
>>> queries to the vdsm.
>>> Power management will try to reboot a host when the health checks to
>>> vdsm will not be answered.
>>> So... if engine gets no reply and has no way of rebooting the host, the
>>> host status will be changed to Non-Responsive and the vm's will be
>>> unknown because engine has no way of knowing what's happening with the
>>> vm's.
>>> Since reboot of the host will kill the vm's running on it - this will
>>> never cause any vm migration but... along with the High-Availability vm
>>> feature, you will be able to have some of the vm's re-started on the
>>> second host after the host reboot (and that is only if Power Management
>>> was confirmed as successful).
>>>
>>> VM migration is only triggered when:
>>> 1. Cluster configuration states that the vm should be migrated in case
>>> of failure
>>> 2. Engine has access to the host - so the failure is on the storage side
>>> and not the host side.
>>> 3. the vms are not actively writing (although there might be a new RFE
>>> for it).
>>>
>>> hope this clears things up
>>>
>>> Dafna
>>>
>>>
>>>
>>> On 01/27/2014 10:11 AM, Andrew Lau wrote:
>>>
>>>> Hi,
>>>>
>>>> Have you got power management enabled?
>>>>
>>>> That's the fencing feature required for the engine to ensure that
the
>>>> host is actually offline. It won't resume any other VMs to prevent
>>>> potential VM corruption (eg. VM running on multiple hosts).
>>>>
>>>> Andrew.
>>>>
>>>> On Jan 27, 2014 5:12 PM, "Jaison peter" <urotrip2(a)gmail.com
>>>> <mailto:urotrip2@gmail.com>> wrote:
>>>>
>>>> Hi all ,
>>>>
>>>> I was setting a two node ovirt cluster with ovirt engine on
>>>> seperate node . I completed the configuration and tested VM live
>>>> migrations with out any issues . Then for checking cluster HA I
>>>> powered down one host and expected vms running on that host to be
>>>> migrated to the other one . But nothing happened , Engine detected
>>>> host as un-rechable and marked it as non-operational and vm ran on
>>>> that host went to 'unknown state' . Is that not possible to
setup
>>>> a fully HA ovirt cluster with two nodes ? or else is that my
>>>> configuration problem ? please advice .
>>>>
>>>> Thanks & Regards
>>>>
>>>> Alex
>>>>
>>>> _______________________________________________
>>>> Users mailing list
>>>> Users(a)ovirt.org <mailto:Users@ovirt.org>
>>>> http://lists.ovirt.org/mailman/listinfo/users
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> Users mailing list
>>>> Users(a)ovirt.org
>>>> http://lists.ovirt.org/mailman/listinfo/users
>>>>
>>>
>>> --
>>> Dafna Ron
>>> _______________________________________________
>>> Users mailing list
>>> Users(a)ovirt.org
>>> http://lists.ovirt.org/mailman/listinfo/users
>>>
>>
>>
>>
>
>
1:54 p.m.
On Mon, 2014-01-27 at 14:43 +0200, Tareq Alayan wrote:
Hi,
Power management makes use of special *dedicated* hardware in order to
restart hosts independently of host OS. The engine connects to a power
management devices using a *dedicated* network IP address.
The engine is capable of rebooting hosts that have entered a
non-operational or non-responsive state,
The abilities provided by all power management devices are: check
status, start, stop and recycle (restart)...
In the case of non-responsive host: all of the VMs that are currently
running on that host can also become non-responsive. However, the
non-responsive host keeps locking the VM hard disk for all VMs it is
running. Attempting to start a VM on a different host and assign the
second host write privileges for the virtual machine hard disk image can
cause data corruption.
Exactly! If Engine was to first check towards the power management that
the problematic/non-responsove Host indeed is down, there would be no
risk of data corruption.
That´s why I suggested a change in the HA flow to first check if the
Host is indeed down, if so, just start the VM's on another Host.
/K
Rebooting allows the engine to assume that the lock on a VM hard disk
image has been released.
The engine can know for sure that the problematic host has been rebooted
via the power management device and then it can start a VM from the
problematic host on another host without risking data corruption.
Important note: A virtual machine that has been marked highly-available
can not be safely started on a different host without the certainty that
doing so will not cause data corruption.
N-joy,
--Tareq
On 01/27/2014 02:05 PM, Dafna Ron wrote:
> I am adding Tareq for the Power Management implementation.
>
> Dafna
>
>
> On 01/27/2014 11:48 AM, Karli Sjöberg wrote:
>> On Mon, 2014-01-27 at 11:11 +0000, Dafna Ron wrote:
>>> Powering off the host will never trigger vm migration.
>>> As far as engine is concerned it just lost connection to the host, but
>>> has no way of telling if the host is down or if a router is down.
>> Can´t it at least check with power management if the Host status is down
>> first?
>>
>> I mean, if the network is down there will be no response from either PM
>> or Host. But if PM is up and can tell you that the Host is down, sounds
>> rather clear cut to me...
>>
>> Seems to me the VM's would be restarted sooner if the flow was altered
>> to first check with PM if it´s a network or Host issue, and if Host
>> issue, immediately restart VM's on another Host, instead of waiting for
>> a potentially problematic Host to boot up eventually.
>>
>> /K
>>
>>> since vm's can continue running on the host even if engine has no
>>> access
>>> to it, starting the vm's on the second host can cause split brain and
>>> data corruption.
>>>
>>> The way that the engine knows what's going on is by sending heath check
>>> queries to the vdsm.
>>> Power management will try to reboot a host when the health checks to
>>> vdsm will not be answered.
>>> So... if engine gets no reply and has no way of rebooting the host, the
>>> host status will be changed to Non-Responsive and the vm's will be
>>> unknown because engine has no way of knowing what's happening with the
>>> vm's.
>>> Since reboot of the host will kill the vm's running on it - this will
>>> never cause any vm migration but... along with the High-Availability vm
>>> feature, you will be able to have some of the vm's re-started on the
>>> second host after the host reboot (and that is only if Power Management
>>> was confirmed as successful).
>>>
>>> VM migration is only triggered when:
>>> 1. Cluster configuration states that the vm should be migrated in case
>>> of failure
>>> 2. Engine has access to the host - so the failure is on the storage
>>> side
>>> and not the host side.
>>> 3. the vms are not actively writing (although there might be a new RFE
>>> for it).
>>>
>>> hope this clears things up
>>>
>>> Dafna
>>>
>>>
>>>
>>> On 01/27/2014 10:11 AM, Andrew Lau wrote:
>>>> Hi,
>>>>
>>>> Have you got power management enabled?
>>>>
>>>> That's the fencing feature required for the engine to ensure that
the
>>>> host is actually offline. It won't resume any other VMs to prevent
>>>> potential VM corruption (eg. VM running on multiple hosts).
>>>>
>>>> Andrew.
>>>>
>>>> On Jan 27, 2014 5:12 PM, "Jaison peter"
<urotrip2(a)gmail.com
>>>> <mailto:urotrip2@gmail.com>> wrote:
>>>>
>>>> Hi all ,
>>>>
>>>> I was setting a two node ovirt cluster with ovirt engine on
>>>> seperate node . I completed the configuration and tested VM live
>>>> migrations with out any issues . Then for checking cluster HA I
>>>> powered down one host and expected vms running on that host to be
>>>> migrated to the other one . But nothing happened , Engine
>>>> detected
>>>> host as un-rechable and marked it as non-operational and vm
>>>> ran on
>>>> that host went to 'unknown state' . Is that not possible to
setup
>>>> a fully HA ovirt cluster with two nodes ? or else is that my
>>>> configuration problem ? please advice .
>>>>
>>>> Thanks & Regards
>>>>
>>>> Alex
>>>>
>>>> _______________________________________________
>>>> Users mailing list
>>>> Users(a)ovirt.org <mailto:Users@ovirt.org>
>>>> http://lists.ovirt.org/mailman/listinfo/users
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> Users mailing list
>>>> Users(a)ovirt.org
>>>> http://lists.ovirt.org/mailman/listinfo/users
>>>
>>> --
>>> Dafna Ron
>>> _______________________________________________
>>> Users mailing list
>>> Users(a)ovirt.org
>>> http://lists.ovirt.org/mailman/listinfo/users
>>
>>
>
>
--
Med Vänliga Hälsningar
-------------------------------------------------------------------------------
Karli Sjöberg
Swedish University of Agricultural Sciences Box 7079 (Visiting Address
Kronåsvägen 8)
S-750 07 Uppsala, Sweden
Phone: +46-(0)18-67 15 66
karli.sjoberg(a)slu.se
1:59 p.m.
This is a multi-part message in MIME format.
--------------020302000209030903080908
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Content-Transfer-Encoding: 8bit
Adding Eli.
On 01/27/2014 02:50 PM, Andrew Lau wrote:
Hi,
I think he was asking what if the power management device reported
that the host was powered off. Then VMs should be brought back up as
being off would essentially be the same as running a power cycle/reboot?
Another example I'm seeing is what happens if the whole host loses
power and it's power management device then becomes unavailable (ie.
not reachable) then you're stuck in the case where it requires manual
intervention.
I would be interested to potentially see something like a timeout on
those problematic VMs (eg. if nothing was read or write after x amount
of time) then you could consider the host as offline? I guess then
that adds a lot of risk..
On Mon, Jan 27, 2014 at 11:43 PM, Tareq Alayan <talayan(a)redhat.com
<mailto:talayan@redhat.com>> wrote:
Hi,
Power management makes use of special *dedicated* hardware in
order to restart hosts independently of host OS. The engine
connects to a power management devices using a *dedicated* network
IP address.
The engine is capable of rebooting hosts that have entered a
non-operational or non-responsive state,
The abilities provided by all power management devices are: check
status, start, stop and recycle (restart)...
In the case of non-responsive host: all of the VMs that are
currently running on that host can also become non-responsive.
However, the non-responsive host keeps locking the VM hard disk
for all VMs it is running. Attempting to start a VM on a different
host and assign the second host write privileges for the virtual
machine hard disk image can cause data corruption.
Rebooting allows the engine to assume that the lock on a VM hard
disk image has been released.
The engine can know for sure that the problematic host has been
rebooted via the power management device and then it can start a
VM from the problematic host on another host without risking data
corruption.
Important note: A virtual machine that has been marked
highly-available can not be safely started on a different host
without the certainty that doing so will not cause data corruption.
N-joy,
--Tareq
On 01/27/2014 02:05 PM, Dafna Ron wrote:
I am adding Tareq for the Power Management implementation.
Dafna
On 01/27/2014 11:48 AM, Karli Sjöberg wrote:
On Mon, 2014-01-27 at 11:11 +0000, Dafna Ron wrote:
Powering off the host will never trigger vm migration.
As far as engine is concerned it just lost connection
to the host, but
has no way of telling if the host is down or if a
router is down.
CanŽt it at least check with power management if the Host
status is down
first?
I mean, if the network is down there will be no response
from either PM
or Host. But if PM is up and can tell you that the Host is
down, sounds
rather clear cut to me...
Seems to me the VM's would be restarted sooner if the flow
was altered
to first check with PM if itŽs a network or Host issue,
and if Host
issue, immediately restart VM's on another Host, instead
of waiting for
a potentially problematic Host to boot up eventually.
/K
since vm's can continue running on the host even if
engine has no access
to it, starting the vm's on the second host can cause
split brain and
data corruption.
The way that the engine knows what's going on is by
sending heath check
queries to the vdsm.
Power management will try to reboot a host when the
health checks to
vdsm will not be answered.
So... if engine gets no reply and has no way of
rebooting the host, the
host status will be changed to Non-Responsive and the
vm's will be
unknown because engine has no way of knowing what's
happening with the
vm's.
Since reboot of the host will kill the vm's running on
it - this will
never cause any vm migration but... along with the
High-Availability vm
feature, you will be able to have some of the vm's
re-started on the
second host after the host reboot (and that is only if
Power Management
was confirmed as successful).
VM migration is only triggered when:
1. Cluster configuration states that the vm should be
migrated in case
of failure
2. Engine has access to the host - so the failure is
on the storage side
and not the host side.
3. the vms are not actively writing (although there
might be a new RFE
for it).
hope this clears things up
Dafna
On 01/27/2014 10:11 AM, Andrew Lau wrote:
Hi,
Have you got power management enabled?
That's the fencing feature required for the engine
to ensure that the
host is actually offline. It won't resume any
other VMs to prevent
potential VM corruption (eg. VM running on
multiple hosts).
Andrew.
On Jan 27, 2014 5:12 PM, "Jaison peter"
<urotrip2(a)gmail.com <mailto:urotrip2@gmail.com>
<mailto:urotrip2@gmail.com
<mailto:urotrip2@gmail.com>>> wrote:
Hi all ,
I was setting a two node ovirt cluster with
ovirt engine on
seperate node . I completed the configuration
and tested VM live
migrations with out any issues . Then for
checking cluster HA I
powered down one host and expected vms
running on that host to be
migrated to the other one . But nothing
happened , Engine detected
host as un-rechable and marked it as
non-operational and vm ran on
that host went to 'unknown state' . Is that
not possible to setup
a fully HA ovirt cluster with two nodes ? or
else is that my
configuration problem ? please advice .
Thanks & Regards
Alex
_______________________________________________
Users mailing list
Users(a)ovirt.org <mailto:Users@ovirt.org>
<mailto:Users@ovirt.org <mailto:Users@ovirt.org>>
http://lists.ovirt.org/mailman/listinfo/users
_______________________________________________
Users mailing list
Users(a)ovirt.org <mailto:Users@ovirt.org>
http://lists.ovirt.org/mailman/listinfo/users
--
Dafna Ron
_______________________________________________
Users mailing list
Users(a)ovirt.org <mailto:Users@ovirt.org>
http://lists.ovirt.org/mailman/listinfo/users
--------------020302000209030903080908
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<head>
<meta content="text/html; charset=ISO-8859-1"
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</head>
<body bgcolor="#FFFFFF" text="#000000">
Adding Eli.<br>
<br>
<br>
<div class="moz-cite-prefix">On 01/27/2014 02:50 PM, Andrew Lau
wrote:<br>
</div>
<blockquote
cite="mid:CAD7dF9fNhvSsd+Oj2s+rJo4oSkwnZiU6H23tbY0XL12_JShfsw@mail.gmail.com"
type="cite">
<div dir="ltr">
<div class="gmail_default"
style="font-family:tahoma,sans-serif">Hi,</div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif"><br>
</div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif">
I think he was asking what if the power management device
reported that the host was powered off. Then VMs should be
brought back up as being off would essentially be the same as
running a power cycle/reboot?</div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif">
<br>
</div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif">Another
example I'm seeing is what happens if the whole host loses
power and it's power management device then becomes
unavailable (ie. not reachable) then you're stuck in the case
where it requires manual intervention. </div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif"><br>
</div>
<div class="gmail_default"
style="font-family:tahoma,sans-serif">I
would be interested to potentially see something like a
timeout on those problematic VMs (eg. if nothing was read or
write after x amount of time) then you could consider the host
as offline? I guess then that adds a lot of risk..</div>
<div class="gmail_extra">
<br>
<br>
<div class="gmail_quote">On Mon, Jan 27, 2014 at 11:43 PM,
Tareq Alayan <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:talayan@redhat.com"
target="_blank">talayan(a)redhat.com</a>&gt;</span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi,<br>
<br>
Power management makes use of special *dedicated* hardware
in order to restart hosts independently of host OS. The
engine connects to a power management devices using a
*dedicated* network IP address.<br>
The engine is capable of rebooting hosts that have entered
a non-operational or non-responsive state,<br>
The abilities provided by all power management devices
are: check status, start, stop and recycle (restart)...<br>
<br>
In the case of non-responsive host: all of the VMs that
are currently running on that host can also become
non-responsive. However, the non-responsive host keeps
locking the VM hard disk for all VMs it is running.
Attempting to start a VM on a different host and assign
the second host write privileges for the virtual machine
hard disk image can cause data corruption.<br>
Rebooting allows the engine to assume that the lock on a
VM hard disk image has been released.<br>
The engine can know for sure that the problematic host has
been rebooted via the power management device and then it
can start a VM from the problematic host on another host
without risking data corruption.<br>
Important note: A virtual machine that has been marked
highly-available can not be safely started on a different
host without the certainty that doing so will not cause
data corruption.<br>
<br>
N-joy,<br>
<br>
--Tareq
<div class="HOEnZb">
<div class="h5"><br>
<br>
<br>
<br>
On 01/27/2014 02:05 PM, Dafna Ron wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
I am adding Tareq for the Power Management
implementation.<br>
<br>
Dafna<br>
<br>
<br>
On 01/27/2014 11:48 AM, Karli Sjöberg wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
On Mon, 2014-01-27 at 11:11 +0000, Dafna Ron
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0
0 .8ex;border-left:1px #ccc
solid;padding-left:1ex">
Powering off the host will never trigger vm
migration.<br>
As far as engine is concerned it just lost
connection to the host, but<br>
has no way of telling if the host is down or if
a router is down.<br>
</blockquote>
Can´t it at least check with power management if
the Host status is down<br>
first?<br>
<br>
I mean, if the network is down there will be no
response from either PM<br>
or Host. But if PM is up and can tell you that the
Host is down, sounds<br>
rather clear cut to me...<br>
<br>
Seems to me the VM's would be restarted sooner if
the flow was altered<br>
to first check with PM if it´s a network or Host
issue, and if Host<br>
issue, immediately restart VM's on another Host,
instead of waiting for<br>
a potentially problematic Host to boot up
eventually.<br>
<br>
/K<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0
0 .8ex;border-left:1px #ccc
solid;padding-left:1ex">
since vm's can continue running on the host even
if engine has no access<br>
to it, starting the vm's on the second host can
cause split brain and<br>
data corruption.<br>
<br>
The way that the engine knows what's going on is
by sending heath check<br>
queries to the vdsm.<br>
Power management will try to reboot a host when
the health checks to<br>
vdsm will not be answered.<br>
So... if engine gets no reply and has no way of
rebooting the host, the<br>
host status will be changed to Non-Responsive
and the vm's will be<br>
unknown because engine has no way of knowing
what's happening with the<br>
vm's.<br>
Since reboot of the host will kill the vm's
running on it - this will<br>
never cause any vm migration but... along with
the High-Availability vm<br>
feature, you will be able to have some of the
vm's re-started on the<br>
second host after the host reboot (and that is
only if Power Management<br>
was confirmed as successful).<br>
<br>
VM migration is only triggered when:<br>
1. Cluster configuration states that the vm
should be migrated in case<br>
of failure<br>
2. Engine has access to the host - so the
failure is on the storage side<br>
and not the host side.<br>
3. the vms are not actively writing (although
there might be a new RFE<br>
for it).<br>
<br>
hope this clears things up<br>
<br>
Dafna<br>
<br>
<br>
<br>
On 01/27/2014 10:11 AM, Andrew Lau wrote:<br>
<blockquote class="gmail_quote" style="margin:0
0 0 .8ex;border-left:1px #ccc
solid;padding-left:1ex">
Hi,<br>
<br>
Have you got power management enabled?<br>
<br>
That's the fencing feature required for the
engine to ensure that the<br>
host is actually offline. It won't resume any
other VMs to prevent<br>
potential VM corruption (eg. VM running on
multiple hosts).<br>
<br>
Andrew.<br>
<br>
On Jan 27, 2014 5:12 PM, "Jaison peter" <<a
moz-do-not-send="true"
href="mailto:urotrip2@gmail.com"
target="_blank">urotrip2(a)gmail.com</a><br>
<mailto:<a moz-do-not-send="true"
href="mailto:urotrip2@gmail.com"
target="_blank">urotrip2(a)gmail.com</a>&gt;&gt;
wrote:<br>
<br>
Hi all ,<br>
<br>
I was setting a two node ovirt
cluster
with ovirt engine on<br>
seperate node . I completed the
configuration and tested VM live<br>
migrations with out any issues .
Then for
checking cluster HA I<br>
powered down one host and
expected vms
running on that host to be<br>
migrated to the other one . But
nothing
happened , Engine detected<br>
host as un-rechable and marked
it as
non-operational and vm ran on<br>
that host went to 'unknown
state' . Is
that not possible to setup<br>
a fully HA ovirt cluster with
two nodes ?
or else is that my<br>
configuration problem ? please
advice .<br>
<br>
Thanks &
Regards<br>
<br>
Alex<br>
<br>
_______________________________________________<br>
Users mailing list<br>
<a
moz-do-not-send="true"
href="mailto:Users@ovirt.org"
target="_blank">Users(a)ovirt.org</a>
<mailto:<a moz-do-not-send="true"
href="mailto:Users@ovirt.org"
target="_blank">Users(a)ovirt.org</a>&gt;<br>
<a
moz-do-not-send="true"
href="http://lists.ovirt.org/mailman/listinfo/users"
target="_blank">http://lists.ovirt.org/mailman/listinfo/user...
<br>
<br>
<br>
_______________________________________________<br>
Users mailing list<br>
<a moz-do-not-send="true"
href="mailto:Users@ovirt.org"
target="_blank">Users(a)ovirt.org</a><br>
<a moz-do-not-send="true"
href="http://lists.ovirt.org/mailman/listinfo/users"
target="_blank">http://lists.ovirt.org/mailman/listinfo/user...
</blockquote>
<br>
-- <br>
Dafna Ron<br>
_______________________________________________<br>
Users mailing list<br>
<a moz-do-not-send="true"
href="mailto:Users@ovirt.org"
target="_blank">Users(a)ovirt.org</a><br>
<a moz-do-not-send="true"
href="http://lists.ovirt.org/mailman/listinfo/users"
target="_blank">http://lists.ovirt.org/mailman/listinfo/user...
</blockquote>
<br>
<br>
</blockquote>
<br>
<br>
</blockquote>
<br>
</div>
</div>
</blockquote>
</div>
<br>
</div>
</div>
</blockquote>
<br>
</body>
</html>
--------------020302000209030903080908--
2:02 p.m.
Andrew,
Once this discussion is finished, and If what you like done is not in
the current implementation can you please open a bug/feature request for
it?
Thanks,
Dafna
On 01/27/2014 12:59 PM, Tareq Alayan wrote:
Adding Eli.
On 01/27/2014 02:50 PM, Andrew Lau wrote:
> Hi,
>
> I think he was asking what if the power management device reported
> that the host was powered off. Then VMs should be brought back up as
> being off would essentially be the same as running a power cycle/reboot?
>
> Another example I'm seeing is what happens if the whole host loses
> power and it's power management device then becomes unavailable (ie.
> not reachable) then you're stuck in the case where it requires manual
> intervention.
>
> I would be interested to potentially see something like a timeout on
> those problematic VMs (eg. if nothing was read or write after x
> amount of time) then you could consider the host as offline? I guess
> then that adds a lot of risk..
>
>
> On Mon, Jan 27, 2014 at 11:43 PM, Tareq Alayan <talayan(a)redhat.com
> <mailto:talayan@redhat.com>> wrote:
>
> Hi,
>
> Power management makes use of special *dedicated* hardware in
> order to restart hosts independently of host OS. The engine
> connects to a power management devices using a *dedicated*
> network IP address.
> The engine is capable of rebooting hosts that have entered a
> non-operational or non-responsive state,
> The abilities provided by all power management devices are: check
> status, start, stop and recycle (restart)...
>
> In the case of non-responsive host: all of the VMs that are
> currently running on that host can also become non-responsive.
> However, the non-responsive host keeps locking the VM hard disk
> for all VMs it is running. Attempting to start a VM on a
> different host and assign the second host write privileges for
> the virtual machine hard disk image can cause data corruption.
> Rebooting allows the engine to assume that the lock on a VM hard
> disk image has been released.
> The engine can know for sure that the problematic host has been
> rebooted via the power management device and then it can start a
> VM from the problematic host on another host without risking data
> corruption.
> Important note: A virtual machine that has been marked
> highly-available can not be safely started on a different host
> without the certainty that doing so will not cause data corruption.
>
> N-joy,
>
> --Tareq
>
>
>
>
> On 01/27/2014 02:05 PM, Dafna Ron wrote:
>
> I am adding Tareq for the Power Management implementation.
>
> Dafna
>
>
> On 01/27/2014 11:48 AM, Karli Sjöberg wrote:
>
> On Mon, 2014-01-27 at 11:11 +0000, Dafna Ron wrote:
>
> Powering off the host will never trigger vm migration.
> As far as engine is concerned it just lost connection
> to the host, but
> has no way of telling if the host is down or if a
> router is down.
>
> Can´t it at least check with power management if the Host
> status is down
> first?
>
> I mean, if the network is down there will be no response
> from either PM
> or Host. But if PM is up and can tell you that the Host
> is down, sounds
> rather clear cut to me...
>
> Seems to me the VM's would be restarted sooner if the
> flow was altered
> to first check with PM if it´s a network or Host issue,
> and if Host
> issue, immediately restart VM's on another Host, instead
> of waiting for
> a potentially problematic Host to boot up eventually.
>
> /K
>
> since vm's can continue running on the host even if
> engine has no access
> to it, starting the vm's on the second host can cause
> split brain and
> data corruption.
>
> The way that the engine knows what's going on is by
> sending heath check
> queries to the vdsm.
> Power management will try to reboot a host when the
> health checks to
> vdsm will not be answered.
> So... if engine gets no reply and has no way of
> rebooting the host, the
> host status will be changed to Non-Responsive and the
> vm's will be
> unknown because engine has no way of knowing what's
> happening with the
> vm's.
> Since reboot of the host will kill the vm's running
> on it - this will
> never cause any vm migration but... along with the
> High-Availability vm
> feature, you will be able to have some of the vm's
> re-started on the
> second host after the host reboot (and that is only
> if Power Management
> was confirmed as successful).
>
> VM migration is only triggered when:
> 1. Cluster configuration states that the vm should be
> migrated in case
> of failure
> 2. Engine has access to the host - so the failure is
> on the storage side
> and not the host side.
> 3. the vms are not actively writing (although there
> might be a new RFE
> for it).
>
> hope this clears things up
>
> Dafna
>
>
>
> On 01/27/2014 10:11 AM, Andrew Lau wrote:
>
> Hi,
>
> Have you got power management enabled?
>
> That's the fencing feature required for the
> engine to ensure that the
> host is actually offline. It won't resume any
> other VMs to prevent
> potential VM corruption (eg. VM running on
> multiple hosts).
>
> Andrew.
>
> On Jan 27, 2014 5:12 PM, "Jaison peter"
> <urotrip2(a)gmail.com <mailto:urotrip2@gmail.com>
> <mailto:urotrip2@gmail.com
> <mailto:urotrip2@gmail.com>>> wrote:
>
> Hi all ,
>
> I was setting a two node ovirt cluster with
> ovirt engine on
> seperate node . I completed the
> configuration and tested VM live
> migrations with out any issues . Then for
> checking cluster HA I
> powered down one host and expected vms
> running on that host to be
> migrated to the other one . But nothing
> happened , Engine detected
> host as un-rechable and marked it as
> non-operational and vm ran on
> that host went to 'unknown state' . Is that
> not possible to setup
> a fully HA ovirt cluster with two nodes ? or
> else is that my
> configuration problem ? please advice .
>
> Thanks & Regards
>
> Alex
>
> _______________________________________________
> Users mailing list
> Users(a)ovirt.org <mailto:Users@ovirt.org>
> <mailto:Users@ovirt.org <mailto:Users@ovirt.org>>
> http://lists.ovirt.org/mailman/listinfo/users
>
>
>
> _______________________________________________
> Users mailing list
> Users(a)ovirt.org <mailto:Users@ovirt.org>
> http://lists.ovirt.org/mailman/listinfo/users
>
>
> --
> Dafna Ron
> _______________________________________________
> Users mailing list
> Users(a)ovirt.org <mailto:Users@ovirt.org>
> http://lists.ovirt.org/mailman/listinfo/users
>
>
>
>
>
>
>
--
Dafna Ron
4:40 p.m.
----- Original Message -----
From: "Tareq Alayan" <talayan(a)redhat.com>
To: "Andrew Lau" <andrew(a)andrewklau.com>, "Eli Mesika"
<emesika(a)redhat.com>
Cc: dron(a)redhat.com, "Karli Sjöberg" <Karli.Sjoberg(a)slu.se>,
users(a)ovirt.org
Sent: Monday, January 27, 2014 2:59:02 PM
Subject: Re: [Users] two node ovirt cluster with HA
Adding Eli.
I just want to summarize the requirement as I understand it:
In the case that a Host that is running HA VMs and have PM configured is turned off
manually :
1) The non-responsive treatment should be modified to check Host status via PM agent
2) If Host is off , HA VMs will attempt to run on another host ASAP
3) The host status should be set to DOWN
4) No attempt to restart vdsm (soft fencing) or restart the host (hard fencing) will be
done
Is the above correct? if so , a RFE on that can be opened
On 01/27/2014 02:50 PM, Andrew Lau wrote:
> Hi,
>
> I think he was asking what if the power management device reported
> that the host was powered off. Then VMs should be brought back up as
> being off would essentially be the same as running a power cycle/reboot?
>
> Another example I'm seeing is what happens if the whole host loses
> power and it's power management device then becomes unavailable (ie.
> not reachable) then you're stuck in the case where it requires manual
> intervention.
>
> I would be interested to potentially see something like a timeout on
> those problematic VMs (eg. if nothing was read or write after x amount
> of time) then you could consider the host as offline? I guess then
> that adds a lot of risk..
>
>
> On Mon, Jan 27, 2014 at 11:43 PM, Tareq Alayan <talayan(a)redhat.com
> <mailto:talayan@redhat.com>> wrote:
>
> Hi,
>
> Power management makes use of special *dedicated* hardware in
> order to restart hosts independently of host OS. The engine
> connects to a power management devices using a *dedicated* network
> IP address.
> The engine is capable of rebooting hosts that have entered a
> non-operational or non-responsive state,
> The abilities provided by all power management devices are: check
> status, start, stop and recycle (restart)...
>
> In the case of non-responsive host: all of the VMs that are
> currently running on that host can also become non-responsive.
> However, the non-responsive host keeps locking the VM hard disk
> for all VMs it is running. Attempting to start a VM on a different
> host and assign the second host write privileges for the virtual
> machine hard disk image can cause data corruption.
> Rebooting allows the engine to assume that the lock on a VM hard
> disk image has been released.
> The engine can know for sure that the problematic host has been
> rebooted via the power management device and then it can start a
> VM from the problematic host on another host without risking data
> corruption.
> Important note: A virtual machine that has been marked
> highly-available can not be safely started on a different host
> without the certainty that doing so will not cause data corruption.
>
> N-joy,
>
> --Tareq
>
>
>
>
> On 01/27/2014 02:05 PM, Dafna Ron wrote:
>
> I am adding Tareq for the Power Management implementation.
>
> Dafna
>
>
> On 01/27/2014 11:48 AM, Karli Sjöberg wrote:
>
> On Mon, 2014-01-27 at 11:11 +0000, Dafna Ron wrote:
>
> Powering off the host will never trigger vm migration.
> As far as engine is concerned it just lost connection
> to the host, but
> has no way of telling if the host is down or if a
> router is down.
>
> Can´t it at least check with power management if the Host
> status is down
> first?
>
> I mean, if the network is down there will be no response
> from either PM
> or Host. But if PM is up and can tell you that the Host is
> down, sounds
> rather clear cut to me...
>
> Seems to me the VM's would be restarted sooner if the flow
> was altered
> to first check with PM if it´s a network or Host issue,
> and if Host
> issue, immediately restart VM's on another Host, instead
> of waiting for
> a potentially problematic Host to boot up eventually.
>
> /K
>
> since vm's can continue running on the host even if
> engine has no access
> to it, starting the vm's on the second host can cause
> split brain and
> data corruption.
>
> The way that the engine knows what's going on is by
> sending heath check
> queries to the vdsm.
> Power management will try to reboot a host when the
> health checks to
> vdsm will not be answered.
> So... if engine gets no reply and has no way of
> rebooting the host, the
> host status will be changed to Non-Responsive and the
> vm's will be
> unknown because engine has no way of knowing what's
> happening with the
> vm's.
> Since reboot of the host will kill the vm's running on
> it - this will
> never cause any vm migration but... along with the
> High-Availability vm
> feature, you will be able to have some of the vm's
> re-started on the
> second host after the host reboot (and that is only if
> Power Management
> was confirmed as successful).
>
> VM migration is only triggered when:
> 1. Cluster configuration states that the vm should be
> migrated in case
> of failure
> 2. Engine has access to the host - so the failure is
> on the storage side
> and not the host side.
> 3. the vms are not actively writing (although there
> might be a new RFE
> for it).
>
> hope this clears things up
>
> Dafna
>
>
>
> On 01/27/2014 10:11 AM, Andrew Lau wrote:
>
> Hi,
>
> Have you got power management enabled?
>
> That's the fencing feature required for the engine
> to ensure that the
> host is actually offline. It won't resume any
> other VMs to prevent
> potential VM corruption (eg. VM running on
> multiple hosts).
>
> Andrew.
>
> On Jan 27, 2014 5:12 PM, "Jaison peter"
> <urotrip2(a)gmail.com <mailto:urotrip2@gmail.com>
> <mailto:urotrip2@gmail.com
> <mailto:urotrip2@gmail.com>>> wrote:
>
> Hi all ,
>
> I was setting a two node ovirt cluster with
> ovirt engine on
> seperate node . I completed the configuration
> and tested VM live
> migrations with out any issues . Then for
> checking cluster HA I
> powered down one host and expected vms
> running on that host to be
> migrated to the other one . But nothing
> happened , Engine detected
> host as un-rechable and marked it as
> non-operational and vm ran on
> that host went to 'unknown state' . Is that
> not possible to setup
> a fully HA ovirt cluster with two nodes ? or
> else is that my
> configuration problem ? please advice .
>
> Thanks & Regards
>
> Alex
>
> _______________________________________________
> Users mailing list
> Users(a)ovirt.org <mailto:Users@ovirt.org>
> <mailto:Users@ovirt.org <mailto:Users@ovirt.org>>
> http://lists.ovirt.org/mailman/listinfo/users
>
>
>
> _______________________________________________
> Users mailing list
> Users(a)ovirt.org <mailto:Users@ovirt.org>
> http://lists.ovirt.org/mailman/listinfo/users
>
>
> --
> Dafna Ron
> _______________________________________________
> Users mailing list
> Users(a)ovirt.org <mailto:Users@ovirt.org>
> http://lists.ovirt.org/mailman/listinfo/users
>
>
>
>
>
>
>
6:33 a.m.
Thank you all for your valuable feedback .
Can you please specify some of the supported fencing devices in ovirt ?
On Mon, Jan 27, 2014 at 9:10 PM, Eli Mesika <emesika(a)redhat.com> wrote:
----- Original Message -----
> From: "Tareq Alayan" <talayan(a)redhat.com>
> To: "Andrew Lau" <andrew(a)andrewklau.com>, "Eli Mesika"
<
emesika(a)redhat.com>
> Cc: dron(a)redhat.com, "Karli Sjöberg" <Karli.Sjoberg(a)slu.se>,
users(a)ovirt.org
> Sent: Monday, January 27, 2014 2:59:02 PM
> Subject: Re: [Users] two node ovirt cluster with HA
>
> Adding Eli.
I just want to summarize the requirement as I understand it:
In the case that a Host that is running HA VMs and have PM configured is
turned off manually :
1) The non-responsive treatment should be modified to check Host status
via PM agent
2) If Host is off , HA VMs will attempt to run on another host ASAP
3) The host status should be set to DOWN
4) No attempt to restart vdsm (soft fencing) or restart the host (hard
fencing) will be done
Is the above correct? if so , a RFE on that can be opened
>
>
> On 01/27/2014 02:50 PM, Andrew Lau wrote:
> > Hi,
> >
> > I think he was asking what if the power management device reported
> > that the host was powered off. Then VMs should be brought back up as
> > being off would essentially be the same as running a power
cycle/reboot?
> >
> > Another example I'm seeing is what happens if the whole host loses
> > power and it's power management device then becomes unavailable (ie.
> > not reachable) then you're stuck in the case where it requires manual
> > intervention.
> >
> > I would be interested to potentially see something like a timeout on
> > those problematic VMs (eg. if nothing was read or write after x amount
> > of time) then you could consider the host as offline? I guess then
> > that adds a lot of risk..
> >
> >
> > On Mon, Jan 27, 2014 at 11:43 PM, Tareq Alayan <talayan(a)redhat.com
> > <mailto:talayan@redhat.com>> wrote:
> >
> > Hi,
> >
> > Power management makes use of special *dedicated* hardware in
> > order to restart hosts independently of host OS. The engine
> > connects to a power management devices using a *dedicated* network
> > IP address.
> > The engine is capable of rebooting hosts that have entered a
> > non-operational or non-responsive state,
> > The abilities provided by all power management devices are: check
> > status, start, stop and recycle (restart)...
> >
> > In the case of non-responsive host: all of the VMs that are
> > currently running on that host can also become non-responsive.
> > However, the non-responsive host keeps locking the VM hard disk
> > for all VMs it is running. Attempting to start a VM on a different
> > host and assign the second host write privileges for the virtual
> > machine hard disk image can cause data corruption.
> > Rebooting allows the engine to assume that the lock on a VM hard
> > disk image has been released.
> > The engine can know for sure that the problematic host has been
> > rebooted via the power management device and then it can start a
> > VM from the problematic host on another host without risking data
> > corruption.
> > Important note: A virtual machine that has been marked
> > highly-available can not be safely started on a different host
> > without the certainty that doing so will not cause data corruption.
> >
> > N-joy,
> >
> > --Tareq
> >
> >
> >
> >
> > On 01/27/2014 02:05 PM, Dafna Ron wrote:
> >
> > I am adding Tareq for the Power Management implementation.
> >
> > Dafna
> >
> >
> > On 01/27/2014 11:48 AM, Karli Sjöberg wrote:
> >
> > On Mon, 2014-01-27 at 11:11 +0000, Dafna Ron wrote:
> >
> > Powering off the host will never trigger vm migration.
> > As far as engine is concerned it just lost connection
> > to the host, but
> > has no way of telling if the host is down or if a
> > router is down.
> >
> > Can´t it at least check with power management if the Host
> > status is down
> > first?
> >
> > I mean, if the network is down there will be no response
> > from either PM
> > or Host. But if PM is up and can tell you that the Host is
> > down, sounds
> > rather clear cut to me...
> >
> > Seems to me the VM's would be restarted sooner if the flow
> > was altered
> > to first check with PM if it´s a network or Host issue,
> > and if Host
> > issue, immediately restart VM's on another Host, instead
> > of waiting for
> > a potentially problematic Host to boot up eventually.
> >
> > /K
> >
> > since vm's can continue running on the host even if
> > engine has no access
> > to it, starting the vm's on the second host can cause
> > split brain and
> > data corruption.
> >
> > The way that the engine knows what's going on is by
> > sending heath check
> > queries to the vdsm.
> > Power management will try to reboot a host when the
> > health checks to
> > vdsm will not be answered.
> > So... if engine gets no reply and has no way of
> > rebooting the host, the
> > host status will be changed to Non-Responsive and the
> > vm's will be
> > unknown because engine has no way of knowing what's
> > happening with the
> > vm's.
> > Since reboot of the host will kill the vm's running on
> > it - this will
> > never cause any vm migration but... along with the
> > High-Availability vm
> > feature, you will be able to have some of the vm's
> > re-started on the
> > second host after the host reboot (and that is only if
> > Power Management
> > was confirmed as successful).
> >
> > VM migration is only triggered when:
> > 1. Cluster configuration states that the vm should be
> > migrated in case
> > of failure
> > 2. Engine has access to the host - so the failure is
> > on the storage side
> > and not the host side.
> > 3. the vms are not actively writing (although there
> > might be a new RFE
> > for it).
> >
> > hope this clears things up
> >
> > Dafna
> >
> >
> >
> > On 01/27/2014 10:11 AM, Andrew Lau wrote:
> >
> > Hi,
> >
> > Have you got power management enabled?
> >
> > That's the fencing feature required for the engine
> > to ensure that the
> > host is actually offline. It won't resume any
> > other VMs to prevent
> > potential VM corruption (eg. VM running on
> > multiple hosts).
> >
> > Andrew.
> >
> > On Jan 27, 2014 5:12 PM, "Jaison peter"
> > <urotrip2(a)gmail.com <mailto:urotrip2@gmail.com>
> > <mailto:urotrip2@gmail.com
> > <mailto:urotrip2@gmail.com>>> wrote:
> >
> > Hi all ,
> >
> > I was setting a two node ovirt cluster with
> > ovirt engine on
> > seperate node . I completed the configuration
> > and tested VM live
> > migrations with out any issues . Then for
> > checking cluster HA I
> > powered down one host and expected vms
> > running on that host to be
> > migrated to the other one . But nothing
> > happened , Engine detected
> > host as un-rechable and marked it as
> > non-operational and vm ran on
> > that host went to 'unknown state' . Is that
> > not possible to setup
> > a fully HA ovirt cluster with two nodes ? or
> > else is that my
> > configuration problem ? please advice .
> >
> > Thanks & Regards
> >
> > Alex
> >
> >
_______________________________________________
> > Users mailing list
> > Users(a)ovirt.org <mailto:Users@ovirt.org>
> > <mailto:Users@ovirt.org
<mailto:Users@ovirt.org>>
> > http://lists.ovirt.org/mailman/listinfo/users
> >
> >
> >
> > _______________________________________________
> > Users mailing list
> > Users(a)ovirt.org <mailto:Users@ovirt.org>
> > http://lists.ovirt.org/mailman/listinfo/users
> >
> >
> > --
> > Dafna Ron
> > _______________________________________________
> > Users mailing list
> > Users(a)ovirt.org <mailto:Users@ovirt.org>
> > http://lists.ovirt.org/mailman/listinfo/users
> >
> >
> >
> >
> >
> >
> >
>
>
_______________________________________________
Users mailing list
Users(a)ovirt.org
http://lists.ovirt.org/mailman/listinfo/users
9:30 a.m.
Skickat från min iPhone
27 jan 2014 kl. 16:40 skrev "Eli Mesika"
<emesika(a)redhat.com>:
----- Original Message -----
> From: "Tareq Alayan" <talayan(a)redhat.com>
> To: "Andrew Lau" <andrew(a)andrewklau.com>, "Eli Mesika"
<emesika(a)redhat.com>
> Cc: dron(a)redhat.com, "Karli Sjöberg" <Karli.Sjoberg(a)slu.se>,
users(a)ovirt.org
> Sent: Monday, January 27, 2014 2:59:02 PM
> Subject: Re: [Users] two node ovirt cluster with HA
>
> Adding Eli.
I just want to summarize the requirement as I understand it:
In the case that a Host that is running HA VMs and have PM configured is turned off
manually :
1) The non-responsive treatment should be modified to check Host status via PM agent
2) If Host is off , HA VMs will attempt to run on another host ASAP
3) The host status should be set to DOWN
4) No attempt to restart vdsm (soft fencing) or restart the host (hard fencing) will be
done
Is the above correct? if so , a RFE on that can be opened
Spot on, that's exactly what I was trying to say! I'd very much like to see an RFE
for that.
/K
>
>
>> On 01/27/2014 02:50 PM, Andrew Lau wrote:
>> Hi,
>>
>> I think he was asking what if the power management device reported
>> that the host was powered off. Then VMs should be brought back up as
>> being off would essentially be the same as running a power cycle/reboot?
>>
>> Another example I'm seeing is what happens if the whole host loses
>> power and it's power management device then becomes unavailable (ie.
>> not reachable) then you're stuck in the case where it requires manual
>> intervention.
>>
>> I would be interested to potentially see something like a timeout on
>> those problematic VMs (eg. if nothing was read or write after x amount
>> of time) then you could consider the host as offline? I guess then
>> that adds a lot of risk..
>>
>>
>> On Mon, Jan 27, 2014 at 11:43 PM, Tareq Alayan <talayan(a)redhat.com
>> <mailto:talayan@redhat.com>> wrote:
>>
>> Hi,
>>
>> Power management makes use of special *dedicated* hardware in
>> order to restart hosts independently of host OS. The engine
>> connects to a power management devices using a *dedicated* network
>> IP address.
>> The engine is capable of rebooting hosts that have entered a
>> non-operational or non-responsive state,
>> The abilities provided by all power management devices are: check
>> status, start, stop and recycle (restart)...
>>
>> In the case of non-responsive host: all of the VMs that are
>> currently running on that host can also become non-responsive.
>> However, the non-responsive host keeps locking the VM hard disk
>> for all VMs it is running. Attempting to start a VM on a different
>> host and assign the second host write privileges for the virtual
>> machine hard disk image can cause data corruption.
>> Rebooting allows the engine to assume that the lock on a VM hard
>> disk image has been released.
>> The engine can know for sure that the problematic host has been
>> rebooted via the power management device and then it can start a
>> VM from the problematic host on another host without risking data
>> corruption.
>> Important note: A virtual machine that has been marked
>> highly-available can not be safely started on a different host
>> without the certainty that doing so will not cause data corruption.
>>
>> N-joy,
>>
>> --Tareq
>>
>>
>>
>>
>> On 01/27/2014 02:05 PM, Dafna Ron wrote:
>>
>> I am adding Tareq for the Power Management implementation.
>>
>> Dafna
>>
>>
>> On 01/27/2014 11:48 AM, Karli Sjöberg wrote:
>>
>> On Mon, 2014-01-27 at 11:11 +0000, Dafna Ron wrote:
>>
>> Powering off the host will never trigger vm migration.
>> As far as engine is concerned it just lost connection
>> to the host, but
>> has no way of telling if the host is down or if a
>> router is down.
>>
>> Can´t it at least check with power management if the Host
>> status is down
>> first?
>>
>> I mean, if the network is down there will be no response
>> from either PM
>> or Host. But if PM is up and can tell you that the Host is
>> down, sounds
>> rather clear cut to me...
>>
>> Seems to me the VM's would be restarted sooner if the flow
>> was altered
>> to first check with PM if it´s a network or Host issue,
>> and if Host
>> issue, immediately restart VM's on another Host, instead
>> of waiting for
>> a potentially problematic Host to boot up eventually.
>>
>> /K
>>
>> since vm's can continue running on the host even if
>> engine has no access
>> to it, starting the vm's on the second host can cause
>> split brain and
>> data corruption.
>>
>> The way that the engine knows what's going on is by
>> sending heath check
>> queries to the vdsm.
>> Power management will try to reboot a host when the
>> health checks to
>> vdsm will not be answered.
>> So... if engine gets no reply and has no way of
>> rebooting the host, the
>> host status will be changed to Non-Responsive and the
>> vm's will be
>> unknown because engine has no way of knowing what's
>> happening with the
>> vm's.
>> Since reboot of the host will kill the vm's running on
>> it - this will
>> never cause any vm migration but... along with the
>> High-Availability vm
>> feature, you will be able to have some of the vm's
>> re-started on the
>> second host after the host reboot (and that is only if
>> Power Management
>> was confirmed as successful).
>>
>> VM migration is only triggered when:
>> 1. Cluster configuration states that the vm should be
>> migrated in case
>> of failure
>> 2. Engine has access to the host - so the failure is
>> on the storage side
>> and not the host side.
>> 3. the vms are not actively writing (although there
>> might be a new RFE
>> for it).
>>
>> hope this clears things up
>>
>> Dafna
>>
>>
>>
>> On 01/27/2014 10:11 AM, Andrew Lau wrote:
>>
>> Hi,
>>
>> Have you got power management enabled?
>>
>> That's the fencing feature required for the engine
>> to ensure that the
>> host is actually offline. It won't resume any
>> other VMs to prevent
>> potential VM corruption (eg. VM running on
>> multiple hosts).
>>
>> Andrew.
>>
>> On Jan 27, 2014 5:12 PM, "Jaison peter"
>> <urotrip2(a)gmail.com <mailto:urotrip2@gmail.com>
>> <mailto:urotrip2@gmail.com
>> <mailto:urotrip2@gmail.com>>> wrote:
>>
>> Hi all ,
>>
>> I was setting a two node ovirt cluster with
>> ovirt engine on
>> seperate node . I completed the configuration
>> and tested VM live
>> migrations with out any issues . Then for
>> checking cluster HA I
>> powered down one host and expected vms
>> running on that host to be
>> migrated to the other one . But nothing
>> happened , Engine detected
>> host as un-rechable and marked it as
>> non-operational and vm ran on
>> that host went to 'unknown state' . Is that
>> not possible to setup
>> a fully HA ovirt cluster with two nodes ? or
>> else is that my
>> configuration problem ? please advice .
>>
>> Thanks & Regards
>>
>> Alex
>>
>> _______________________________________________
>> Users mailing list
>> Users(a)ovirt.org <mailto:Users@ovirt.org>
>> <mailto:Users@ovirt.org <mailto:Users@ovirt.org>>
>> http://lists.ovirt.org/mailman/listinfo/users
>>
>>
>>
>> _______________________________________________
>> Users mailing list
>> Users(a)ovirt.org <mailto:Users@ovirt.org>
>> http://lists.ovirt.org/mailman/listinfo/users
>>
>>
>> --
>> Dafna Ron
>> _______________________________________________
>> Users mailing list
>> Users(a)ovirt.org <mailto:Users@ovirt.org>
>> http://lists.ovirt.org/mailman/listinfo/users
>
>
9:34 a.m.
----- Original Message -----
From: "Jaison peter" <urotrip2(a)gmail.com>
To: "Eli Mesika" <emesika(a)redhat.com>
Cc: users(a)ovirt.org, "Tareq Alayan" <talayan(a)redhat.com>
Sent: Tuesday, January 28, 2014 7:33:35 AM
Subject: Re: [Users] two node ovirt cluster with HA
Thank you all for your valuable feedback .
Can you please specify some of the supported fencing devices in ovirt ?
For oVirt 3.4 :
apc,apc_snmp,bladecenter,cisco_ucs,drac5,drac7,eps,hpblade,ilo,ilo2,ilo3,ilo4,ipmilan,rsa,rsb,wti
On Mon, Jan 27, 2014 at 9:10 PM, Eli Mesika <emesika(a)redhat.com> wrote:
>
>
> ----- Original Message -----
> > From: "Tareq Alayan" <talayan(a)redhat.com>
> > To: "Andrew Lau" <andrew(a)andrewklau.com>, "Eli
Mesika" <
> emesika(a)redhat.com>
> > Cc: dron(a)redhat.com, "Karli Sjöberg" <Karli.Sjoberg(a)slu.se>,
> users(a)ovirt.org
> > Sent: Monday, January 27, 2014 2:59:02 PM
> > Subject: Re: [Users] two node ovirt cluster with HA
> >
> > Adding Eli.
>
> I just want to summarize the requirement as I understand it:
>
> In the case that a Host that is running HA VMs and have PM configured is
> turned off manually :
>
> 1) The non-responsive treatment should be modified to check Host status
> via PM agent
> 2) If Host is off , HA VMs will attempt to run on another host ASAP
> 3) The host status should be set to DOWN
> 4) No attempt to restart vdsm (soft fencing) or restart the host (hard
> fencing) will be done
>
> Is the above correct? if so , a RFE on that can be opened
>
> >
> >
> > On 01/27/2014 02:50 PM, Andrew Lau wrote:
> > > Hi,
> > >
> > > I think he was asking what if the power management device reported
> > > that the host was powered off. Then VMs should be brought back up as
> > > being off would essentially be the same as running a power
> cycle/reboot?
> > >
> > > Another example I'm seeing is what happens if the whole host loses
> > > power and it's power management device then becomes unavailable (ie.
> > > not reachable) then you're stuck in the case where it requires manual
> > > intervention.
> > >
> > > I would be interested to potentially see something like a timeout on
> > > those problematic VMs (eg. if nothing was read or write after x amount
> > > of time) then you could consider the host as offline? I guess then
> > > that adds a lot of risk..
> > >
> > >
> > > On Mon, Jan 27, 2014 at 11:43 PM, Tareq Alayan <talayan(a)redhat.com
> > > <mailto:talayan@redhat.com>> wrote:
> > >
> > > Hi,
> > >
> > > Power management makes use of special *dedicated* hardware in
> > > order to restart hosts independently of host OS. The engine
> > > connects to a power management devices using a *dedicated* network
> > > IP address.
> > > The engine is capable of rebooting hosts that have entered a
> > > non-operational or non-responsive state,
> > > The abilities provided by all power management devices are: check
> > > status, start, stop and recycle (restart)...
> > >
> > > In the case of non-responsive host: all of the VMs that are
> > > currently running on that host can also become non-responsive.
> > > However, the non-responsive host keeps locking the VM hard disk
> > > for all VMs it is running. Attempting to start a VM on a different
> > > host and assign the second host write privileges for the virtual
> > > machine hard disk image can cause data corruption.
> > > Rebooting allows the engine to assume that the lock on a VM hard
> > > disk image has been released.
> > > The engine can know for sure that the problematic host has been
> > > rebooted via the power management device and then it can start a
> > > VM from the problematic host on another host without risking data
> > > corruption.
> > > Important note: A virtual machine that has been marked
> > > highly-available can not be safely started on a different host
> > > without the certainty that doing so will not cause data corruption.
> > >
> > > N-joy,
> > >
> > > --Tareq
> > >
> > >
> > >
> > >
> > > On 01/27/2014 02:05 PM, Dafna Ron wrote:
> > >
> > > I am adding Tareq for the Power Management implementation.
> > >
> > > Dafna
> > >
> > >
> > > On 01/27/2014 11:48 AM, Karli Sjöberg wrote:
> > >
> > > On Mon, 2014-01-27 at 11:11 +0000, Dafna Ron wrote:
> > >
> > > Powering off the host will never trigger vm migration.
> > > As far as engine is concerned it just lost connection
> > > to the host, but
> > > has no way of telling if the host is down or if a
> > > router is down.
> > >
> > > Can´t it at least check with power management if the Host
> > > status is down
> > > first?
> > >
> > > I mean, if the network is down there will be no response
> > > from either PM
> > > or Host. But if PM is up and can tell you that the Host is
> > > down, sounds
> > > rather clear cut to me...
> > >
> > > Seems to me the VM's would be restarted sooner if the
flow
> > > was altered
> > > to first check with PM if it´s a network or Host issue,
> > > and if Host
> > > issue, immediately restart VM's on another Host, instead
> > > of waiting for
> > > a potentially problematic Host to boot up eventually.
> > >
> > > /K
> > >
> > > since vm's can continue running on the host even if
> > > engine has no access
> > > to it, starting the vm's on the second host can cause
> > > split brain and
> > > data corruption.
> > >
> > > The way that the engine knows what's going on is by
> > > sending heath check
> > > queries to the vdsm.
> > > Power management will try to reboot a host when the
> > > health checks to
> > > vdsm will not be answered.
> > > So... if engine gets no reply and has no way of
> > > rebooting the host, the
> > > host status will be changed to Non-Responsive and the
> > > vm's will be
> > > unknown because engine has no way of knowing what's
> > > happening with the
> > > vm's.
> > > Since reboot of the host will kill the vm's running
on
> > > it - this will
> > > never cause any vm migration but... along with the
> > > High-Availability vm
> > > feature, you will be able to have some of the vm's
> > > re-started on the
> > > second host after the host reboot (and that is only if
> > > Power Management
> > > was confirmed as successful).
> > >
> > > VM migration is only triggered when:
> > > 1. Cluster configuration states that the vm should be
> > > migrated in case
> > > of failure
> > > 2. Engine has access to the host - so the failure is
> > > on the storage side
> > > and not the host side.
> > > 3. the vms are not actively writing (although there
> > > might be a new RFE
> > > for it).
> > >
> > > hope this clears things up
> > >
> > > Dafna
> > >
> > >
> > >
> > > On 01/27/2014 10:11 AM, Andrew Lau wrote:
> > >
> > > Hi,
> > >
> > > Have you got power management enabled?
> > >
> > > That's the fencing feature required for the
engine
> > > to ensure that the
> > > host is actually offline. It won't resume any
> > > other VMs to prevent
> > > potential VM corruption (eg. VM running on
> > > multiple hosts).
> > >
> > > Andrew.
> > >
> > > On Jan 27, 2014 5:12 PM, "Jaison peter"
> > > <urotrip2(a)gmail.com
<mailto:urotrip2@gmail.com>
> > > <mailto:urotrip2@gmail.com
> > > <mailto:urotrip2@gmail.com>>> wrote:
> > >
> > > Hi all ,
> > >
> > > I was setting a two node ovirt cluster with
> > > ovirt engine on
> > > seperate node . I completed the configuration
> > > and tested VM live
> > > migrations with out any issues . Then for
> > > checking cluster HA I
> > > powered down one host and expected vms
> > > running on that host to be
> > > migrated to the other one . But nothing
> > > happened , Engine detected
> > > host as un-rechable and marked it as
> > > non-operational and vm ran on
> > > that host went to 'unknown state' . Is
that
> > > not possible to setup
> > > a fully HA ovirt cluster with two nodes ? or
> > > else is that my
> > > configuration problem ? please advice .
> > >
> > > Thanks & Regards
> > >
> > > Alex
> > >
> > >
> _______________________________________________
> > > Users mailing list
> > > Users(a)ovirt.org <mailto:Users@ovirt.org>
> > > <mailto:Users@ovirt.org
<mailto:Users@ovirt.org>>
> > > http://lists.ovirt.org/mailman/listinfo/users
> > >
> > >
> > >
> > > _______________________________________________
> > > Users mailing list
> > > Users(a)ovirt.org <mailto:Users@ovirt.org>
> > > http://lists.ovirt.org/mailman/listinfo/users
> > >
> > >
> > > --
> > > Dafna Ron
> > > _______________________________________________
> > > Users mailing list
> > > Users(a)ovirt.org <mailto:Users@ovirt.org>
> > > http://lists.ovirt.org/mailman/listinfo/users
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> >
> >
> _______________________________________________
> Users mailing list
> Users(a)ovirt.org
> http://lists.ovirt.org/mailman/listinfo/users
>
9:40 a.m.
Thanks !
On Tue, Jan 28, 2014 at 2:04 PM, Eli Mesika <emesika(a)redhat.com> wrote:
----- Original Message -----
> From: "Jaison peter" <urotrip2(a)gmail.com>
> To: "Eli Mesika" <emesika(a)redhat.com>
> Cc: users(a)ovirt.org, "Tareq Alayan" <talayan(a)redhat.com>
> Sent: Tuesday, January 28, 2014 7:33:35 AM
> Subject: Re: [Users] two node ovirt cluster with HA
>
> Thank you all for your valuable feedback .
>
> Can you please specify some of the supported fencing devices in ovirt ?
For oVirt 3.4 :
apc,apc_snmp,bladecenter,cisco_ucs,drac5,drac7,eps,hpblade,ilo,ilo2,ilo3,ilo4,ipmilan,rsa,rsb,wti
>
>
> On Mon, Jan 27, 2014 at 9:10 PM, Eli Mesika <emesika(a)redhat.com> wrote:
>
> >
> >
> > ----- Original Message -----
> > > From: "Tareq Alayan" <talayan(a)redhat.com>
> > > To: "Andrew Lau" <andrew(a)andrewklau.com>, "Eli
Mesika" <
> > emesika(a)redhat.com>
> > > Cc: dron(a)redhat.com, "Karli Sjöberg"
<Karli.Sjoberg(a)slu.se>,
> > users(a)ovirt.org
> > > Sent: Monday, January 27, 2014 2:59:02 PM
> > > Subject: Re: [Users] two node ovirt cluster with HA
> > >
> > > Adding Eli.
> >
> > I just want to summarize the requirement as I understand it:
> >
> > In the case that a Host that is running HA VMs and have PM configured
is
> > turned off manually :
> >
> > 1) The non-responsive treatment should be modified to check Host status
> > via PM agent
> > 2) If Host is off , HA VMs will attempt to run on another host ASAP
> > 3) The host status should be set to DOWN
> > 4) No attempt to restart vdsm (soft fencing) or restart the host (hard
> > fencing) will be done
> >
> > Is the above correct? if so , a RFE on that can be opened
> >
> > >
> > >
> > > On 01/27/2014 02:50 PM, Andrew Lau wrote:
> > > > Hi,
> > > >
> > > > I think he was asking what if the power management device reported
> > > > that the host was powered off. Then VMs should be brought back up
as
> > > > being off would essentially be the same as running a power
> > cycle/reboot?
> > > >
> > > > Another example I'm seeing is what happens if the whole host
loses
> > > > power and it's power management device then becomes unavailable
(ie.
> > > > not reachable) then you're stuck in the case where it requires
manual
> > > > intervention.
> > > >
> > > > I would be interested to potentially see something like a timeout
on
> > > > those problematic VMs (eg. if nothing was read or write after x
amount
> > > > of time) then you could consider the host as offline? I guess then
> > > > that adds a lot of risk..
> > > >
> > > >
> > > > On Mon, Jan 27, 2014 at 11:43 PM, Tareq Alayan
<talayan(a)redhat.com
> > > > <mailto:talayan@redhat.com>> wrote:
> > > >
> > > > Hi,
> > > >
> > > > Power management makes use of special *dedicated* hardware in
> > > > order to restart hosts independently of host OS. The engine
> > > > connects to a power management devices using a *dedicated*
network
> > > > IP address.
> > > > The engine is capable of rebooting hosts that have entered a
> > > > non-operational or non-responsive state,
> > > > The abilities provided by all power management devices are:
check
> > > > status, start, stop and recycle (restart)...
> > > >
> > > > In the case of non-responsive host: all of the VMs that are
> > > > currently running on that host can also become non-responsive.
> > > > However, the non-responsive host keeps locking the VM hard disk
> > > > for all VMs it is running. Attempting to start a VM on a
different
> > > > host and assign the second host write privileges for the
virtual
> > > > machine hard disk image can cause data corruption.
> > > > Rebooting allows the engine to assume that the lock on a VM
hard
> > > > disk image has been released.
> > > > The engine can know for sure that the problematic host has been
> > > > rebooted via the power management device and then it can start
a
> > > > VM from the problematic host on another host without risking
data
> > > > corruption.
> > > > Important note: A virtual machine that has been marked
> > > > highly-available can not be safely started on a different host
> > > > without the certainty that doing so will not cause data
corruption.
> > > >
> > > > N-joy,
> > > >
> > > > --Tareq
> > > >
> > > >
> > > >
> > > >
> > > > On 01/27/2014 02:05 PM, Dafna Ron wrote:
> > > >
> > > > I am adding Tareq for the Power Management implementation.
> > > >
> > > > Dafna
> > > >
> > > >
> > > > On 01/27/2014 11:48 AM, Karli Sjöberg wrote:
> > > >
> > > > On Mon, 2014-01-27 at 11:11 +0000, Dafna Ron wrote:
> > > >
> > > > Powering off the host will never trigger vm
migration.
> > > > As far as engine is concerned it just lost
connection
> > > > to the host, but
> > > > has no way of telling if the host is down or if a
> > > > router is down.
> > > >
> > > > Can´t it at least check with power management if the
Host
> > > > status is down
> > > > first?
> > > >
> > > > I mean, if the network is down there will be no
response
> > > > from either PM
> > > > or Host. But if PM is up and can tell you that the
Host is
> > > > down, sounds
> > > > rather clear cut to me...
> > > >
> > > > Seems to me the VM's would be restarted sooner if
the
flow
> > > > was altered
> > > > to first check with PM if it´s a network or Host issue,
> > > > and if Host
> > > > issue, immediately restart VM's on another Host,
instead
> > > > of waiting for
> > > > a potentially problematic Host to boot up eventually.
> > > >
> > > > /K
> > > >
> > > > since vm's can continue running on the host even
if
> > > > engine has no access
> > > > to it, starting the vm's on the second host can
cause
> > > > split brain and
> > > > data corruption.
> > > >
> > > > The way that the engine knows what's going on is
by
> > > > sending heath check
> > > > queries to the vdsm.
> > > > Power management will try to reboot a host when the
> > > > health checks to
> > > > vdsm will not be answered.
> > > > So... if engine gets no reply and has no way of
> > > > rebooting the host, the
> > > > host status will be changed to Non-Responsive and
the
> > > > vm's will be
> > > > unknown because engine has no way of knowing
what's
> > > > happening with the
> > > > vm's.
> > > > Since reboot of the host will kill the vm's
running on
> > > > it - this will
> > > > never cause any vm migration but... along with the
> > > > High-Availability vm
> > > > feature, you will be able to have some of the
vm's
> > > > re-started on the
> > > > second host after the host reboot (and that is
only if
> > > > Power Management
> > > > was confirmed as successful).
> > > >
> > > > VM migration is only triggered when:
> > > > 1. Cluster configuration states that the vm should
be
> > > > migrated in case
> > > > of failure
> > > > 2. Engine has access to the host - so the failure
is
> > > > on the storage side
> > > > and not the host side.
> > > > 3. the vms are not actively writing (although there
> > > > might be a new RFE
> > > > for it).
> > > >
> > > > hope this clears things up
> > > >
> > > > Dafna
> > > >
> > > >
> > > >
> > > > On 01/27/2014 10:11 AM, Andrew Lau wrote:
> > > >
> > > > Hi,
> > > >
> > > > Have you got power management enabled?
> > > >
> > > > That's the fencing feature required for the
engine
> > > > to ensure that the
> > > > host is actually offline. It won't resume
any
> > > > other VMs to prevent
> > > > potential VM corruption (eg. VM running on
> > > > multiple hosts).
> > > >
> > > > Andrew.
> > > >
> > > > On Jan 27, 2014 5:12 PM, "Jaison
peter"
> > > > <urotrip2(a)gmail.com
<mailto:urotrip2@gmail.com
>
> > > > <mailto:urotrip2@gmail.com
> > > > <mailto:urotrip2@gmail.com>>> wrote:
> > > >
> > > > Hi all ,
> > > >
> > > > I was setting a two node ovirt cluster
with
> > > > ovirt engine on
> > > > seperate node . I completed the
configuration
> > > > and tested VM live
> > > > migrations with out any issues . Then for
> > > > checking cluster HA I
> > > > powered down one host and expected vms
> > > > running on that host to be
> > > > migrated to the other one . But nothing
> > > > happened , Engine detected
> > > > host as un-rechable and marked it as
> > > > non-operational and vm ran on
> > > > that host went to 'unknown state' .
Is
that
> > > > not possible to setup
> > > > a fully HA ovirt cluster with two nodes ?
or
> > > > else is that my
> > > > configuration problem ? please advice .
> > > >
> > > > Thanks & Regards
> > > >
> > > > Alex
> > > >
> > > >
> > _______________________________________________
> > > > Users mailing list
> > > > Users(a)ovirt.org <mailto:Users@ovirt.org>
> > > > <mailto:Users@ovirt.org <mailto:
Users(a)ovirt.org>>
> > > > http://lists.ovirt.org/mailman/listinfo/users
> > > >
> > > >
> > > >
> > > > _______________________________________________
> > > > Users mailing list
> > > > Users(a)ovirt.org <mailto:Users@ovirt.org>
> > > > http://lists.ovirt.org/mailman/listinfo/users
> > > >
> > > >
> > > > --
> > > > Dafna Ron
> > > > _______________________________________________
> > > > Users mailing list
> > > > Users(a)ovirt.org <mailto:Users@ovirt.org>
> > > > http://lists.ovirt.org/mailman/listinfo/users
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > >
> > >
> > _______________________________________________
> > Users mailing list
> > Users(a)ovirt.org
> > http://lists.ovirt.org/mailman/listinfo/users
> >
>
2:12 p.m.
On Tue, Jan 28, 2014 at 12:02 AM, Dafna Ron <dron(a)redhat.com> wrote:
Andrew,
Once this discussion is finished, and If what you like done is not in the
current implementation can you please open a bug/feature request for it?
Sure - I've opened a RFE here based on the current discussions
https://bugzilla.redhat.com/show_bug.cgi?id=1058737 but I'm not sure which
category it should be under.
Cheers,
Andrew.
6:09 p.m.
On 01/28/2014 01:12 PM, Andrew Lau wrote:
On Tue, Jan 28, 2014 at 12:02 AM, Dafna Ron <dron(a)redhat.com
<mailto:dron@redhat.com>>wrote:
Andrew,
Once this discussion is finished, and If what you like done is not
in the current implementation can you please open a bug/feature
request for it?
Sure - I've opened a RFE here based on the current discussions
https://bugzilla.redhat.com/show_bug.cgi?id=1058737 but I'm not sure
which category it should be under.
Cheers,
Andrew.
Thanks Andrew! I really appreciate it :)
--
Dafna Ron
9:04 a.m.
----- Original Message -----
From: "Andrew Lau" <andrew(a)andrewklau.com>
To: dron(a)redhat.com
Cc: "Tareq Alayan" <talayan(a)redhat.com>, "Eli Mesika"
<emesika(a)redhat.com>, "Karli Sjöberg" <Karli.Sjoberg(a)slu.se>,
users(a)ovirt.org
Sent: Tuesday, January 28, 2014 3:12:46 PM
Subject: Re: [Users] two node ovirt cluster with HA
On Tue, Jan 28, 2014 at 12:02 AM, Dafna Ron <dron(a)redhat.com> wrote:
> Andrew,
> Once this discussion is finished, and If what you like done is not in the
> current implementation can you please open a bug/feature request for it?
>
>
Sure - I've opened a RFE here based on the current discussions
https://bugzilla.redhat.com/show_bug.cgi?id=1058737 but I'm not sure which
category it should be under.
I had assigned it to infra , thanks
IMHO we should handle only the first scenario reported in this BZ
Cheers,
Andrew.
12:01 p.m.
----- Original Message -----
From: "Tareq Alayan" <talayan(a)redhat.com>
To: dron(a)redhat.com, "Karli Sjöberg" <Karli.Sjoberg(a)slu.se>
Cc: users(a)ovirt.org
Sent: Monday, January 27, 2014 2:43:29 PM
Subject: Re: [Users] two node ovirt cluster with HA
Hi,
Power management makes use of special *dedicated* hardware in order to
restart hosts independently of host OS. The engine connects to a power
management devices using a *dedicated* network IP address.
The engine is capable of rebooting hosts that have entered a
non-operational or non-responsive state,
non-operational is related to storage issues so the Host will not be restarted by PM in
this case
The abilities provided by all power management devices are: check
status, start, stop and recycle (restart)...
Only status, start, stop while restart is implemented as stop->wait to off
status->start->wait to on status
In the case of non-responsive host: all of the VMs that are currently
running on that host can also become non-responsive. However, the
non-responsive host keeps locking the VM hard disk for all VMs it is
running. Attempting to start a VM on a different host and assign the
second host write privileges for the virtual machine hard disk image can
cause data corruption.
Rebooting allows the engine to assume that the lock on a VM hard disk
image has been released.
The engine can know for sure that the problematic host has been rebooted
via the power management device and then it can start a VM from the
problematic host on another host without risking data corruption.
Important note: A virtual machine that has been marked highly-available
can not be safely started on a different host without the certainty that
doing so will not cause data corruption.
N-joy,
--Tareq
On 01/27/2014 02:05 PM, Dafna Ron wrote:
> I am adding Tareq for the Power Management implementation.
>
> Dafna
>
>
> On 01/27/2014 11:48 AM, Karli Sjöberg wrote:
>> On Mon, 2014-01-27 at 11:11 +0000, Dafna Ron wrote:
>>> Powering off the host will never trigger vm migration.
>>> As far as engine is concerned it just lost connection to the host, but
>>> has no way of telling if the host is down or if a router is down.
>> Can´t it at least check with power management if the Host status is down
>> first?
>>
>> I mean, if the network is down there will be no response from either PM
>> or Host. But if PM is up and can tell you that the Host is down, sounds
>> rather clear cut to me...
>>
>> Seems to me the VM's would be restarted sooner if the flow was altered
>> to first check with PM if it´s a network or Host issue, and if Host
>> issue, immediately restart VM's on another Host, instead of waiting for
>> a potentially problematic Host to boot up eventually.
>>
>> /K
>>
>>> since vm's can continue running on the host even if engine has no
>>> access
>>> to it, starting the vm's on the second host can cause split brain and
>>> data corruption.
>>>
>>> The way that the engine knows what's going on is by sending heath check
>>> queries to the vdsm.
>>> Power management will try to reboot a host when the health checks to
>>> vdsm will not be answered.
>>> So... if engine gets no reply and has no way of rebooting the host, the
>>> host status will be changed to Non-Responsive and the vm's will be
>>> unknown because engine has no way of knowing what's happening with the
>>> vm's.
>>> Since reboot of the host will kill the vm's running on it - this will
>>> never cause any vm migration but... along with the High-Availability vm
>>> feature, you will be able to have some of the vm's re-started on the
>>> second host after the host reboot (and that is only if Power Management
>>> was confirmed as successful).
>>>
>>> VM migration is only triggered when:
>>> 1. Cluster configuration states that the vm should be migrated in case
>>> of failure
>>> 2. Engine has access to the host - so the failure is on the storage
>>> side
>>> and not the host side.
>>> 3. the vms are not actively writing (although there might be a new RFE
>>> for it).
>>>
>>> hope this clears things up
>>>
>>> Dafna
>>>
>>>
>>>
>>> On 01/27/2014 10:11 AM, Andrew Lau wrote:
>>>> Hi,
>>>>
>>>> Have you got power management enabled?
>>>>
>>>> That's the fencing feature required for the engine to ensure that
the
>>>> host is actually offline. It won't resume any other VMs to prevent
>>>> potential VM corruption (eg. VM running on multiple hosts).
>>>>
>>>> Andrew.
>>>>
>>>> On Jan 27, 2014 5:12 PM, "Jaison peter"
<urotrip2(a)gmail.com
>>>> <mailto:urotrip2@gmail.com>> wrote:
>>>>
>>>> Hi all ,
>>>>
>>>> I was setting a two node ovirt cluster with ovirt engine on
>>>> seperate node . I completed the configuration and tested VM live
>>>> migrations with out any issues . Then for checking cluster HA I
>>>> powered down one host and expected vms running on that host to be
>>>> migrated to the other one . But nothing happened , Engine
>>>> detected
>>>> host as un-rechable and marked it as non-operational and vm
>>>> ran on
>>>> that host went to 'unknown state' . Is that not possible to
setup
>>>> a fully HA ovirt cluster with two nodes ? or else is that my
>>>> configuration problem ? please advice .
>>>>
>>>> Thanks & Regards
>>>>
>>>> Alex
>>>>
>>>> _______________________________________________
>>>> Users mailing list
>>>> Users(a)ovirt.org <mailto:Users@ovirt.org>
>>>> http://lists.ovirt.org/mailman/listinfo/users
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> Users mailing list
>>>> Users(a)ovirt.org
>>>> http://lists.ovirt.org/mailman/listinfo/users
>>>
>>> --
>>> Dafna Ron
>>> _______________________________________________
>>> Users mailing list
>>> Users(a)ovirt.org
>>> http://lists.ovirt.org/mailman/listinfo/users
>>
>>
>
>
_______________________________________________
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18 comments
6 participants
participants (6)
-
Andrew Lau -
Dafna Ron -
Eli Mesika -
Jaison peter -
Karli Sjöberg -
Tareq Alayan