4:48 p.m.
----- Original Message -----
From: "Liron Aravot" <laravot(a)redhat.com>
To: "Michael Kublin" <mkublin(a)redhat.com>
Cc: engine-devel(a)ovirt.org
Sent: Monday, November 19, 2012 3:58:55 PM
Subject: Re: [Engine-devel] [Engine-Devel] OvfDataUpdater
----- Original Message -----
> From: "Michael Kublin" <mkublin(a)redhat.com>
> To: "Liron Aravot" <laravot(a)redhat.com>
> Cc: engine-devel(a)ovirt.org
> Sent: Monday, November 19, 2012 3:44:41 PM
> Subject: Re: [Engine-devel] [Engine-Devel] OvfDataUpdater
>
>
>
> ----- Original Message -----
> > From: "Liron Aravot" <laravot(a)redhat.com>
> > To: "Michael Kublin" <mkublin(a)redhat.com>
> > Cc: engine-devel(a)ovirt.org
> > Sent: Monday, November 19, 2012 3:34:11 PM
> > Subject: Re: [Engine-devel] [Engine-Devel] OvfDataUpdater
> >
> >
> >
> > ----- Original Message -----
> > > From: "Michael Kublin" <mkublin(a)redhat.com>
> > > To: "Liron Aravot" <laravot(a)redhat.com>
> > > Cc: engine-devel(a)ovirt.org
> > > Sent: Monday, November 19, 2012 3:28:06 PM
> > > Subject: Re: [Engine-devel] [Engine-Devel] OvfDataUpdater
> > >
> > >
> > >
> > > ----- Original Message -----
> > > > From: "Liron Aravot" <laravot(a)redhat.com>
> > > > To: "Michael Kublin" <mkublin(a)redhat.com>
> > > > Cc: engine-devel(a)ovirt.org
> > > > Sent: Monday, November 19, 2012 3:17:04 PM
> > > > Subject: Re: [Engine-devel] [Engine-Devel] OvfDataUpdater
> > > >
> > > >
> > > >
> > > > ----- Original Message -----
> > > > > From: "Michael Kublin" <mkublin(a)redhat.com>
> > > > > To: "Liron Aravot" <laravot(a)redhat.com>
> > > > > Cc: engine-devel(a)ovirt.org
> > > > > Sent: Monday, November 19, 2012 3:03:23 PM
> > > > > Subject: Re: [Engine-devel] [Engine-Devel] OvfDataUpdater
> > > > >
> > > > >
> > > > >
> > > > > ----- Original Message -----
> > > > > > From: "Liron Aravot" <laravot(a)redhat.com>
> > > > > > To: "Mike Kolesnik" <mkolesni(a)redhat.com>
> > > > > > Cc: engine-devel(a)ovirt.org, "Michael Kublin"
> > > > > > <mkublin(a)redhat.com>
> > > > > > Sent: Monday, November 19, 2012 2:52:56 PM
> > > > > > Subject: Re: [Engine-devel] [Engine-Devel] OvfDataUpdater
> > > > > >
> > > > > >
> > > > > >
> > > > > > ----- Original Message -----
> > > > > > > From: "Mike Kolesnik"
<mkolesni(a)redhat.com>
> > > > > > > To: "Liron Aravot"
<laravot(a)redhat.com>
> > > > > > > Cc: engine-devel(a)ovirt.org, "Michael
Kublin"
> > > > > > > <mkublin(a)redhat.com>
> > > > > > > Sent: Monday, November 19, 2012 2:44:56 PM
> > > > > > > Subject: Re: [Engine-devel] [Engine-Devel]
> > > > > > > OvfDataUpdater
> > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > ----- Original Message -----
> > > > > > > > > From: "Liron Aravot"
<laravot(a)redhat.com>
> > > > > > > > > To: engine-devel(a)ovirt.org
> > > > > > > > > Sent: Monday, November 19, 2012 2:03:57 PM
> > > > > > > > > Subject: [Engine-devel] [Engine-Devel]
> > > > > > > > > OvfDataUpdater
> > > > > > > > >
> > > > > > > > > starting a new discussion thread.
> > > > > > > > >
> > > > > > > > > ----- Original Message -----
> > > > > > > > > > From: "Mike Kolesnik"
<mkolesni(a)redhat.com>
> > > > > > > > > > To: "Liron Aravot"
<laravot(a)redhat.com>
> > > > > > > > > > Sent: Monday, November 19, 2012
12:42:10 PM
> > > > > > > > > > Subject: Re: [Engine-devel]
OvfAutoUpdater
> > > > > > > > > >
> > > > > > > > > > I think 'version' is a more
standard term for the
> > > > > > > > > > column
> > > > > > > > > > names.
> > > > > > > > > >
> > > > > > > > > > Also in: 4. If succesfull - for each
vm update
> > > > > > > > > > the
> > > > > > > > > > ovf_generation
> > > > > > > > > > to
> > > > > > > > > > equal the db_generation.
> > > > > > > > > > I think you mean that the update should
be to the
> > > > > > > > > > entity
> > > > > > > > > > version
> > > > > > > > > > you
> > > > > > > > > > initially selected.
> > > > > > > > > >
> > > > > > > > 1. I think should be version = version +1;
> > > > > > the version will be the db_generation that was loaded
> > > > > > when
> > > > > > we
> > > > > > loaded
> > > > > > the vm/template.
> > > > > > for example - if the vm/template was updated twice
> > > > > > between
> > > > > > OvfUpdater
> > > > > > runs, we will need to increment twice - so incrementing
> > > > > > by
> > > > > > one
> > > > > > will
> > > > > > cause another unneeded ovf update for that vm.
> > > > > I am talking about ovfVersion or how you called it.
> > > > me too,
> > > > if we update the vm three times between OvfAutoUpdater runs ,
> > > > we
> > > > will
> > > > have the following values in the loaded vm for example:
> > > > db_generation 8
> > > > ovf_generation 5
> > > >
> > > > when we perform the ovf update , ovf_generation should be set
> > > > to
> > > > 8
> > > > and not to 6, as version '8' is the version that we wrote
the
> > > > ovf
> > > > metadata of.
> > > These should be written in wiki, with remarks that values which
> > > were
> > > retrieved
> > > from DB together.
> > > > > > > > 2. Now the quartz is automatic process,
updateVmInSpm
> > > > > > > > it
> > > > > > > > is
> > > > > > > > spm
> > > > > > > > operation -it means it can trigger a reconstruct
> > > > > > > > and spm election.
> > > > > > 2. updateVmInSpm command would be changed so it won't
> > > > > > trigger
> > > > > > failover, will add that to the wiki.
> > > > > > > > 3. How your solution is handling a case of
> > > > > > > > hotPlug/hotUnplug/remove/add of vm disks.
vm_static
> > > > > > > > is
> > > > > > > > not
> > > > > > > > usually
> > > > > > > > updated.
> > > > > > Whenever will be a command that locks a vm/template, you
> > > > > > will
> > > > > > have
> > > > > > an
> > > > > > option during the unlock to specify if the version need
> > > > > > to
> > > > > > be
> > > > > > incremented, you'll be able to increment it also
> > > > > > yourself.
> > > > > > The HotUnPlug command does lock the vm and during
> > > > > > endSuccesfully
> > > > > > attempt to update the vm in spm, so it will increment the
> > > > > > db_version/generation instead.
> > > > > > >
> > > > > addDisk, removeDisk, hotPlug/unPlug not locking a vm.
> > > > > Also, as far as I know LockVm/UnLockVm it is operation on
> > > > > vm_dynamic
> > > > > and not
> > > > > vm_static.
> > > >
> > > > hotplug acquires memory lock on the vm and has no async tasks
> > > > if
> > > > I
> > > > recall correctly.
> > > Yes, correct and what? These what I said, vm_static is not
> > > updated.
> > you will just call the dao method for incrementing the
> > db_generation,
> > you don't have to perform vm_static update.
> > > > adddisk acquires shared lock on the vm which is problematic
> > > > with
> > > > today flow as well - as you have a race during updateVmInSpm,
> > > > it
> > > > should be fixed regardless of the OvfAutoUpdater.
> > > It is not answer on my question. How ovf will be updated? How
> > > you
> > > understand
> > > that ovf of vm should be updated?
> >
> > the ovf will be updated when you increment the db_generation
> > value
> > instead of calling updateVmInSpm().
> > you will be able to do that from the dao directly when you want,
> > or
> > when you unlock a vm/template.
> > when you will update the db_generation, the vm/template would be
> > picked up by OvfUpdater as it's db_generation is different than
> > its
> > ovf_generation.
> 1. Update of ovfs is not related to locks and it should not be, I
> don't understand why
> you link them.
> 2. Races - your automatic process and couple of add disk commands.
> You will miss update
> of ovf.
> 3. Also when you will add increase of generation it is not clear
> from
> your design
1+2 The OvfAutoUpdater is not related and doesn't acquire any locks.
as of today, if you call updateVmInSpm without performing the
operations with lock on the vm you'll have a race - for example, in
Liron,
updateVmInSpm is called at endSuccessfully, you can not build on locks,
especially on in memory locks.
addDisk (shared calls, two updateVmInSpm might be executed in the
same time and you can't know with with ovf you'll end).
therefore, when updating the ovf_generation you should have a lock
somewhere otherwise you might miss updates because of races.
if today updatevminspm is called without locks and have races, it
needs to be fixed unrelated to it.
Liron, you should fix these. These is a new
development, it should fix
all known bugs and problems and not introduce a new ones
3. you will increase the generation whenever you made updateVmInSpm.
> > > > >
> > > > > > > Also consider snapshots & vNICs which affect the
VM
> > > > > > > state.
> > > > > > Whatever affect the vm state and triggers updateVmInSpm
> > > > > > today
> > > > > > will
> > > > > > continue to, it can be added to flows which don't do
that
> > > > > > today.
> > > > > > >
> > > > > > > > 4. Reconstruct/Recovery - updateVmInSpm should
be
> > > > > > > > called
> > > > > > > > on
> > > > > > > > all
> > > > > > > > vms,
> > > > > > > > no matter if they were updated.
> > > > > >
> > > > > > Ofcourse, it's being taken care of.
> > > > > How?
> > > > we don't have ovf's of the vms when we reconstruct as we
> > > > don't
> > > > have
> > > > master domain - so we should set the ovf_generation of the
> > > > vms
> > > > to
> > > > be
> > > > 0 - which will cause ovfautoupdater to copy the vm metadata.
> > > I did not understand that statement and how it is related.
> > OvfAutoUpdater will get those vms for update as db_generation is
> > different than ovf_generation.
> > > > a performance improvement may be introduced later on in case
> > > > of
> > > > wrong
> > > > master version, but that's not related to the ovfautoupdater.
> > > I don't understand connection to performance.
> > > Now you are replacing a calls to VmCommand.updateVmInSpm() one
> > > of
> > > them it
> > > is at reconstruct flow, and you should handle it also and add
> > > it
> > > to
> > > wiki.
> > answered below, OvfAutoUpdater will get those vms for update as
> At reconstruct all vms are updated. So it is not related to
> generation.
> How you handle these case?
when doing reconstruct, the ovf_generation of all vms is set to 0 as
we don't have them on the master domain.
ovfupdater will get this vms for update as ovf_generation <
db_generation, will copy the vm ovf and set db_genertion to
ovf_generation.
> > db_generation is different than ovf_generation.
> > > > > > > >
> > > > > > > > > > Regards,
> > > > > > > > > > Mike
> > > > > > > > > >
> > > > > > > > > > ----- Original Message -----
> > > > > > > > > > >
http://wiki.ovirt.org/wiki/Feature/OvfAutoUpdater
> > > > > > > > > > >
> > > > > > > > > > > Hi all, i'll be glad if you
could review the
> > > > > > > > > > > wiki
> > > > > > > > > > > page
> > > > > > > > > > > of
> > > > > > > > > > > OvfAutoUpdater, if you have any
suggestions or
> > > > > > > > > > > ideas
> > > > > > > > > > > please
> > > > > > > > > > > let
> > > > > > > > > > > me
> > > > > > > > > > > know.
> > > > > > > > > > >
> > > > > > > > > > >
http://wiki.ovirt.org/wiki/Feature/OvfAutoUpdater
> > > > > > > > > > >
> > > > > > > > > > > short preview from the wiki:
> > > > > > > > > > > vm/template configurations
(including disks
> > > > > > > > > > > info)
> > > > > > > > > > > are
> > > > > > > > > > > stored
> > > > > > > > > > > on
> > > > > > > > > > > the
> > > > > > > > > > > master storage domain for backup
purposes,
> > > > > > > > > > > import/export
> > > > > > > > > > > and
> > > > > > > > > > > also
> > > > > > > > > > > to
> > > > > > > > > > > provide the abillity to run VMs
without having
> > > > > > > > > > > a
> > > > > > > > > > > running
> > > > > > > > > > > engine/db.
> > > > > > > > > > > Currently ovf update is done
synchronously when
> > > > > > > > > > > performing
> > > > > > > > > > > various
> > > > > > > > > > > operations on vms/templates -
update, save,
> > > > > > > > > > > adding/removing
> > > > > > > > > > > a
> > > > > > > > > > > disk,
> > > > > > > > > > > etc. What's more, currently
updating the ovf
> > > > > > > > > > > (updateVM
> > > > > > > > > > > vdsm
> > > > > > > > > > > call)
> > > > > > > > > > > is
> > > > > > > > > > > usually done within a
transcation.
> > > > > > > > > > >
> > > > > > > > > > > The idea behined OvfAutoUpdater is
to perform
> > > > > > > > > > > batch
> > > > > > > > > > > ovf
> > > > > > > > > > > update
> > > > > > > > > > > operations that aggregate all
outstanding
> > > > > > > > > > > updates
> > > > > > > > > > > per
> > > > > > > > > > > data
> > > > > > > > > > > center.
> > > > > > > > > > > These updates will be done in
specifed time
> > > > > > > > > > > intervals
> > > > > > > > > > > which
> > > > > > > > > > > will
> > > > > > > > > > > reduce XML-RPC calls and will
enable the
> > > > > > > > > > > removal
> > > > > > > > > > > of
> > > > > > > > > > > this
> > > > > > > > > > > syncronous
> > > > > > > > > > > vdsm call from all over the code.
> > > > > > > > > > >
> > > > > > > > > > > Thanks,
> > > > > > > > > > > Liron Aravot.
> > > > > > > > > > >
_______________________________________________
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> > > > > > > > > > >
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> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
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