3:52 p.m.
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Hi Yaniv,
Thanks for your detailed reply, it's very much appreciated.
On 5 Jan 2018, at 8:34 pm, Yaniv Kaul <ykaul(a)redhat.com>
wrote:
=20
Indeed, greenfield deployment has its advantages.
=20
The down side to that is juggling iSCSI LUNs, I'll have to migrate VMs =
on
XenServer off one LUN at a time, remove that LUN from XenServer and =
add it to oVirt as new storage, and continue - but if it's what has to =
be done, we'll do it.
=20
The migration of VMs has three parts:
- VM configuration data (from name to number of CPUs, memory, etc.)
That's not too much of an issue for us, we have a pretty standard set of =
configuration for performance / sizing.
- Data - the disks themselves.
This is the big one, for most hosts at least the data is on a dedicated =
logical volume, for example if it's postgresql, it would be LUKS on top =
of a logical volume for /var/lib/pgsql etc....
- Adjusting VM internal data (paths, boot kernel, grub?, etc.)
Everything is currently PVHVM which uses standard grub2, you could =
literally dd any one of our VMs to a physical disk and boot it in any =
x86/64 machine.
The first item could be automated. Unfortunately, it was a bit of a =
challenge to find a common automation platform. For example, we have =
great Ansible support, which I could not find for XenServer (but[1], =
which may be a bit limited). Perhaps if there aren't too many VMs, this =
could be done manually. If you use Foreman, btw, then it could probably =
be used for both to provision?
The 2nd - data movement could be done in at least two-three ways:
1. Copy using 'dd' from LUN/LV/raw/? to a raw volume in oVirt.
2. (My preferred option), copy using 'dd' from LUN/LV/raw and upload =
using the oVirt upload API (example in Python[2]). I think that's an =
easy to implement option and provides the flexibility to copy from =
pretty much any source to oVirt.
A key thing here would be how quickly the oVirt API can ingest the data, =
our storage LUNs are 100% SSD each LUN can easily provide at least =
1000MB/s and around 2M 4k write IOP/s and 2-4M 4k read IOP/s so we =
always find hypervisors disk virtualisation mechanisms to be the =
bottleneck - but adding an API to the mix, especially one that is single =
threaded (if that does the data stream processing) could be a big =
performance problem.
3. There are ways to convert XVA to qcow2 - I saw some references on
=
the Internet, never tried any.
This is something I was thinking of potentially doing, I can actually =
export each VM as an OVF/OVA package - since that's very standard I'm =
assuming oVirt can likely import them and convert to qcow2 or raw/LVM?
=20
As for the last item, I'm really not sure what changes are needed, if =
at all.
I don't know the disk convention, for example (/dev/sd* for SCSI =
disk -> virtio-scsi, but are there are other device types?)
Xen's virtual disks are all /dev/xvd[a-z]
Thankfully, we partition everything as LVM and partitions (other than =
boot I think) are mounted as such.
=20
I'd be happy to help with any adjustment needed for the Python script =
below.
Very much appreciated, when I get to the point where I'm happy with the =
basic architectural design and POC deployment of oVirt - that's when =
I'll be testing importing VMs / data in various ways and have made note =
of these scripts.
=20
Y.
=20
[1] http://docs.ansible.com/ansible/latest/xenserver_facts_module.html =
<http://docs.ansible.com/ansible/latest/xenserver_facts_module.html>
[2] =
https://github.com/oVirt/ovirt-engine-sdk/blob/master/sdk/examples/upload_=
disk.py =
<https://github.com/oVirt/ovirt-engine-sdk/blob/master/sdk/examples/upload=
_disk.py>
=20
--Apple-Mail=_35F8DEE9-967F-4EC8-8537-CA22EDA2D86A
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<html><head><meta http-equiv=3D"Content-Type"
content=3D"text/html; =
charset=3Dus-ascii"></head><body style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; line-break: after-white-space;" class=3D"">Hi
=
Yaniv,<div class=3D""><br class=3D""></div><div
class=3D"">Thanks for =
your detailed reply, it's very much appreciated.</div><div
class=3D""><br =
class=3D""></div><div
class=3D""><div><blockquote type=3D"cite" =
class=3D""><div class=3D"">On 5 Jan 2018, at 8:34 pm, Yaniv
Kaul <<a =
href=3D"mailto:ykaul@redhat.com"
class=3D"">ykaul(a)redhat.com</a>&gt; =
wrote:</div><br class=3D"Apple-interchange-newline"><div
class=3D""><div =
class=3D"gmail_quote" style=3D"font-family: Helvetica; font-size: 13px; =
font-style: normal; font-variant-caps: normal; font-weight: normal; =
letter-spacing: normal; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px;"><div class=3D"">Indeed,
greenfield =
deployment has its advantages.</div><blockquote class=3D"gmail_quote"
=
style=3D"margin: 0px 0px 0px 0.8ex; border-left-width: 1px; =
border-left-style: solid; border-left-color: rgb(204, 204, 204); =
padding-left: 1ex;"><div style=3D"word-wrap: break-word;"
class=3D""><div =
class=3D""><div class=3D""><br
class=3D""></div><div class=3D"">The down =
side to that is juggling iSCSI LUNs, I'll have to migrate VMs on =
XenServer off one LUN at a time, remove that LUN from XenServer and add =
it to oVirt as new storage, and continue - but if it's what has to be =
done, we'll do it.</div></div></div></blockquote><div
class=3D""><br =
class=3D""></div><div class=3D"">The migration of VMs
has three =
parts:</div><div class=3D"">- VM configuration data (from name to
number =
of CPUs, memory,
etc.)</div></div></div></blockquote><div><br =
class=3D""></div><div>That's not too much of an issue for us,
we have a =
pretty standard set of configuration for performance / sizing.</div><br =
class=3D""><blockquote type=3D"cite"
class=3D""><div class=3D""><div =
class=3D"gmail_quote" style=3D"font-family: Helvetica; font-size: 13px; =
font-style: normal; font-variant-caps: normal; font-weight: normal; =
letter-spacing: normal; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px;"><div class=3D"">- Data - the
disks =
themselves.</div></div></div></blockquote><div><br =
class=3D""></div><div>This is the big one, for most hosts at
least the =
data is on a dedicated logical volume, for example if it's postgresql, =
it would be LUKS on top of a logical volume for /var/lib/pgsql =
etc....</div><br class=3D""><blockquote type=3D"cite"
class=3D""><div =
class=3D""><div class=3D"gmail_quote" style=3D"font-family:
Helvetica; =
font-size: 13px; font-style: normal; font-variant-caps: normal; =
font-weight: normal; letter-spacing: normal; text-align: start; =
text-indent: 0px; text-transform: none; white-space: normal; =
word-spacing: 0px; -webkit-text-stroke-width: 0px;"><div
class=3D"">- =
Adjusting VM internal data (paths, boot kernel, grub?, =
etc.)</div></div></div></blockquote><div><br =
class=3D""></div><div>Everything is currently PVHVM which uses
standard =
grub2, you could literally dd any one of our VMs to a physical disk and =
boot it in any x86/64 machine.</div><br class=3D""><blockquote =
type=3D"cite" class=3D""><div class=3D"gmail_quote"
style=3D"font-family: =
Helvetica; font-size: 13px; font-style: normal; font-variant-caps: =
normal; font-weight: normal; letter-spacing: normal; text-align: start; =
text-indent: 0px; text-transform: none; white-space: normal; =
word-spacing: 0px; -webkit-text-stroke-width: 0px;"><div
class=3D"">The =
first item could be automated. Unfortunately, it was a bit of a =
challenge to find a common automation platform. For example, we have =
great Ansible support, which I could not find for XenServer (but[1], =
which may be a bit limited). Perhaps if there aren't too many VMs, this =
could be done manually. If you use Foreman, btw, then it could probably =
be used for both to provision?</div><div class=3D"">The 2nd - data
=
movement could be done in at least two-three ways:</div><div
class=3D"">1.=
Copy using 'dd' from LUN/LV/raw/? to a raw volume in oVirt.</div><div =
class=3D"">2. (My preferred option), copy using 'dd' from LUN/LV/raw
and =
upload using the oVirt upload API (example in Python[2]). I think that's =
an easy to implement option and provides the flexibility to copy from =
pretty much any source to
oVirt.</div></div></blockquote><div><br =
class=3D""></div><div>A key thing here would be how quickly the
oVirt =
API can ingest the data, our storage LUNs are 100% SSD each LUN can =
easily provide at least 1000MB/s and around 2M 4k write IOP/s and 2-4M =
4k read IOP/s so we always find hypervisors disk virtualisation =
mechanisms to be the bottleneck - but adding an API to the mix, =
especially one that is single threaded (if that does the data stream =
processing) could be a big performance problem.</div><br =
class=3D""><blockquote type=3D"cite"
class=3D""><div class=3D"gmail_quote"=
style=3D"font-family: Helvetica; font-size: 13px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><div =
class=3D"">3. There are ways to convert XVA to qcow2 - I saw some =
references on the Internet, never tried =
any.</div></div></blockquote><div><br
class=3D""></div><div>This is =
something I was thinking of potentially doing, I can actually export =
each VM as an OVF/OVA package - since that's very standard I'm assuming =
oVirt can likely import them and convert to qcow2 or raw/LVM?</div><br =
class=3D""><blockquote type=3D"cite"
class=3D""><div class=3D"gmail_quote"=
style=3D"font-family: Helvetica; font-size: 13px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><div =
class=3D""><br class=3D""></div><div
class=3D"">As for the last item, =
I'm really not sure what changes are needed, if at all. I don't know the =
disk convention, for example (/dev/sd* for SCSI disk -> virtio-scsi, =
but are there are other device
types?)</div></div></blockquote><div><br =
class=3D""></div><div>Xen's virtual disks are all =
/dev/xvd[a-z]</div><div>Thankfully, we partition everything as LVM and =
partitions (other than boot I think) are mounted as such.</div><br =
class=3D""><blockquote type=3D"cite"
class=3D""><div class=3D"gmail_quote"=
style=3D"font-family: Helvetica; font-size: 13px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><div =
class=3D""><br class=3D""></div><div
class=3D"">I'd be happy to help =
with any adjustment needed for the Python script =
below.</div></div></blockquote><div><br
class=3D""></div><div>Very much =
appreciated, when I get to the point where I'm happy with the basic =
architectural design and POC deployment of oVirt - that's when I'll be =
testing importing VMs / data in various ways and have made note of these =
scripts.</div><br class=3D""><blockquote type=3D"cite"
class=3D""><div =
class=3D"gmail_quote" style=3D"font-family: Helvetica; font-size: 13px; =
font-style: normal; font-variant-caps: normal; font-weight: normal; =
letter-spacing: normal; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px;"><div class=3D""><br
class=3D""></div><div=
class=3D"">Y.</div><div class=3D""><br
class=3D""></div><div =
class=3D"">[1] <a =
href=3D"http://docs.ansible.com/ansible/latest/xenserver_facts_modul...
" =
class=3D"">http://docs.ansible.com/ansible/latest/xenserver_...
tml</a></div><div class=3D"">[2] <a =
href=3D"https://github.com/oVirt/ovirt-engine-sdk/blob/master/sdk/ex...
/upload_disk.py" =
class=3D"">https://github.com/oVirt/ovirt-engine-sdk/blob/ma...
les/upload_disk.py</a></div><div =
class=3D""> </div></div></blockquote></div><br
=
class=3D""></div></body></html>=
--Apple-Mail=_35F8DEE9-967F-4EC8-8537-CA22EDA2D86A--