--Apple-Mail=_35F8DEE9-967F-4EC8-8537-CA22EDA2D86A Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii Hi Yaniv, Thanks for your detailed reply, it's very much appreciated.
On 5 Jan 2018, at 8:34 pm, Yaniv Kaul <ykaul@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.)
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 =
3. There are ways to convert XVA to qcow2 - I saw some references on =
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. 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. 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 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=us-ascii <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@redhat.com</a>> = 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_module.html= " = class=3D"">http://docs.ansible.com/ansible/latest/xenserver_facts_module.h= tml</a></div><div class=3D"">[2] <a = href=3D"https://github.com/oVirt/ovirt-engine-sdk/blob/master/sdk/examples= /upload_disk.py" = class=3D"">https://github.com/oVirt/ovirt-engine-sdk/blob/master/sdk/examp= 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--