Re: [nova][ptg] Allow compute nodes to use DISK_GB from shared storage RP by using aggregate relationship
On Thu, Nov 14, 2019 at 02:58, "Patil, Tushar" <Tushar.Patil@nttdata.com> wrote:
On 11/13/2019 8:34 AM, Sylvain Bauza wrote:
Me too. To be clear, I don't think operators would modify the above but if so, they would need reshapes.
Maybe not, but this is the kind of detail that should be in the spec and functional tests to make sure it's solid since this is a big architectural change in nova.
It depends on how the aggregates are created on the nova and placement side.
A) From placement point of view, operator can create a new aggregate and add shared storage RP to it (tag MISC_SHARES_VIA_AGGREGATE trait to this RP). The newly created valid UUID would then be set in the config option ``sharing_disk_aggregate`` on the compute node side. This aggregate UUID wouldn't be present in the nova aggregate. so it's not possible to add host to the nova aggregate unless a new aggregate is created on nova side.
B) If nova aggregates are synced to the placement service and say below is the picture:
Nova:
Agg1 - metadata (pinned=True) - host1 - host2
Now, operator adds a new shared storage RP to Agg1 on placement side and then set Agg1 UUID in ``sharing_disk_aggregate`` on compute nodes along with ``using_shared_disk_provider`=True``, then it would add compute node RP to the Agg1 on the placement without any issues but when you want to reverse the configuration, using_shared_disk_provider=False, then it not that straight to remove the host from the placement/nova aggregate because there would be other traits set to compute RPs which could cause those functions stop working.
For me from the sharing disk provider feature perspective the placement aggregate that is needed for the sharing to work, and any kind of nova host aggregate (either synced to placement or not) is independent. The placement aggregate is a must for the feature. On top of that if the operator wants to create a nova host aggregate as well and sync it to placement then at the end there will be two, independent placement aggregates. One to express the sharing relationship and one to express a host aggregate from nova. These two aggregate will not be the same as the first one will have the sharing provider in it while the second one doesn't. gibi
We had same kind of discussion [1] when implementing forbidden aggregates where we want to sync traits set to the aggregates but later it was concluded that operator will do it manually.
I will include the details Matt has pointed out in this email in my next patchset.
[1] : http://lists.openstack.org/pipermail/openstack-discuss/2019-June/006950.html
Regards, tpatil
________________________________________ From: Matt Riedemann <mriedemos@gmail.com> Sent: Wednesday, November 13, 2019 11:41 PM To: openstack-discuss@lists.openstack.org Subject: Re: [nova][ptg] Allow compute nodes to use DISK_GB from shared storage RP by using aggregate relationship
On 11/13/2019 8:34 AM, Sylvain Bauza wrote:
Me too. To be clear, I don't think operators would modify the above but if so, they would need reshapes.
Maybe not, but this is the kind of detail that should be in the spec and functional tests to make sure it's solid since this is a big architectural change in nova.
--
Thanks,
Matt
Disclaimer: This email and any attachments are sent in strictest confidence for the sole use of the addressee and may contain legally privileged, confidential, and proprietary data. If you are not the intended recipient, please advise the sender by replying promptly to this email and then delete and destroy this email and any attachments without any further use, copying or forwarding.
On 11/14/2019 1:45 AM, Balázs Gibizer wrote:
For me from the sharing disk provider feature perspective the placement aggregate that is needed for the sharing to work, and any kind of nova host aggregate (either synced to placement or not) is independent. The placement aggregate is a must for the feature. On top of that if the operator wants to create a nova host aggregate as well and sync it to placement then at the end there will be two, independent placement aggregates. One to express the sharing relationship and one to express a host aggregate from nova. These two aggregate will not be the same as the first one will have the sharing provider in it while the second one doesn't.
I tend to agree with the simplicity of this as well. -- Thanks, Matt
For me from the sharing disk provider feature perspective the placement aggregate that is needed for the sharing to work, and any kind of nova host aggregate (either synced to placement or not) is independent. The placement aggregate is a must for the feature. On top of that if the operator wants to create a nova host aggregate as well and sync it to placement then at the end there will be two, independent placement aggregates. One to express the sharing relationship and one to express a host aggregate from nova. These two aggregate will not be the same as the first one will have the sharing provider in it while the second one doesn't.
I tend to agree with the simplicity of this as well.
I have updated the specs as per the agreements at Shanghai PTG. I still do see some thorny issues especially the way disk_gb information will be returned in the new micro-version os-hypervisor API. Please check "other end user impact" and "Response of os-hypervisors statistics" sections from the specs. Please review the specs [1] and give your suggestions/feedback. [1] : https://review.opendev.org/#/c/650188/8 Thanks, tpatil ________________________________________ From: Matt Riedemann <mriedemos@gmail.com> Sent: Thursday, November 14, 2019 11:02 PM To: openstack-discuss@lists.openstack.org Subject: Re: [nova][ptg] Allow compute nodes to use DISK_GB from shared storage RP by using aggregate relationship On 11/14/2019 1:45 AM, Balázs Gibizer wrote:
For me from the sharing disk provider feature perspective the placement aggregate that is needed for the sharing to work, and any kind of nova host aggregate (either synced to placement or not) is independent. The placement aggregate is a must for the feature. On top of that if the operator wants to create a nova host aggregate as well and sync it to placement then at the end there will be two, independent placement aggregates. One to express the sharing relationship and one to express a host aggregate from nova. These two aggregate will not be the same as the first one will have the sharing provider in it while the second one doesn't.
I tend to agree with the simplicity of this as well. -- Thanks, Matt Disclaimer: This email and any attachments are sent in strictest confidence for the sole use of the addressee and may contain legally privileged, confidential, and proprietary data. If you are not the intended recipient, please advise the sender by replying promptly to this email and then delete and destroy this email and any attachments without any further use, copying or forwarding.
participants (3)
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Balázs Gibizer
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Matt Riedemann
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Patil, Tushar