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Bug 2120757

Summary:	[17.0 ga tech preview] Image pre-caching
Product:	Red Hat OpenStack	Reporter:	Artom Lifshitz <alifshit>
Component:	openstack-nova	Assignee:	OSP DFG:Compute <osp-dfg-compute>
Status:	CLOSED CURRENTRELEASE	QA Contact:	OSP DFG:Compute <osp-dfg-compute>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	17.0 (Wallaby)	CC:	dasmith, eglynn, igallagh, jhakimra, kchamart, sbauza, sgordon, vromanso
Target Milestone:	ga	Keywords:	Triaged
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	Technology Preview
Doc Text:	In Red Hat OpenStack Platform 17.0, a technology preview is available for requesting that images are pre-cached on Compute nodes in a host aggregate, when using microversion 2.81. To reduce boot time, you can request that a group of hosts within an aggregate fetch and cache a list of images.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2022-09-12 15:19:43 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Artom Lifshitz 2022-08-23 16:50:17 UTC

This bug was initially created as a copy of Bug #1763839

I am copying this bug because: 

Tech preview release note because lack of QE capacity.

Support image pre-caching on compute nodes as requested via the API.

Upstream spec: 

https://specs.openstack.org/openstack/nova-specs/specs/ussuri/approved/image-precache-support.html

Procedure for QE will be:

0. Set image_cache_manager_interval to something short like 10m for compute nodes
1. Set up a deployment with multiple compute nodes not using Ceph
2. Create an aggregate around multiple compute nodes
3. Request some image be pre-cached on that aggregate (openstack aggregate cache images)
4. Check logs on compute nodes to confirm (grep for 'Caching.*request' in compute logs. Check for errors around that time. Note timestamp on base image in $nova/instances/_base.
5. Re-request the same image, check that compute logs indicate that the image is already cached. Check base image file timestamp to ensure it has been updated.
6. Ensure that requesting the image be cached keeps the cache manager from removing it, and that it *is* removed once the cache manager runs after $interval time has passed since the last cache request.

Comment 1 Artom Lifshitz 2022-09-12 15:19:43 UTC

The release notes automation will pick up BZs with the right flags even if they're closed. With the doc text done and requires_doc_text set to +, we can close this.