OpenStack Compute (Nova)

Add pre-caching to nova image cache management

Registered by Michael Still on 2012-02-11

This blueprint continues on from https://blueprints.launchpad.net/nova/+spec/nova-image-cache-management and adds the pre-caching of popular images. That specification is found under the previous blueprint.

Features to implement:

Faster startup for instances
=================

This should consider the relative popularity of various images (which can be done now without a call to glance). The original specification also considers that cloud hosts might want to have their own images load as fast as possible, but not care so much about pre-caching user uploaded images.

Resiliance to glance failure
================

Some way of designating images as being "mission critical" so that they're pre-cached. This way, if glance is offline an instance can still be started. This designation needs to avoid calling into glance as much as possible.

Schedule new instances on nodes which already have the right image
===========================================

Instance startup will be faster if an instance is started on a node which already has the image cached. Its even better if there is already a resized COW target image of the right size on the node as well. Not only will startup be faster, but disk usage will be used across the cluster.

This needs to respect that users almost certainly don't want all instances of a given type on a single compute node, as if that node fails they'd lose all of the instances. There therefore needs to be some sanity checking applied to this code.

Blueprint information

Status:
Complete
Approver:
Vish Ishaya
Priority:
Low
Drafter:
OpenStack DevOps Drivers
Direction:
Needs approval
Assignee:
Michael Still
Definition:
Obsolete
Series goal:
None
Implementation:
Started
Milestone target:
None
Started by
Vish Ishaya on 2012-05-17
Completed by
John Garbutt on 2014-03-20

Related branches

Sprints

Whiteboard

Gerrit topic: https://review.openstack.org/#q,topic:bp/nova-image-cache-management-2,n,z

Addressed by: https://review.openstack.org/7338
    Implement image prefetching in a separate tool.

Unapproved - please re-submit via nova-spec --johnthetubagy (20th March 2014)Gerrit topic: https://review.openstack.org/#q,topic:bp/nova-image-cache-management-2,n,z

Addressed by: https://review.openstack.org/7338
    Implement image prefetching in a separate tool.

Unapproved - please re-submit via nova-spec --johnthetubagy (20th March 2014)

This blueprint is not complete after a good year or so, marking as Obsolete to tidy up the Nova backlog. --johnthetubaguy (20th April 2014)

(?)

Work Items

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