Difference between revisions of "InstanceMigration"

Revision as of 23:31, 17 February 2013

• Launchpad Entry: NovaSpec:migration
• Created: 2010-09-01
• Contributors: JesseAndrews

Summary

Develop a feature to allow cloud administrators to perform maintenance tasks of physical servers. This feature will allow admins to shutdown an instance and move it to a new host node.

Release Note

An internal admin tool to move instances from a compute node has been added to OpenStack compute.

Rationale

Hardware fails. A user's instance shouldn't be permanently lost when hardware must be removed from the pool.

User stories

A member of the operations team notices that the hardware on a server is failing. To protect the users, the instances are migrated and the system is sent to the datacenter team.

Assumptions

• more than one node exists
• compute nodes are able to rsync/scp between each other (server setup should be limited ssh between nodes to only rsync) -- or the image is moved to the object store.

Implementation

a nova-manage command will be added that:

• shutdown the instance
• determines a new server to migrate the instance (via the scheduler)
• the compute node that receives the run command retrieves the image from the existing server.
• the network configuration is kept the same, and the new VM is restarted

Optimization:

• when you take a snapshot, it creates a base and a delta (cow) file
• the base snapshot could be copied before the instance is shutdown, then the delta (cow) could be moved after shutdown - which would be much smaller and faster.
• potentially pause VM instead of shutdown

Test/Demo Plan