Allow a VM to be in a state of 'migrating'

[mifrost]

When applying changes, we have regularly received the error Invalid power_state for instance <ID>: MIGRATING , as live migrations occur on instances, preventing any plan / apply operations.

This change adds "migrating" to the list of acceptable states for an instance to be in. See also #428

[jtopjian]

Thanks for submitting this patch.

Can you explain in more detail why someone would want to make a change when an instance is in the middle of migrating? My initial impression is that this kind of error is actually a good thing.

[mifrost]

@jtopjian No problem

In our case it's because terraform will try to refresh the state of all instances before every plan action. This means that even if there are no changes to make to the migrating instance, the whole action will still fail.

Even if we attempt to avoid the problem with a -target, we still hit it due to a shared dependency as we've used a count parameter.

[jtopjian]

@mifrost OK, that makes sense.

So perhaps instead of having migrating as a valid input (line 356) how about we just let it be a valid status (such as how "error" is being used). Thoughts?

[theopenlab-ci]

Build succeeded.

• terraform-provider-openstack-unittest : SUCCESS in 2m 49s
• terraform-provider-openstack-acceptance-test : SUCCESS in 1h 58m 14s

[mifrost]

@jtopjian very good point - I've updated the PR

[theopenlab-ci]

Build succeeded.

• terraform-provider-openstack-unittest : SUCCESS in 2m 28s
• terraform-provider-openstack-acceptance-test : SUCCESS in 1h 50m 08s

[jtopjian]

@mifrost This looks good to me. Have you been able to validate this change in your environment? It's a little hard for me to reproduce a case where this would be triggered.

[mifrost]

@jtopjian yes - I've used this branch to work around the issue we were seeing

[jtopjian]

LGTM - thank you!