Fix vsc backup plugin progress method to not fail on temporary errors

[shubham-pampattiwar]

Fixes vmware-tanzu/velero#7356

[kaovilai]

Suggested change

	p.Log.Warnf("VolumeSnapshotContent has a temporary error %s. SnapshotContent controller will retry later.", errorMessage)
	p.Log.Warnf("VolumeSnapshotContent has a temporary error: %s. SnapshotContent controller will retry later.", errorMessage)

[blackpiglet]

If we don't mark the progress.Completed as true when there is an error in the VSC and VS status, one possible side-effect is that if the error cannot be resolved by retrying, the action will not be completed until the timeout. The default async operation timeout is 4 hours.

[blackpiglet]

Can we add a mechanism to count down the failure limitation?
For example, we can set a max try time for the VSC on error, and put that information in the VSC annotation, then update the error tried number accordingly. Until the limitation is hit, fail the action.

The default async operation sync frequency is 10s. We can introduce a new parameter alongside --item-operation-sync-frequency to set the retry limitation.

[anshulahuja98]

I am not sure how to track for number of errors, since last error might stay same and not be updated.
Might be better to somehow enforce 10min limit and then mark it as failed.

[blackpiglet]

Thanks. A timer is better. Propose the name as item-operation-error-timeout.

The timer should be compared with the VolumeSnapshotContent.Status.Error.Time.

[shubham-pampattiwar]

@blackpiglet @anshulahuja98 the new parameter --item-operation-error-timeout sounds good, will work on a PR for velero controller and then update this PR accordingly.

[anshulahuja98]

this parameter however might lead to more concerns
where each plugin might want to have a different time limit, whereas this is a global setting

[anshulahuja98]

It is better if somehow we give this error exit control to the plugin to be smart enough to exit by it's own logic than a global setting

[blackpiglet]

Just realized I didn't think it through.
It's not possible to have a global timer work in all of the plugins.
item-operation-error-timeout works globally, because it's triggered in the Velero server.

If we don't modify the BIA and RIA interface, we cannot pass the timer to the Progress method.

item-operation-error-timeout can only work in the backup_operations_controllers.go. Looks like that is not what we want to do.

Adding a default timer in the plugin code is the simplest way, but we cannot modify the timer.
Another possible way is adding the Init method just like the ObjectStore and the VolumeSnapshotter plugins.

[shubham-pampattiwar]

@blackpiglet @anshulahuja98 If we add item-operation-error-timeout to backup spec then we can use it in BIA progress method, right ?

[blackpiglet]

@shubham-pampattiwar
That should work.

[anshulahuja98]

I am not sure how to track for number of errors, since last error might stay same and not be updated.
Might be better to somehow enforce 10min limit and then mark it as failed.

[reasonerjt]

I think we can use a hard-coded value for the timeout or max retry, rather than expose a parameter to user to configure.
But given it's the Progress func in the plugin, we need to find a good way to track the time or retry number.