remove schedule validation

[cpanato]

the backup can be created from a schedule in another cluster and when trying to restore that in a new cluster this schedule might not exist, so removing this validation

More context see:

• fixes: In Cluster B allow --from-schedule to reference a schedule created in Cluster A #1168

[carlisia]

lgtm 👍 Thank you!

[skriss]

thanks @cpanato! I tried this out and it works fine as-is: the --from-schedule flag works as long as there is a backup labeled with the schedule name, regardless of whether or not that particular schedule currently exists in the cluster. In the case where no backups exist with the given schedule name as a label, the restore terminates with a phase of FailedValidation.

One small improvement we could make is to replaced the deleted Schedule existence check with a check to see if there are any backups labeled with the schedule name (i.e. do a .List(...) on backups with a label selector on velero.io/schedule-name=<schedule name>). If there are none, we could return an error. This provides more immediate feedback to the CLI user in that scenario. I don't think it's essential, but would be nice and should only require a few lines of code if you're up for it.

[cpanato]

@skriss @ashish-amarnath made the change, please let me know what do you think. thanks again for the review

[skriss]

two minor comments -- LGTM once those are resolved

[skriss]

one other thing - please add a changelog file!

[cpanato]

@skriss done :) ptal

[skriss]

LGTM - @ashish-amarnath please take another look

[skriss]

thanks for the revisions @cpanato!

[ashish-amarnath]

One minor comment about the variable name. It kinda threw me off that we were querying a list of backup objects into a variable called scheduleItems.
My comment was about renaming scheduleItems to backupItems

[cpanato]

@ashish-amarnath done, thanks for the inputs!
@carlisia @skriss PTAL

[ashish-amarnath]

Thanks for working through this @cpanato!