Design #6517: Schedule Skip Immediately Config

[kaovilai]

Design to add new skipImmediately to schedule spec and related CLI flags for server, install, etc. to allow immediately due run to be skipped.

Thank you for contributing to Velero!

Please add a summary of your change

Does your change fix a particular issue?

For #6517

Please indicate you've done the following:

• Accepted the DCO. Commits without the DCO will delay acceptance.
• Created a changelog file or added /kind changelog-not-required as a comment on this pull request.
• Updated the corresponding documentation in site/content/docs/main.

Implementation: #7169

[kaovilai]

/kind changelog-not-required

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (5cbfd9f) 61.75% compared to head (bf3efc3) 61.94%.
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6829      +/-   ##
==========================================
+ Coverage   61.75%   61.94%   +0.18%     
==========================================
  Files         259      259              
  Lines       27894    27903       +9     
==========================================
+ Hits        17227    17285      +58     
+ Misses       9459     9410      -49     
  Partials     1208     1208              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[draghuram]

Proposal looks good to me though I would have preferred trigger to be false by default. By far, that is the most intuitive and least surprising.

[kaovilai]

I don't mind moving it to false by default if community agrees.

Just didn't wanna break anyone relying on this.. but to be fair this will go in a new minor version so probably enough to make note of the changes.

[kaovilai]

After looking at the code.. I think saying schedule unpause always cause backup to trigger is inaccurate.

To be more precise, the following code is used, based on last backup time to generate if it needs to run after unpausing.

func getNextRunTime(schedule *velerov1.Schedule, cronSchedule cron.Schedule, asOf time.Time) (bool, time.Time) {
	var lastBackupTime time.Time
	if schedule.Status.LastBackup != nil {
		lastBackupTime = schedule.Status.LastBackup.Time
	} else {
		lastBackupTime = schedule.CreationTimestamp.Time
	}

	nextRunTime := cronSchedule.Next(lastBackupTime)

	return asOf.After(nextRunTime), nextRunTime
}

So perhaps it would take note when unpause happens (added to ScheduleStatus struct), and then if --unpause-triggers=false and unpause timestamp says less than a second ago, it will generate next run time based on unpauseTimestamp rather than

	nextRunTime := cronSchedule.Next(lastBackupTime)

[kaovilai]

Switched out added ScheduleStatus field from LastUnpaused to LastSkipped as that is more practical and more useful.

[kaovilai]

technically this already went in via #7169