Implementing Guaranteed Start Time

18.0 Miscellaneous > Implementing Guaranteed Start Time

18.6 Implementing Guaranteed Start Time

Guaranteed start time allows you to specify when your environment will start. There are limitations on the number of jobs that can be combined for a guaranteed start time. Also, each job must be a single requirement job. The process of guaranteeing a start time requires that jobs be attached to a virtual container (VC). Only jobs or workflows belonging directly to the VC will be scheduled.

To guarantee start time, do the following:

Create a virtual container (VC).
```
> mvcctl -c
```
Set the holdjobs flag on the VC to prevent jobs from immediately running.
```
> mvcctl -m flags+=holdjobs <VCNAME>
```
Submit the job(s).
```
> msub -W x=vc=<VCNAME> . . .
```
(Optional Step) Specify a start time as epoch or relative (+) via the reqstarttime attribute.
```
> mvcctl -m reqstarttime=<epoch | +{mm:ss}> <VCNAME>
```
Schedule the VC.
```
> mvcctl -x schedulevc <VCNAME>
```
There is a default limit of five jobs that can be combined for guaranteed start time.