Play Pause Stop

Does This Change Affect Me?

Yes if you run Cylc workflows.


Cylc 8 uses a simplified model for controlling workflows based on the controls of a tape player.

There are now three controls, play, pause and stop:

  • When a workflow is playing, the scheduler is running.

  • When a workflow is paused, no new jobs will be submitted.

  • When a workflow is stopped the scheduler is no longer running.

These controls are available in the web GUI or on the command line with the commands:

  • cylc play

  • cylc pause

  • cylc stop

A workflow can be safely played, paused and stopped any number of times without interrupting the workflow.

Re-Running Workflows

The cylc play command will always pick up where it left off (a restart).

If you want to re-run the entire workflow again from the start either:

  • Install a new run.

  • Or if you want to keep the data from the old run start a new flow at the beginning of the graph, and stop the original flow.

It is still possible to re-run workflows in-place in the Cylc 7 manner, however, this is discouraged. To do this remove the workflow database as well as any other evidence of the previous run that is no longer desired:

# remove the workflow database, the work, share and log directories
cylc clean <id> --rm .service/db:work:share:log

# only remove the worflow database
$ cylc clean <id> --rm .service/db

Then restart with cylc play.

Hold & Release

The cylc hold and cylc release commands are still present. These work on individual tasks rather than the workflow as a whole.

Mapping To Old Commands

Cylc 7

Rose 2019

Cylc 8 (Rose 2)


cylc run <id>
rose suite-run
cylc play <id>


cylc hold <id>
cylc hold <id>
cylc pause <id>


cylc release <id>
cylc release <id>
cylc play <id>


cylc stop <id>
rose suite-shutdown
cylc stop <id>