.. _728.play_pause_stop: Play Pause Stop =============== .. admonition:: Does This Change Affect Me? :class: tip Yes if you run Cylc workflows. Overview -------- 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 :term:`scheduler` is running. * When a workflow is paused, no new jobs will be submitted. * When a workflow is stopped the :term:`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 :term:`restart`). If you want to re-run the entire workflow again from the start either: * :ref:`Install a new run`. * Or if you want to keep the data from the old run start a new :term:`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: .. code-block:: bash # remove the workflow database, the work, share and log directories cylc clean --rm .service/db:work:share:log # only remove the worflow database $ cylc clean --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 ----------------------- .. list-table:: :class: grid-table * - - **Cylc 7** - **Rose 2019** - **Cylc 8** (Rose 2) * - Play - :: cylc run - :: rose suite-run - :: cylc play * - Pause - :: cylc hold - :: cylc hold - :: cylc pause * - Resume - :: cylc release - :: cylc release - :: cylc play * - Stop - :: cylc stop - :: rose suite-shutdown - :: cylc stop