Cylc 8.0b2 Caveats

This is an early release of Cylc, there are some loose ends and features which have not yet been (re)implemented.

The documentation has not been fully reviewed and command line information may be out of date in some cases.

Cylc Flow

Run Numbers

By default when you install a workflow with cylc install it is installed into a numbered subdirectory e.g. run1. A subsequent installation would go into run2, etc.

At present the full workflow registration including this run number must be provided to Cylc commands e.g:

$ cylc play myflow/run1

We plan to infer the most recent run to make this easier e.g:

$ cylc play myflow
CLI Change

We plan to move to a new way of specifying workflow, cycles, tasks and jobs on the command line (with back support for the old format).

This will open up performing operations on multiple workflows in a single command e.g:

$ cylc stop '*'  # stop everything
Platform Selection

When Cylc needs to perform an action on a platform (e.g. submit a job) it picks a random host from the platform. If this host is down the operation will fail.

In a later relase Cylc will pick another host in order to provide resilience to system issues.

Trigger Edit

Functionality removed pending reimplementation.


The new “reflow” functionality which allows multiple (potentially parallel) executions of the same workflow in a single scheduler is not fully supported by all commands and is yet to be documented.

Browser Based UI

The old “GUI” has been replaced by the new browser-based “UI”.

Graph View

There is no graph view in the Cylc UI as yet. A new graph view will be developed providing both “live” (AKA cylc gui) and “offline” (AKA cylc graph) functionalities.

Log Files

The ability to view job log and other files is yet to be implemented.

Multiple Selection

Multiple selection is yet to be implemented, however, it is possible to issue action for multiple tasks (e.g. kill) without using multiple selection:

  • From the UI click on a workflow/cycle/task/job.

  • Find the action you want to call (e.g. kill).

  • Click the pencil symbol next to this action.

  • Edit the workflows/cycles/tasks/jobs in the form and press submit.


Installing Workflows

At present there is no way to view uninstalled workflows in the UI. We will add the ability to view and install workflows from the UI.

Rose Edit

Rose Edit is awaiting reimplementation in the UI.

Trigger Edit

Functionality removed pending reimplementation.

Xtrigger Visibility

Xtriggers are not yet visible in the UI.

Documentation / Orientation Guide

Some form of documentation will be provided within the UI itself.

Terminal User Interface

The cylc tui command (Tui) replaces the old cylc monitor, it provides a tree view that is very similar to the Cylc UI and supports some control functionality.


TUI currently refreshes its display every second. Large workflows which change rapidly may evolve faster than TUI is able to keep pace with which will cause TUI to freeze.

A more performant implementation which does not rely on a scheduled global update will follow in due course.


The old cylc gscan command has been removed. You can now find the gscan display on the left-hand side of the Cylc UI.

In a future release cylc tui will be able to list workflows in a similar way.

UI Server


Only “binary” authorisation (i.e. no access / full control) is currently supported.


The ability to route Cylc commands via the UIS is planned for a future relase