docker-batch-scheduler

WIP for a docker batch scheduler

Usage

$APPNAME requires access to the Docker, so it may need to be run as root, or, if in a Docker container, need the socket mapped as a volume.

Running $APPNAME

As simple as:

./$APPNAME

It will then run in the foreground, periodically checking Docker for containers with labels containing a cron schedule.

$APPNAME will periodically poll Docker for new containers or schedule changes.

Scheduling a container

First, be sure your container is something that is not long running and will actually exit when complete. This is for batch runs and not keeping a service running. Docker should be able to do that on it's own with a restart policy.

Create your container and add a label in the form $APPNAME.cron.schedule="* * * * *", where the value is a valid cron expression (See the section Cron Expression Formatting).

$APPNAME will now start that container peridically on the schedule.

Cron Expression Formatting

For more information on the cron expression parsing, see the docs for robfig/cron.

Caveats

$APPNAME is quite simple right now. It does not yet:

• Issue any retries
• Cancel hanging jobs

I intend to keep it simple as well. It will likely never:

• Provide any kind of alerting (check out Minitor)
• Handle job dependencies

Either use a separate tool in conjunction with $APPNAME, or use a more robust scheduler like Tron, or Chronos.