kriskbx/ofelia repository overview

⁠Ofelia - a job scheduler

Ofelia is a modern and low footprint job scheduler for docker environments, built on Go. Ofelia aims to be a replacement for the old fashioned cron⁠.

⁠Why?

It has been a long time since cron⁠ was released, actually more than 28 years. The world has changed a lot and especially since the Docker revolution. Vixie's cron works great but it's not extensible and it's hard to debug when something goes wrong.

Many solutions are available: ready to go containerized crons, wrappers for your commands, etc. but in the end simple tasks become complex.

⁠How?

The main feature of Ofelia is the ability to execute commands directly on Docker containers. Using Docker's API Ofelia emulates the behavior of exec⁠, being able to run a command inside of a running container. Also you can run the command in a new container destroying it at the end of the execution.

⁠Configuration

⁠Jobs

Scheduling format⁠ is the same as the Go implementation of cron. E.g. @every 10s or 0 0 1 * * * (every night at 1 AM).

Note: the format starts with seconds, instead of minutes.

you can configure four different kind of jobs:

• job-exec: this job is executed inside of a running container.
• job-run: runs a command inside of a new container, using a specific image.
• job-local: runs the command inside of the host running ofelia.
• job-service-run: runs the command inside a new "run-once" service, for running inside a swarm

See Jobs reference documentation⁠ for all available parameters.

⁠INI-style config

Run with ofelia daemon --config=/path/to/config.ini

[job-exec "job-executed-on-running-container"]
schedule = @hourly
container = my-container
command = touch /tmp/example

[job-run "job-executed-on-new-container"]
schedule = @hourly
image = ubuntu:latest
command = touch /tmp/example

[job-local "job-executed-on-current-host"]
schedule = @hourly
command = touch /tmp/example


[job-service-run "service-executed-on-new-container"]
schedule = 0,20,40 * * * *
image = ubuntu
network = swarm_network
command =  touch /tmp/example

⁠Docker labels configurations

In order to use this type of configurations, ofelia need access to docker socket.

docker run -it --rm \
    -v /var/run/docker.sock:/var/run/docker.sock:ro \
    --label ofelia.job-local.my-test-job.schedule="@every 5s" \
    --label ofelia.job-local.my-test-job.command="date" \
        mcuadros/ofelia:latest daemon --docker

Labels format: `ofelia.<JOB_TYPE>.<JOB_NAME>.<JOB_PARAMETER>=<PARAMETER_VALUE>. This type of configuration supports all the capabilities provided by INI files.

Also, it is possible to configure job-exec by setting labels configurations on the target container. To do that, additional label ofelia.enabled=true need to be present on the target container.

For example, we want ofelia to execute uname -a command in the existing container called my_nginx. To do that, we need to we need to start my_nginx container with next configurations:

docker run -it --rm \
    --label ofelia.enabled=true \
    --label ofelia.job-exec.test-exec-job.schedule="@every 5s" \
    --label ofelia.job-exec.test-exec-job.command="uname -a" \
        nginx

Now if we start ofelia container with the command provided above, it will pickup 2 jobs:

• Local - date
• Exec - uname -a

Or with docker-compose:

version: "3"
services:
  ofelia:
    image: mcuadros/ofelia:latest
    depends_on:
      - nginx
    command: daemon --docker
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock:ro
    labels:
      ofelia.job-local.my-test-job.schedule: "@every 5s"
      ofelia.job-local.my-test-job.command: "date"

  nginx:
    image: nginx
    labels:
      ofelia.enabled: "true"
      ofelia.job-exec.datecron.schedule: "@every 5s"
      ofelia.job-exec.datecron.command: "uname -a"

⁠Logging

Ofelia comes with three different logging drivers that can be configured in the [global] section:

• mail to send mails
• save to save structured execution reports to a directory
• slack to send messages via a slack webhook

⁠Options

• smtp-host - address of the SMTP server.

• smtp-port - port number of the SMTP server.

• smtp-user - user name used to connect to the SMTP server.

• smtp-password - password used to connect to the SMTP server.

• email-to - mail address of the receiver of the mail.

• email-from - mail address of the sender of the mail.

• mail-only-on-error - only send a mail if the execution was not successful.

• save-folder - directory in which the reports shall be written.

• save-only-on-error - only save a report if the execution was not successful.

• slack-webhook - URL of the slack webhook.

• slack-only-on-error - only send a slack message if the execution was not successful.

⁠Overlap

Ofelia can prevent that a job is run twice in parallel (e.g. if the first execution didn't complete before a second execution was scheduled. If a job has the option no-overlap set, it will not be run concurrently.

⁠Installation

The easiest way to deploy ofelia is using Docker. See examples above.

If don't want to run ofelia using our Docker image you can download a binary from releases⁠ page.