Swarm Updater

Automatically update Docker services whenever their image is updated. Inspired on containrrr/watchtower

Delay swarm-updater to be the last updated service

You must add the xyz.megpoid.swarm-updater=true label to your service so the updater can delay the update of itself as the last one.

    deploy:
      labels:
        - xyz.megpoid.swarm-updater=true
      placement:
        constraints:
          - node.role == manager

Update services on demand

The endpoint /apis/swarm/v1/update can be called with a list of images that should be updated on matching services on the swarm.

{
  "images": [
    "mycompany/myapp"
  ]
}

Options

Every command-line option has their corresponding environment variable to configure the updater.

• --host, -H Docker daemon socket to connect to. Defaults to "unix:///var/run/docker.sock" but can be pointed at a remote Docker host by specifying a TCP endpoint as "tcp://hostname:port". The host value can also be provided by setting the DOCKER_HOST environment variable.
• --config, -c Docker client configuration path. In this directory goes a config.json file with the credentials of the private registries. Defaults to ~/.docker.The path value can also be provided by setting the DOCKER_CONFIG environment variable.
• --schedule, -s Cron expression in 6 fields (rather than the traditional 5) which defines when and how often to check for new images. An example: --schedule "0 0 4 * * *" . The schedule can also be provided by setting the SCHEDULE environment variable. Defaults to 1 hour. Use none to run the process one time and exit afterward.
• --label-enable, -l Watch services where the xyz.megpoid.swarm-updater.enable label is set to true. The flag can also be provided by setting the LABEL_ENABLE environment variable to 1.
• --blacklist, -b Service that is excluded from updates. Can be defined multiple times and can be a regular expression. Either --label-enable or --blacklist can be defined, but not both. The comma separated list can also be provided by setting the BLACKLIST environment variable.
• --tlsverify, -t Use TLS when connecting to the Docker socket and verify the server's certificate. The flag can also be provided by setting the DOCKER_TLS_VERIFY environment variable to 1.
• --debug, -d Enables debug logging. Can also be enabled by setting the DEBUG=1 environment variable.
• --listen, -a Address to listen for upcoming swarm update requests. Can also be enabled by setting the LISTEN environment variable.
• --apikey, -k Key to protect the update endpoint. Can also be enabled by setting the APIKEY environment variable.
• --max-threads, m Max number of services that should be updating at once (default: 2)
• --help, -h Show documentation about the supported flags.

Other environment variables

• DOCKER_API_VERSIONto set the version of the API to reach, leave empty to use the minimum required for the app.
• DOCKER_CERT_PATH is the directory to load the certificates from. Used when --host is a TCP endpoint.

Private registry auth

A file must be placed on ~/.docker/config.json with the registry credentials (can be overriden with --config or DOCKER_CONFIG). The file can be created by using docker login <registry> and saving the credentials.

Only update the image but don't run the container

You must add the xyz.megpoid.swarm-updater.update-only=true label to your service so only the image will be updated ( useful for cron tasks where the container isn't running most of the time). Note: the service will be reconfigured with replicas: 0 so this does nothing with global replication.