Swarm Updater

Automatically update Docker services whenever their image is updated. Inspired on v2tec/watchtower

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.
• --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.

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.

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.