Swarm Mode

Doco-CD also supports Docker Swarm mode, which allows you to manage a cluster of Docker engines as a single virtual engine. This is useful for deploying applications across multiple nodes and ensuring high availability.

If the Docker daemon is running in Swarm mode, doco-cd will detect this automatically and deploy everything as Swarm stacks instead of simple Compose projects.

You can overwrite this to always deploy as Compose projects while running doco-cd in a Swarm environment by setting the DOCKER_SWARM_FEATURES environment variable to false (See the Docker Settings).

The deployment happens the same way as with Docker Compose projects, see the Deploy Settings

Configs and Secrets¶

When deploying configs or secrets in Swarm mode, doco-cd will add a suffix to the name of configs and secrets. This suffix is a shortened sha256 hash of the config or secret content, which allows doco-cd to rotate them if their contents change. After rotating, doco-cd will also clean up old versions of the configs or secrets to prevent clutter.

For example, if you deploy a stack named myapp with a config named db-settings and the content of the config is hello world, doco-cd will create a config named myapp_db-settings_a948904f in the Swarm cluster.

If you later change the content of the config to hello universe, doco-cd will create a new config named myapp_db-settings_0b5c6934, redeploy the service/container with the new config and remove the old config myapp_db-settings_a948904f from the Swarm cluster.