Docker swarm version upgrade without causing downtime

Question

I am using docker swarm (version 1.12.0). Is there any way we can upgrade the swarm version to 1.12.1 without causing downtime?

P.S. I could not find anything on docker swarm documentation neither on the docker swarm 1.12.1 release notes.

Answer 1

Short answer: no. The live restore feature lets you stop the Docker daemon, upgrade and restart without losing any running containers, but it's not compatible with Swarm Mode.

If your containers are stateless, then you can manually upgrade each node by leaving the swarm with docker swarm leave, upgrading and joining again. The swarm will start containers on new nodes while you're upgrading others, so you won't lose service.

If you have volumes mapped in your containers and you can't have them moving around the swarm, I don't think you can do this without loss of service.