Docker swarm update through Continuous Deployment

Question

I need a clarification about the correct process to use a CD to update an environment where a Docker Swarm runs. I understood that I can configure my CD to execute docker service update --image foo:1.1.0 fooservice inside the Swarm and so having my stack always up to last image. But I do not understand how to manage my stack.yml files: I initialize the swarm copying on the machine my stack files which defines the "state of the art" of my services; but when the CD updates the running images, the files become outdated.

Should I replace the service update command with something that modifies the stack files and redeploy? Or is it expected that yml files become obsolete?

Answer 1

I have built pipeline for kubernetes but not for docker swarm, but it seems like the principles are the same.

The pipelines normally follow this structure in azure devops:

-Build(docker push+publish yml files as artifacts)
 -Release dev(download artifacts)
 -Release uat(download artifacts)
 -Release prod(download artifacts)

Here in each release step you would transform image tag to match the build version. e.g. foo:#{BUILD_NO}# where #{BUILD_NO}# is replaced using an appropiate task for this purpose assuming we tag the docker image with the build no.

• Marco Stramezzi: Thanks for your reply! What do you mean when you say "publish yml as artifacts"?
• Esben Skov Pedersen: It may be too azure devops specific, but it is the way to transfer files from build stages to release stages.