Developing on Staxmanade

How to Update a Single Running docker-compose Container

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As a newbie to the tooling, docker-compose it's great for getting started. To bring up all the service containers with a simple docker-compose up starts everything. However, what if you want to replace an existing container without tearing down the entire suite of containers?

For example: I have a docker-compose project that has the following containers.

  1. Node JS App
  2. CouchDB
  3. Redis Cache

I had a small configuration change within the CouchDB container that I wanted to update and re-start to get going but wasn't sure how to do that.

Here's how I did it with little down time.

I'm hoping there are better ways to go about this (I'm still learning), but the following steps are what I used to replace a running docker container with the latest build.

  1. Make the necessary change to the container (in my case update the couchdb config).
  2. Run docker-compose build couchdb (docker-compose build <service_name> where service_name is the name of the docker container defined in you're docker-compose.yml file.)

Once the change has been made and container re-built, we need to get that new container running (without affecting the other containers that were started by docker-compose).

  1. docker-compose stop <service_name> <-- If you want to live on the edge and have the shut-down go faster, try docker-compose kill <service_name>
  2. docker-compose up -d --no-deps <service_name> <-- this brings up the service using the newly built container.

The -d is Detached mode: Run containers in the background, print new container names.

The --no-deps will not start linked services.

That's it... at least for me, it's worked to update my running containers with the latest version without tearing down the entire docker-compose set of services.

Again, if you know of a faster/better way to go about this, I'd love to hear it. Or if you know of any down-sides to this approach, I'd love to hear about it before I have to learn the hard way on a production environment.

UPDATE:

Thanks to Vladimir in the comments below - you can skip several steps above and do it with a single command

docker-compose up -d --no-deps --build <service_name>

I tested this and was able to avoid the build, kill, and up commands with this one-liner.

Happy Container Updating!

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