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Restart Docker container on image change

This blog is a static website served from a Docker container. The content is written in markdown and pushed to a Git repository hosted on GitHub. Every time I push to that repository a Docker image containing the new version is build on DockerHub.

While the new image is available on DockerHub there is still a container running containing the old version. Normally I would go to the server where the container is running and perform a manual docker pull command and spin up a new container. I hated doing this manual step and automated it:

👉 The people from containrrr.dev made a simple to use piece of software called watchtower. This detects when the image of a container changes. When that happens the changed image is pulled and the container will be restarted. Watchtower can be started as an individual Docker container with the following command:

docker run -d \
--name watchtower \
-v /var/run/docker.sock:/var/run/docker.sock \
containrrr/watchtower <name of the container to watch : optional>

📓 if no name is given all containers are watched.

I like to configure and document my containers with a docker-compose file. This is also supported by watchtower.

version: "3"
services:
cavo:
image: jurruh/blog:latest
container_name: jurruh_blog
ports:
- "80:80"
watchtower:
image: containrrr/watchtower
volumes:
- /var/run/docker.sock:/var/run/docker.sock
command: jurruh_blog