Updating containers

Software needs to be updated in a regular basis. Containers are no different in this regard. Depending on how you are managing containers this can be tedious or simple.

docker-compose

If you are using docker compose this quite easy.

1. Check for new images and download them:

    docker-compose pull

2. Re-create containers with the updated images:

    docker-compose up -d

If you just want to check without pulling:

docker-compose images

or

docker compose pull --dry-run

podman

1. Check for updates

   podman image check --all

   or

   podman image check <image name>

2. Pull images (if updated)

   podman pull --policy=always <image name>

Podman can do automatic updates:

1. Create your container with:

   --label "io.containers.autoupdate=image"

2. Then you can run:

    podman auto-update

Docker

Docker doesn't have automatic updates. You can use What's UP Docker or Watchtower to do this.

Manually the process looks like this:

docker pull myimage:latest
docker stop mycontainer
docker rm mycontainer
docker run -d --name mycontainer myimage:latest

Pinning versions

I personally dislike using latest tag and pin a specific version tag. I use this script to check for version changes. Example usage:

sh container_check.sh -e '^\d+\.\d+\.\d+$' jellyfin/jellyfin:10.11.6
sh container_check.sh -e '^\d+\.\d+\.\d+$' nginx:1,25.3  -e '^v\d+' ghcr.io/tortugalabs/mylldap:v0.6.2-2026.02

This will show matching tags that are newer than your current tag.

Then you can use runlike (a python PIP package) to re-create the docker run command.

Podman is easier in that regard. You can get the run command with:

podman inspect <image name> | jq .[0].Config.CreateCommand

Alternatively, run the container via a YAML file:

1. Generate a K8s YAML file:

   podman generate kube <container> > container.yaml
   

2. modify the YAML file, maybe update the image name.
3. Remove the container.

4. Re-create container:

   podman play kube container.yaml