Posted By: Anonymous
I’m not sure if I’ve misunderstood something here, but it seems like it’s only possible to set port mappings by creating a new container from an image. Is there a way to assign a port mapping to an existing Docker container?
You can change the port mapping by directly editing the
hostconfig.json file at
/var/snap/docker/common/var-lib-docker/containers/[hash_of_the_container]/hostconfig.json, I believe, if You installed Docker as a snap.
You can determine the [hash_of_the_container] via the
docker inspect <container_name> command and the value of the "Id" field is the hash.
- Stop the container (
docker stop <container_name>).
- Stop docker service (per Tacsiazuma’s comment)
- Change the file.
- Restart your docker engine (to flush/clear config caches).
- Start the container (
docker start <container_name>).
So you don’t need to create an image with this approach. You can also change the restart flag here.
P.S. You may visit https://docs.docker.com/engine/admin/ to learn how to correctly restart your docker engine as per your host machine. I used
sudo systemctl restart docker to restart my docker engine that is running on Ubuntu 16.04.