Docker.github.io: How do you map a port on running container?

[Mararesliu]

On runnning container, want to export a port outside, Any ways can quick reach it ?
docker commit and new a container is not a good idea in my stuation.
iptables seems can not take effect.

[Mararesliu]

thanks, any progress?

[mdlinville]

You can't change a port mapping on a running container, but you can stop the container and restart using the -p host:container flag or by using the correct directive in the Docker compose file. See https://docs.docker.com/compose/compose-file/#ports.

[Mararesliu]

@mstanleyjones
docker stop container_id
docker start -p host:container container_id ?
It's not a legitimate command...

[mdlinville]

You're right, you'd run the docker run again:

docker run -d -p 4000:4000 --name mytest mistytest

docker container stop mytest

docker container start mytest # same port

docker container stop mytest

docker container run -p 4001:4000 mytest # Now mapping container port 4000 to host port 4001

[Mararesliu]

@mstanleyjones
It can not run success, see follow
docker container run -p 3306:3306 some-mysql
Unable to find image 'some-mysql:latest' locally
docker: Error response from daemon: Get https://registry-1.docker.io/v2/library/some-mysql/manifests/latest: unauthorized: incorrect username or password.
See 'docker run --help'.

[bhavin192]

You need to specify image name correctly which is mysql not some-mysql
So the command should be

docker run -p 3306:3306 --name name_for_container mysql

name_of_container is just a name which you can give to the container so that it would be easy to run commands related to container like docker exec

[Mararesliu]

Thanks, but we talk about remaping port for a container, the "some-mysql" is that container which want to remaping port. docker run -p would create a new container not modify the old one.
If can not be modified, all of the containers's relationship will be disabled, and I must to recreate some of them.
@bhavin192 @mstanleyjones

[mdlinville]

I will try to be more clear.

1. docker stop <running-container-name>
2. docker run -p <new-port-mapping> <container-name-from-step-1>

[sadjunky]

Tried and tested.

• Stop your container using docker stop <container-name/container-id>.

• Edit hostconfig.json and config.v2.json files of the respective container by adding your port to PortBindings key and ExposedPorts key respectively.

• You'll require sudo access, or as root user. Then run systemctl stop docker and then run systemctl start docker.

• Finally start your container using docker start <container-name/container-id>.

[sadjunky]

@JonathanAlumbaugh Make a search on your machine for hostconfig.json. You should find a file
in /var/lib/docker/containers/<container-id>.

[wanglailai]

@sadjunky In my case, systemctl stop docker should be executed before edit hostconfig.json and
config.v2.json; or the config files will be restored.

[sadjunky]

@sadjunky In my case, systemctl stop docker should be executed before edit hostconfig.json and
config.v2.json; or the config files will be restored.

Haven't checked, will try this out. Thanks for the heads up!

[browncrane]

@sadjunky In my case, systemctl stop docker should be executed before edit hostconfig.json and
config.v2.json; or the config files will be restored.

I edit the hostconfig.json before systemctl stop docker and it worked.
It's Ubuntu 18.04 x86_64 with

docker --version
Docker version 18.09.5, build e8ff056

[Eyshika]

Tried and tested.

• Stop your container using docker stop <container-name/container-id>.
• Edit hostconfig.json and config.v2.json files of the respective container by adding your port to PortBindings key and ExposedPorts key respectively.
• You'll require sudo access, or as root user. Then run systemctl stop docker and then run systemctl start docker.
• Finally start your container using docker start <container-name/container-id>.

i guess its not ExposedPort inside config.v2.json rather its Ports.

Also when i did sudo service docker stop it removed my docker :/

[bharatrbk]

how can I stop port of a docker, running container.

[geeksun]

Use dockerFile can solve this problem. More pls see the link:　https://bobcares.com/blog/docker-change-container-configuration/

[hjonin]

@Eyshika
Also when i did sudo service docker stop it removed my docker :/

The same happened to me because I made a mistake (typo) in the configuration, and when I fixed it the container reappeared (after restarting docker). It should probably be the same for you.

[HamaniKhalil]

@JonathanAlumbaugh Make a search on your machine for hostconfig.json. You should find a file
in /var/lib/docker/containers/<container-id>.

Can you give the location for Mac OSX please ? Thanks

[alexleekt]

@HamaniKhalil
docker run -v /var/lib/docker:/var/lib/docker ubuntu bash
then /var/lib/docker/containers/<container-id> in the bash container that starts.

ref: https://github.com/moby/moby/issues/28283

[matfolio]

An alternative to the above option of exposing port on a running container from the host machine is to create an image from the container. Then run the newly created image with desired ports to create a container with the port bindings

docker commit -m "msg" ``docker -l -q`` <your-container:version_number>
The above code would create a new image tagged with the [version_number]
then:
docker run -it --name <container_name> --hostname <container_name> <new_image>
The above command would create a container using the created image.
well the hostname option is not needed if your're running in detatched or daemon mode.

Note: Editing the container config files and stopping the docker for such modification might results into unwanted issues. I prefer this option rather than editing the config files.