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Starting, stopping and deleting contains #

Last updated February 2021

Most common commands I use to manage Docker containers.

Starting a new Docker container

-d

Run in detached mode with no CLI that continues running when terminal closes.

--restart unless-stopped

Restart the container if Docker closes unless container has been manually stopped.

• no - do not automatically restart the container (the default)
• on-failure - restart the container if it exits due to an error, which manifests as a non-zero exit code
• always - always restart the container if it stops. If it is manually stopped, it is restarted only when Docker daemon restarts or the container itself is manually restarted
• unless-stopped - (my most used) similar to always, except that when the container is stopped (manually or otherwise), it is not restarted even after Docker daemon restarts

-v $PWD/x:/y

Map a local file/directory to one within container. Both directories must be absolute hence why $PWD is present and non-optional.

-p HOST_PORT:CONTAINER_PORT(/tcp|udp)

Map a container port to the host. Specifying TCP/UDP is optional and is TCP by default.

username/imgname

The local or external Docker image.

List running containers

docker ps

List all containers

docker ps -a

List only IDs (for scripts)

docker ps -q

Stop a Docker Container

Docker will call SIGTERM and then after a grace period, SIGKILL

docker stop [container id]

Delete Single Container

docker rm [container id]

Delete all Containers

docker rm `docker ps -aq`

Docker based development #

Last updated February 2021

I believe this to be an insane idea and should not be tried, though I keep it here for prosperity. 2026/01/29

Method of spinning up a Docker container for each project instead of installing the toolchain on the host computer.

Why not a Dockerfile

Dockerfiles are the preferred method for deploying apps, their only limitation is that they produce a static image which isn't ideal for rapid development.

This method takes the best of both worlds when deploying with Docker or developing on your local machine: a clean environment with an already configured toolchain and a live shell for development.

Don't be mistaken: this method isn't for deployment, only for development.

Method Outline

1. Start a new Docker container with a toolchain-specific image while binding the directory and ports
2. Run a new shell within the container from your terminal
3. Additional setup, e.g. installing package or external dependencies
4. Running the command(s) to start the app

Starting a new container with a shell

In this example a Jekyll app is used. Ruby's toolchain is generally annoying to configure but using Docker containers can make it easier:

-it

Keep the container interactive so we can use a shell. In Docker's words:

• -i, Keep STDIN open even if not attached
• -t, Allocate a pseudo-TTY

--name moodboard

The name of the Docker container.

-p 3000:80

Bind the container's port 80, to the host's port 3000.

-v "$PWD/moodboard":/usr/app

Bind a host's directory to the container's `/usr/app` directory. The container's directory is fully optional, this is where you will `cd` to run your app.

ruby

Run the `ruby:latest` image.

bash

Run a bash shell inside of the container.

Re-attaching to a container

After exiting out of the container for the first time it'll auto shutdown. Start it back up and re-attach bash:

1. Start it up

   docker start [name]

2. Run an interactive shell

   docker exec -it [name] bash

3. Optionally stop it when finished

   docker stop [moodboard]

Non-interactive

In some cases you don't need an interactive shell. Apache is a great example of this, by binding a directory and port you can quickly spin up a local webserver.

The command structure looks similar but without a shell or interactive-based flags. Also check the image's docs to find out which directory the image requires.