Stopping All Running Containers

To halt all running containers simultaneously, use the following command:

docker stop $(docker ps -q)

This command provides a quick solution for developers who frequently work with multiple containers, eliminating the need to stop each one individually.

Official Docker stop documentation.

Naming and Auto-Removing Containers During Testing

When building new containers, you often create numerous test builds. To simplify this process, you can use the --rm flag to automatically remove a container once it exits. Here’s how you can do it:

docker run -d --rm --name testing debian:latest sleep 300

By naming your containers with the --name parameter, you can easily identify them later for removal or reuse. In this example, a Debian container called "testing" is created, which will run for 300 seconds before being removed.

Official Docker run documentation.

Assessing Current Docker Disk Usage

To check the disk space consumed by Docker resources, use the following command:

docker system df

This command provides a summary of disk usage across images, containers, volumes, and build cache. The output will display the total and active space used, as well as reclaimable space.

For a detailed view of resource consumption, the -v flag can be added for verbose output.

Official Docker system documentation.

Pruning Unused Images

Over time, you may accumulate many unused images that consume significant disk space. To remove these images, use:

docker image prune -a

This command eliminates all images that are not currently associated with a container, helping you recover valuable disk space. Be cautious with the docker system prune command, as it is more aggressive and removes stopped containers too. Use it only when you are certain you don't need those resources.

Official Docker image prune documentation.

Monitoring Container Resource Usage

If your containers are running resource-intensive tasks, it’s essential to monitor their usage. Use the following command to check resource statistics:

docker stats --no-stream

This command provides a snapshot of resource usage for all running containers, allowing you to identify any that may be overusing CPU or memory. If necessary, you can stop or kill a problematic container.

Official Docker stats documentation.