Docker Commands

This section includes some basic Docker commands.

docker run

docker run is used to create and start a new container from an image.

docker run --name test -it debian bash

• run --name test: runs a container named test using the debian:latest image
• -it: allocates a pseudo-TTY connected to the container’s stdin
• bash: starts a bash shell inside the container

docker ps

docker ps is used to list all running containers.

docker ps
docker ps -a # list all containers

docker stop

docker stop is used to stop a running container.

docker stop <container_id>

docker images

docker images is used to list all available images.

docker images

docker pull

docker pull is used to download an image from a registry.

docker pull <image>
# Example
docker pull nginx

docker push

docker push is used to upload an image to a registry.

docker push <username>/<myimage>

The command above pushes an image named <myimage> to the Docker Hub registry under the username <username>.

docker build

docker build is used to build an image from a Dockerfile.

# build an image named <myimage> from the Dockerfile in the current directory
docker build -t <myimage> .

docker rm

docker rm is used to remove one or more containers.

docker rm <container_id>

docker rmi

docker rmi is used to delete one or more images.

docker rmi <image_id>

docker update

docker update is used to update the configuration of one or more containers.

# Example: update CPU and memory limits
docker update --cpus 2 --memory 1g <container_id>

The command below updates the --restart settings of a container.

# disable restart
docker update --restart no <container_id>
# disable restart for all running containers
docker update --restart no $(docker ps -q)

--restart options:

Flag	Description
no	Do not automatically restart the container (default).
on-failure[:max-retries]	Restart the container if it exits due to an error, which manifests as a non-zero exit code. Optionally, limit the number of times the Docker daemon attempts to restart the container using the :max-retries option.
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	Similar to always, except that when the container is stopped (manually or otherwise), it is not restarted even after Docker daemon restarts.