Docker

Docker is a platform for developing, shipping, and running applications in containers. Containers allow a developer to package up an application with all parts it needs, such as libraries and other dependencies, and ship it all out as one package. By doing so, the developer can be sure that the application will run on any other Linux machine regardless of any customized settings that machine might have that could differ from the machine used for writing and testing the code.

Docker commands¶

Create an image from a Dockerfile¶

docker build -t {imageName} -f {path}

Run a container¶

It is used to create and start a container. It is like docker create {imageId} + docker start -a {containerId}.

-a is used to attach the standard input, output, and error streams to the terminal.

docker run {imageId}

Executing commands in a running container¶

docker exec -it {containerId} {command}

-i is used to keep the standard input open i.e. stdin.
-t is used to allocate a pseudo-tty to container's stdout and stderr.
{command} is the command to be executed in the container.

List all containers¶

docker ps --all

List all images¶

docker images

Restart a running container¶

docker restart {containerId}

Start a stopped container¶

docker start {containerId}

Stop a container¶

docker stop {containerId} #SIGTERM

docker kill {containerId} #SIGKILL

kill sends a SIGKILL signal to the container, which immediately terminates the container. stop sends a SIGTERM signal to the container, which allows the container to exit gracefully by waiting for about 10 seconds and if it still does not stop then it sends a SIGKILL signal.

Remove a container¶

docker rm {containerId}

Remove all stopped containers¶

docker system prune

Remove an image¶

docker rmi {imageId}

Remove all containers¶

docker container rm $(docker ps -a -q)

Remove all images¶

docker image rmi $(docker images -q)

Retrieve logs from a container¶

docker logs {containerId}