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2020-06-14 Docker

Docker Commands Quick Start

Docker Quickstart#

Build a dockerfile:

docker build -t <name> .

List the available images:

docker images

Run an image:

docker run <image_name>:<tag>

If you want to run it in the background use -d

docker run elastalert:latest -d

If you want to publish a containers ports to the host use -p:

docker run <image>:<version> -d -p <port on host>:<port on container> -p <port on host>:<port on container> --net="host"

Eg.

docker run elastalert:latest -d -p 3030:3030 -p 3333:3333 --net="host"

If you want to bind a volume use -v:

docker run elastalert:latest -d -p 3030:3030 -v $HOME/myContainer/configDir:/myImage/configDir

Use --name to assign a name to the container

More info on the docker run reference

View all running and non-running containers:

docker ps -a

Remove an image:

docker rm <name>

Get the reason why a docker container exited:

docker logs <container-id>

Inspect the container:

docker inspect <container-id>

Ensure a container is removed when it exits or stops, use --rm:

docker run --rm -d --network host --name my_nginx nginx

Key Concepts#

You got Images and Containers, and you need to know what state you are at:

  • Does the docker image exist?
  • Does the docker container exist?
  • Is the docker container running?

If we are talking containers your command will look like:

docker container <command>

These are container commands:

  • create — Create a container from an image.
  • start — Start an existing container.
  • run — Create a new container and start it.
  • ls — List running containers.
  • inspect — See lots of info about a container.
  • logs — Print logs.
  • stop — Gracefully stop running container.
  • kill —Stop main process in container abruptly.
  • rm— Delete a stopped container.

If we are dealing with images:

docker image <command>

These are image commands:

  • build — Build an image.
  • push — Push an image to a remote registry.
  • ls — List images.
  • history — See intermediate image info.
  • inspect — See lots of info about an image, including the layers.
  • rm — Delete an image.

Misc commands:

  • docker version — List info about your Docker Client and Server versions.
  • docker login — Log in to a Docker registry.
  • docker system prune — Delete all unused containers, unused networks, and dangling images.

Container#

Create a container from an image

docker container create my_repo/my_image:my_tag

You can use -a for attach (for STDIN, STDOUT or STDERR)

docker container create -a STDIN my_image

Start an existing container

docker container start my_container

A container can be refered to by its id or name

Run combines both create and start:

docker container run my_image

Some options:

  • -i or --interactive - Keep STDIN open even if unattached
  • -t or --tty - Allocates a pseudo terminal that connects your terminal with the container’s STDIN and STDOUT
  • -p or --port - The port is the interface with the outside world. 1000:8000 maps the docker port 8000 to port 1000 on your machine / host. Eg. go to localhost:1000 on your host
  • --rm - automatically remove container when it stops running
  • -d or --detach - Run the container in the background as a daemon

List all containers and sizes:

docker container ls -a -s

Inspect a container:

docker container inspect my_container

Print a containers log:

docker container logs my_container

Stop a running container:

docker container stop my_container

Stop a running container immediately (abruptly):

docker container kill my_container

Kill all running containers:

docker container kill $(docker ps -q)

Delete one or more containers:

docker container rm my_container

Image#

Build a docker image from a dockerfile located at a specific path:

docker image build -t my_repo/my_image:my_tag .

Pushing an image to a registry

docker image push my_repo/my_image:my_tag

List images and sizes

docker image ls

View the history of an image:

docker image history my_image

Show details and layers of your image:

docker image inspect my_image

Remove an image

docker image rm my_image

Admin#

Get docker system info

docker system info

Delete unused containers, unused networks and dangling images

docker system prune

Show docker disk usage

docker system df