Docker cheatsheet

docker-cheatsheet.sh

# Docker - platform for containerization
# version: 17.12.0-ce

# Image - read-only template with instructions for creating a docker container.
# Container - runnable instance of an image.

# After installation need to add user to docker group
sudo usermod -aG docker $(whoami)

################################################################################
# Dockerfile - config defining the steps needed to create the image and run it.
# Each instruction in a Dockerfile creates a layer in the image. When you change
# the Dockerfile and rebuild the image, only those layers which have changed
# are rebuilt.

FROM <parent_image>:<version>  # specify parent layer
RUN <shellstr>  # run command (shell form)
RUN [<cmdarg>...]  # exec form

ARG <name>=<default>  # variable that can be passed at build time
	# using `--build-arg <name>=<value>` and can be used inside
	# Dockerfile as `$name`
ENV <name> <value>  # environment variable

EXPOSE <port>...  # make port available inside container

WORKDIR /<path>       # set cwd
COPY <path> /<path>   # copy files into container

CMD <shellstr>  # default command to run app (shell form)
CMD [<cmdarg>...]  # exec form

################################################################################

docker info  # show details about installed docker, images, containers

docker build -t <name>:<tag> <src_path>  # build new image with version <tag>

docker run <image> [<cmd arg...>]  # run new container
	# <image> can be <usename>/<repository>:<tag> to pull from repo and run
	-p <foreign>:<inner>  # map ports
	--network bridge|host|overlay|macvlan|none  # connect to network
	--name <name>  # specify name for new container
	-d  # detached mode (run in background)
	-i  # interactive
	-t  # allocate pseudo tty
	-a stdin|stdout|stder  # attach to stdin, stdout and/or stderr
	--rm  # automatically remove when exits

	--volume <volume|host_path>:<mount_path>  # attach storage
	--mount <options>  # attach storage (more explicit syntax)
		# options: comma-separated key=value pairs
			type=bind|volume|tmpfs
			source=<host_path>
			destination=<mount_path>
			readonly=true
			bind-propagation=rprivate|private|rslave|slave|rshared|shared
				# whether or not sub-mounts can be propagated to replicas
				# r - recursive

docker ps  # list running containers
docker start <container>  # run stopper container
	-i  # interactive
	-a  # attach stdout and stderr and forward signals
docker attach <container>  # back to foreground
docker exec <container> <cmd arg...>  # execute in running container
docker stop <container>  # gracefully stop running container
docker kill <container>  # force stop

docker image ls  # list images
	-a  # all (default hides intermediate images)
docker image rm <image>  # remove image
docker image prune       # remove all dangling images
	-f  # without prompt

docker container ls  # list containers
	-a  # all (default hides stopped)
docker container rm <container>  # remove container
docker container prune           # remove all stopped containers
	-f

docker volume create <volume>  # create storage
	# volumes stored in /var/lib/docker/volumes/<volume-name>
docker volume ls  # list volumes
docker volume rm <volume>  # remove volume

docker cp <path>/. <container>:/<path>  # copy files from host to container

################################################################################
# Dockerfile example:

FROM debian:stretch

RUN apt-get update -y
RUN apt-get install -y python3
RUN apt-get install -y python3-pip

RUN apt-get install -y \
	apt-transport-https \
	ca-certificates \
	curl \
	gnupg2 \
	software-properties-common
RUN curl -fsSL https://download.docker.com/linux/$(. /etc/os-release; echo "$ID")/gpg | apt-key add -
RUN apt-key fingerprint 0EBFCD88
RUN add-apt-repository \
	"deb [arch=amd64] https://download.docker.com/linux/$(. /etc/os-release; echo "$ID") \
	$(lsb_release -cs) \
	stable"
RUN apt-get update -y
RUN apt-get install -y docker-ce

WORKDIR /app

COPY ./requirements.txt ./
RUN pip3 install -r ./requirements.txt

COPY ./* ./

CMD pytest -sv ./