Docker

Docker

Docker-cheat-sheet.pdf

Containers

List running containers

docker ps

List all containers

docker ps -a

Run a container

docker run [image] [command]
-d detached
-i interactive
-t terminal  (usually -it)
-e VAR=value  (environment variables)
-v VOLUME_NAME:/container/mount/point
--entrypoint=sleep [image] [attribute]
--name name
--network network_name
--link real_container_name:target_name  (adds entries to /etc/hosts)

run:version (using a tag)

Port mapping

-p (host/external):(container/internal)

Directory mapping

-v /host/dir:/container/dir

Inspect (returns json)

docker inspect [container]

Images

List images

docker image ls

Remove image (must have no containers attached)

docker rmi [image]

Dockerfile

Contains Instructions or Arguments

CMD can be as per cli or in json format

CMD command param1
CMD ["command","param1"]

FROM ubuntu:18.04
COPY . /app
ADD root/bashrc /root/.bashrc
ENV HOME /root
WORKDIR /root
RUN make /app
CMD python /app/app.py

Build

docker build [path/Dockerfilefolder]
-t name:tag

Create a Ubuntu container that sleeps for 5 seconds before exiting Dockerfile

From Ubuntu
CMD sleep 5

docker build -t ubuntu-sleeper .
docker run ubuntu-sleeper

Dockerfile

From Ubuntu
ENTRYPOINT ["sleep"]
CMD ["5"]             (becomes the default)

docker build -t ubuntu-sleeper .
docker run ubuntu-sleeper 10

Networks

docker network ls

Containers can resolve containers by name in the same network (internal dns server 127.0.0.11)

Create a network

docker network create --driver bridge --subnet 182.18.0.0/16 custom-isolated-network

Bridge

Internal network common to all docker containers in 172.17.0.0/24 network

None

Containers are isolated. Containers are not connected to any network

Host=

Container runs directly on the host network.

Storage

Default storage

/var/lib/docker

Create volume

docker volume create data_volume  (generated /var/lib/docker/volumes/data_volume

Use Volume

docker run --mount data_volume:/var/lib/mysql mysql

Bind Mounting (with new syntax)

 docker run --mount type=bind,source=/host/data/mysql,target=/var/lib/mysql mysql

Compose

Yaml - run multiple containers together on a single Docker Host.

docker compose up