Docker cheat sheet linux academy

Complete Docker CLI

Container Management CLIs

Inspecting The Container

Interacting with Container

Image Management Commands

Image Transfer Commands

Builder Main Commands

The Docker CLI

Manage images

docker build

docker build [options] .
  -t "app/container_name"    # name

Create an image from a Dockerfile.

docker run

docker run [options] IMAGE
  # see `docker create` for options

Run a command in an image.

Manage containers

docker create

docker create [options] IMAGE
  -a, --attach               # attach stdout/err
  -i, --interactive          # attach stdin (interactive)
  -t, --tty                  # pseudo-tty
      --name NAME            # name your image
  -p, --publish 5000:5000    # port map
      --expose 5432          # expose a port to linked containers
  -P, --publish-all          # publish all ports
      --link container:alias # linking
  -v, --volume `pwd`:/app    # mount (absolute paths needed)
  -e, --env NAME=hello       # env vars

Example

$ docker create --name app_redis_1 \
  --expose 6379 \
  redis:3.0.2

Create a container from an image.

docker exec

docker exec [options] CONTAINER COMMAND
  -d, --detach        # run in background
  -i, --interactive   # stdin
  -t, --tty           # interactive

Example

$ docker exec app_web_1 tail logs/development.log
$ docker exec -t -i app_web_1 rails c

Run commands in a container.

docker start

docker start [options] CONTAINER
  -a, --attach        # attach stdout/err
  -i, --interactive   # attach stdin

docker stop [options] CONTAINER

Start/stop a container.

docker ps

$ docker ps
$ docker ps -a
$ docker kill $ID

Manage containers using ps/kill.

Images

docker images

$ docker images
  REPOSITORY   TAG        ID
  ubuntu       12.10      b750fe78269d
  me/myapp     latest     7b2431a8d968

$ docker images -a   # also show intermediate

Manages images.

docker rmi

Deletes images.

Also see

• Getting Started (docker.io)

Dockerfile

Inheritance

Variables

ENV APP_HOME /myapp
RUN mkdir $APP_HOME

Initialization

VOLUME ["/data"]
# Specification for mount point

ADD file.xyz /file.xyz
COPY --chown=user:group host_file.xyz /path/container_file.xyz

Onbuild

ONBUILD RUN bundle install
# when used with another file

Commands

EXPOSE 5900
CMD    ["bundle", "exec", "rails", "server"]

Entrypoint

ENTRYPOINT ["executable", "param1", "param2"]
ENTRYPOINT command param1 param2

Configures a container that will run as an executable.

This will use shell processing to substitute shell variables, and will ignore any CMD or docker run command line arguments.

Metadata

LABEL "com.example.vendor"="ACME Incorporated"
LABEL com.example.label-with-value="foo"

LABEL description="This text illustrates \
that label-values can span multiple lines."

See also

• https://docs.docker.com/engine/reference/builder/

docker-compose

Basic example

# docker-compose.yml
version: '2'

services:
  web:
    build: .
    # build from Dockerfile
    context: ./Path
    dockerfile: Dockerfile
    ports:
     - "5000:5000"
    volumes:
     - .:/code
  redis:
    image: redis

Commands

docker-compose start
docker-compose stop

docker-compose pause
docker-compose unpause

docker-compose ps
docker-compose up
docker-compose down

Reference

Building

web:
  # build from Dockerfile
  build: .

  # build from custom Dockerfile
  build:
    context: ./dir
    dockerfile: Dockerfile.dev

  # build from image
  image: ubuntu
  image: ubuntu:14.04
  image: tutum/influxdb
  image: example-registry:4000/postgresql
  image: a4bc65fd

Ports

  ports:
    - "3000"
    - "8000:80"  # guest:host

  # expose ports to linked services (not to host)
  expose: ["3000"]

Commands

  # command to execute
  command: bundle exec thin -p 3000
  command: [bundle, exec, thin, -p, 3000]

  # override the entrypoint
  entrypoint: /app/start.sh
  entrypoint: [php, -d, vendor/bin/phpunit]

Environment variables

  # environment vars
  environment:
    RACK_ENV: development
  environment:
    - RACK_ENV=development

  # environment vars from file
  env_file: .env
  env_file: [.env, .development.env]

Dependencies

  # makes the `db` service available as the hostname `database`
  # (implies depends_on)
  links:
    - db:database
    - redis

  # make sure `db` is alive before starting
  depends_on:
    - db

Other options

  # make this service extend another
  extends:
    file: common.yml  # optional
    service: webapp

  volumes:
    - /var/lib/mysql
    - ./_data:/var/lib/mysql

Advanced features

Labels

services:
  web:
    labels:
      com.example.description: "Accounting web app"

DNS servers

services:
  web:
    dns: 8.8.8.8
    dns:
      - 8.8.8.8
      - 8.8.4.4

Devices

services:
  web:
    devices:
    - "/dev/ttyUSB0:/dev/ttyUSB0"

External links

services:
  web:
    external_links:
      - redis_1
      - project_db_1:mysql

Hosts

services:
  web:
    extra_hosts:
      - "somehost:192.168.1.100"

sevices

To view list of all the services runnning in swarm

To see all running services

docker stack services stack_name

to see all services logs

docker service logs stack_name service_name 

To scale services quickly across qualified node

docker service scale stack_name_service_name=replicas

clean up

To clean or prune unused (dangling) images

To remove all images which are not in use containers , add - a

To prune your entire system

To leave swarm

To remove swarm ( deletes all volume data and database info)

docker stack rm stack_name  

To kill all running containers

docker kill $(docekr ps -q ) 

Contributor -

Sangam biradar - Docker Community Leader

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