Docker

https://docs.docker.com/reference/cli/docker/ Docker ist ein Tool mit dem man Anwendungen in Containern laufen lassen kann.

Commands

Getting Started

Start a basic Container:

docker pull <imageName>
docker run -it --rm --name <ContainerName> <imageName> <TerminalEntrypoint>

-it: Interactive Terminal --rm: Beim stoppen wird der Container gelöscht --name: Name des laufendes Containers <TerminalEntrypoint>: z.B. /bin/bash

Information

Command	Description
docker ps	List running containers
docker ps -a	List all containers
docker ps -s	List running containers (with CPU / memory)
docker images	List all images
docker inspect <container>	Inspecting Containers
docker events <container>	Containers Events
docker port <container>	Public Ports
docker top <container>	Running Processes
docker stats <container>	Container Resource Usage
docker diff <container>	Lists the changes made to a container.
docker logs <container>	Container Logs

Manipulate

Command	Description
docker exec -it <container-name-or-id> <shell-executable>	Shell des Dockers aufrufen. Shell Beispiel: /bin/bash
docker exec -it <container> bash	Connecting to container
docker stop <container>	Stop a container
docker restart <container>	Restart a container
docker rm <container>	Remove a container
docker port <container>	Shows container’s port mapping
docker top <container>	List processes
docker kill <container>	Kill a container
docker rename <oldName> <newName>	Renaming a Container

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 (host:container)
      --expose 5432          # expose a port to containers
  -P, --publish-all          # publish all ports
      --link container:alias # linking
  -v, --volume hostPath:containerPath    # mount (absolute paths needed)
  -e, --env NAME=hello       # env vars

Networking

Command	Description
docker network rm MyOverlayNetwork	Removing a network
docker network ls	Listing networks
docker network inspect MyOverlayNetwork	Getting information about a network
docker network connect MyOverlayNetwork nginx	Connecting a running container to a network
docker run -it -d --network=MyOverlayNetwork nginx	Connecting a container to a network when it starts
docker network disconnect MyOverlayNetwork nginx	Disconnecting a container from a network

Clean

Command	Description
docker system prune	Cleans up dangling images, containers, volumes, and networks (ie, not associated with a container)
docker system prune -a	Additionally, remove any stopped containers and all unused images (not just dangling images)
docker rmi <image>	Removes image

Compose

Command	Description
docker compose up -d	Lädt die Konfiguration der docker-compose.yml aus dem aktuellen Directory und fährt den Container hoch. Durch -d wird der Container im Hintergrund ausgeführt, und die Konsole verlässt den Container nach dem starten wieder
docker compose down	Fährt den Container herunter
docker compose kill	Erzwingt das herunterfahren des Dockers
docker compose pull	Lädt die neueste Version des Docker Images

docker-compose.yml

Mit dieser Datei können Docker Container konfiguriert werden, und die Konfiguration gespeichert werden.

Eine Beispieldatei für eine docker-compose.yml.

services:
  <service_name>:
    container_name: <container_name>
    image: <image_name>:<tag>
    pull_policy: <always|missing|never>
    restart: <no|always|on-failure|unless-stopped>
    hostname: <hostname>
    domainname: <domain>
    user: "<user>:<group>"
    group_add:
      - <group_id>
    entrypoint: ["<befehl>", "<arg1>", "<arg2>"]
    command: ["<befehl>", "<arg1>"]
    ports:
      - "<host_port>:<container_port>/<tcp|udp|sctp>:<ro/rw>"
    expose:
      - "<port>"
    volumes:
      - "<host_path>:<container_path>:<rw|ro>"
    environment:
      <VAR_NAME>: <VAR_VALUE>
    env_file:
      - <pfad/zur/.env>
    networks:
      - <network_name>
 
networks:
  <network_name>:
    driver: <bridge|overlay|host|none>
    driver_opts:
      <key>: <value>
    ipam:
      driver: <default>
      config:
        - subnet: <172.28.0.0/16>
          gateway: <172.28.5.254>
    external: <true|false>
    name: <netzwerk_name>
 
volumes:
  <volume_name>:
    driver: <local|nfs|...>
    driver_opts:
      <key>: <value>
    external: <true|false>
    name: <volumen_name>
 

Dockerfile

---

Instruction	Description
FROM <image>	Defines a base for your image.
RUN <command>	Executes any commands in a new layer on top of the current image and commits the result. RUN also has a shell form for running commands.
WORKDIR <directory>	Sets the working directory for any RUN, CMD, ENTRYPOINT, COPY, and ADD instructions that follow it in the Dockerfile.
COPY <src> <dest>	Copies new files or directories from <src> and adds them to the filesystem of the container at the path <dest>.
CMD <command>	Lets you define the default program that is run once you start the container based on this image. Each Dockerfile only has one CMD, and only the last CMD instance is respected when multiple exist.