Docker

• Commands
  • docker version
  • docker ps

    List all running containers

  • docker ps --all

    List of all of containers we have ever created

  • docker run hello-world
    Start up a new container using an image hello-world
  
  
  • docker run = docker create + docker start

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  • docker create hello-world

    Shows the id of the container that is just created

    docker start -a <container id>

    Executes the hello-world inside this container

    -a means attach to the container and watch out of the container and print the output of the container

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  • Get logs from a container that have been emitted from the container (even if it has finished to run)

    docker logs <container id>

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  • docker create hello-world

    docker start <container id>

    docker logs <container id>

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  • Delete stopped containers (cleans disk space)

    docker system prune

    To see that it was deleted:

    docker ps --all

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  • Default command override

    docker run busybox echo hi there

    docker run busybox echo buy there

    docker run busybox ls <-- prints all the files and folders inside the given directory

  • docker run busybox ping google.com

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  • docker create busybox ping google.com

    docker start <container id>

    docker logs <container id>

    docker ps

    docker stop <process id from docker ps command> <-- has 10 seconds to shut down gracefully. After that docker kill it

    docker start <process id from docker ps command>

    docker kill <process id from docker ps command>

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  • Docker exec

    Execute an additional command in a container

    docker exec -it <container id> <command>

    Same as

    docker exec -i -t <container id> <command>

    • docker - reference the Docker client
    • exec - run another command
    • -it - allow us to provide input to the container
    • <container id> - id of the container
    • <command> - command to execute
    • ---
    • -i - attach our terminal to the STDIN channel of the running process (here redis-cli). Any staff that i type gets directly into STDIN of redis-cli
    • -t - show things pretty formatted
  
  
• Docker with Redis

  • docker run redis

  • At the other terminal:

    docker ps

    docker exec -it <container id> <command>

    docker exec -it <container id> redis-cli

    OR

    winpty docker exec -it <container id> redis-cli

    set myvalue 5

    get myvalue

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• Getting a Command Prompt In a Container

  Example: Docker with Redis

  • docker run redis

  • At the other terminal:

    docker ps

    docker exec -it <container id> sh

    <--- sh is a shell OR

    winpty docker exec -it <container id> sh

  • To get out of the container press on ^C or ^D or type exit

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• Starting with the shell

  • docker run -it busybox sh

  • Inside the shell we may run

    ping google.com

    echo my message

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• Goal: Create an image that runs redis-server
  • mkdir redis-image
  • cd redis-image
  • code . <-- starts Visual Code editor
  • Create Dockerfile under the redis-server
  • Specify a base image
  • Run some commands to install additional programs
  • Specify a command to run on container startup

  •               # Use and existing docker image as a base
                  
                  # Download and install a dependency
                  
                  # Tell the image what to do when it starts as a container
                

  ---

  •               # Use and existing docker image as a base
                  FROM alpine
    
                  # Download and install a dependency
                  RUN apk add --update redis
    
                  # Tell the image what to do when it starts as a container
                  CMD ["redis-server"]
                

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  • Build

    docker build .

  • Run

    docker run <image id>

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• Tagging an Image

  docker build -t <your docker id>/<Repo / Project name>: <latest or version number> <. or directory of files/folders to use for the build >

• • Example:

    docker build -t rayalevinson/redis:latest .

  • Start up the container

    docker run rayalevinson/redis

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• Manually Image Generation with Docker Commit (but better use Dockerfile instead)
  • docker run -it alpine sh
  OR
  • winpty docker run -it alpine sh
  • apk add --update redis
  • At the other terminal:
    • docker ps
    • Get the id iof the running container

    • docker commit -c 'CMD ["redis-server"]' CONTAINERID

      If you are a Windows user you may get an error like "/bin/sh: [redis-server]: not found" or "No Such Container" see below

    • docker commit -c "CMD 'redis-server'" CONTAINERID
    • docker run CONTAINERID

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• Apache HTTP Server - httpd docker container run -d -p 8081:80 --name myapache httpd

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• Build image from Dockerfile $ docker image build -t nginx-website
• the equivalent of '${pwd}' on windows cmd is '%cd%'