urbanonymous / minimal_docker_app

Docker guide for reference

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minimal_docker_app

Simple app with a complete easy-guide for docker TODO: networks (docker<->docker, docker<->vps, docker<->world)

DOCKER GUIDE

PART 1 - INSTALLATION

  • Installation: In ubuntu 16.04:

    sudo apt-get update
    sudo apt-key adv --keyserver hkp://p80.pool.sks-keyservers.net:80 --recv-keys 58118E89F3A912897C070ADBF76221572C52609D
    sudo apt-add-repository 'deb https://apt.dockerproject.org/repo ubuntu-xenial main'
    sudo apt-get update
    apt-cache policy docker-engine
    

    Output:

    docker-engine:
    Installed: (none)
    Candidate: 17.05.0~ce-0~ubuntu-xenial (version could change)
    ...
    

    Then...

    sudo apt-get install -y docker-engine
    sudo systemctl status docker
    

    Output:

    docker.service - Docker Application Container Engine
    Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled)
    Active: active (running) since Sun 2018-08-19 13:35:15 UTC; 24s ago
    ...
    

    After that...

    control+C
    sudo docker info
    

    Output:

    Containers: 0
    Running: 0
    Paused: 0
    Stopped: 0
    Images: 0
    Server Version: 17.05.0-ce
    ...
    
  • Testing:

    sudo docker run hello-world
    

    Output:

    Unable to find image 'hello-world:latest' locally
    latest: Pulling from library/hello-world
    9db2ca6ccae0: Pull complete
    Digest: sha256:4b8ff392a12ed9ea17784bd3c9a8b1fa3299cac44aca35a85c90c5e3c7afacdc
    Status: Downloaded newer image for hello-world:latest
    
    Hello from Docker!
    This message shows that your installation appears to be working correctly.
    ...
    
    sudo docker image ls
    

    Output:

    REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
    hello-world         latest              2cb0d9787c4d        5 weeks ago         1.85kB
    
    sudo docker container ls --all
    

    Output:

    CONTAINER ID        IMAGE               COMMAND             CREATED              STATUS                          PORTS               NAMES
    5b71cee88939        hello-world         "/hello"            About a minute ago   Exited (0) About a minute ago                       relaxed_bhabha
    
  • Cheatsheet (from docker docs):

    ## List Docker CLI commands
        docker
        docker container --help
    
    ## Display Docker version and info
        docker --version
        docker version
        docker info
    
    ## Execute Docker image
        docker run hello-world
    
    ## List Docker images
        docker image ls
        docker images
    
    ## List Docker containers (running, all, all in quiet mode)
        docker container ls
        docker container ls --all
        docker container ls -aq
    

PART 2 - SETTING UP

  • Creating a Dockerfile:

    Dockerfile: (Set of rules/actions/configurations in a container/image)

    # Use a Python runtime as a parent image
    FROM frolvlad/alpine-python3
    
    # Set metadata about the maintainer of the image
    LABEL maintainer="Urbano Gutierrez <urbano@fatwhale.io>"
    
    # Set the working directory to /app
    WORKDIR /app
    
    # Copy the current directory contents into the container at /app
    ADD . /app
    
    # Update the system
    RUN apk update && apk upgrade && \
        apk add --no-cache \
        bash \
        git \
        openssh \
        build-base \
        make \
        python3-dev
    
    # Install any needed packages specified in requirements.txt
    RUN pip install --upgrade pip
    RUN pip install -r requirements.txt
    
    # Run main.py when the container is ready
    CMD ["python", "-u", "main.py"]
  • Building the container/image:

    With our application inside a folder ex: (project_1)

    You have few ways to have this project here, clonning it from github, uploading using sftp or ftp ...

    cd project_1
    ls project_1
    

    Output:

    Dockerfile  main.py  Readme.md  requirements.txt
    
    docker build -t atagfortheproject .
    

    Output:

    Sending build context to Docker daemon  5.632kB
    Step 1/7 : FROM frolvlad/alpine-python3
    latest: Pulling from frolvlad/alpine-python3
    8e3ba11ec2a2: Pull complete
    83d8aa72cb9b: Pull complete
    Digest: sha256:8d9f2a8e577acac8cc1f6633dbd7731fa764a14e6905e93d8deac2895fe0ceff
    Status: Downloaded newer image for frolvlad/alpine-python3:latest
    ---> a056c2d555fe
    Step 2/7 : LABEL maintainer "Urbano Gutierrez <@urbiGT>"
    ---> Running in 8bcccc02ca05
    ---> 98a0c6f5e85b
    Removing intermediate container 8bcccc02ca05
    Step 3/7 : WORKDIR /app
    ---> 38586ee4b707
    Removing intermediate container f8445b53b9cf
    Step 4/7 : ADD . ./app
    ---> 6f21c6071c75
    Removing intermediate container 0aaf3d89e959
    Step 5/7 : RUN apk update && apk upgrade &&     apk add --no-cache     bash     git     openssh     build-base     make     python3-dev
    ---> Running in 6a00f7e2c8ea
    fetch http://dl-cdn.alpinelinux.org/alpine/v3.8/main/x86_64/APKINDEX.tar.gz
    ...
    Removing intermediate container 2c68a17cec27
    Step 8/8 : CMD python main.py
    ---> Running in 903ab59926bd
    ---> 6a51ac14aba4
    Removing intermediate container 903ab59926bd
    Successfully built 6a51ac14aba4
    Successfully tagged projectapp:latest
    

    used projectapp as tag, numbers/ids changes

  • ---OPTIONAL TO HAVE ACCESS FROM OTHER MACHINES---

    • Log-in docker:

      register on https://hub.docker.com/

      create a repository ex: test-app (set it as private)

      sudo docker login
      

      Output:

      Login with your Docker ID to push and pull images from Docker Hub. If you don't have a Docker ID, head over to https://hub.docker.com to create one.
      Username: your-username
      Password:
      Login Succeeded
      
    • Check the image ID:

      sudo docker images
      

      Output:

          REPOSITORY              TAG       IMAGE ID         CREATED           SIZE
          yourcontainername     latest    yourimageID     3 minutes ago     1.975 GB
          ...
      
    • Push image to docker:

      sudo docker tag yourimageID yourusername/testapp:yourversiontag
      sudo docker push yourusername/testapp
      

      Output:

          The push refers to a repository [docker.io/urbanon/testapp]
          874792b6ae85: Pushed
          471984be847f: Pushed
          b367ab4e7128: Pushed
          5a70acc82f16: Pushed
          af57e8fffa65: Pushed
          f4c48043d646: Mounted from frolvlad/alpine-python3
          73046094a9b8: Mounted from frolvlad/alpine-python3
          yourversiontag: digest: sha256:777bdec7f6d3f2c3d21301bc7c98d3c0c9d661d93b56daf0512721b9e5cc65bf size: 1787
      

      used yourversiontag as tag, 6a51ac14aba4 as IMAGEID

      care, this uses a lot of bandwidth

    • Download a image:

      after using sudo docker login in another vps

      sudo docker pull yourusername/yourappname:yourversiontag
      

      Output:

      yourversiontag: Pulling from urbanon/testapp
      Digest: sha256:777bdec7f6d3f2c3d21301bc7c98d3c0c9d661d93b56daf0512721b9e5cc65bf
      Status: Image is up to date for urbanon/testapp:yourversiontag
      

      used yourversiontag as tag, testapp as app name, urbanon as account, same VPS (Status: Image is up to date... not downloaded)

PART 3 - RUNNING

  • Run a image:

    sudo docker run -d urbanon/testapp:yourversiontag
    
  • Get logs:

    sudo docker logs containerID
    

    Output:

      `Heey, it should be working`
    

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Docker guide for reference


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