TechEd 2018, Introduction to Docker

https://ondrej-sika.cz/blog/2018/teched/

Transcript

1. Introduction to Docker
   #TechEdDevCon
   Ondrej Sika
   ondrej@ondrejsika.com
   @ondrejsika
   TechEd,
   Prague, 17. 5. 2018
   

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2. Agenda
   - What is a Docker?
   - Usage
   - Containers
   - Images
   - Docker Registry
   - Composites
   - Swarm
   

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3. What is Docker?
   

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4. What is Docker?
   Docker is an open-source project
   that automates the deployment of
   applications inside software
   containers. ...
   Docker containers wrap up a piece
   of software in a complete filesystem
   that contains everything it needs to
   run: code, runtime, system tools,
   system libraries – anything you can
   install on a server.
   

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5. Containers vs virtualization
   

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6. Virtualization
   A VM is an abstraction of physical
   hardware. Each VM has a full server
   hardware stack from virtualized
   BIOS to virtualized network
   adapters, storage, and CPU.
   That stack allows run any OS on
   your host but it takes some power.
   

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7. Containers
   Containers are abstraction in linux
   kernel, just proces, memory,
   network, … namespaces.
   Containers run in same kernel as
   host - it is not possible use different
   OS or kernel version, but containers
   are much more faster than VMs.
   

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8. History of
   containers
   - 1979 - Chroot
   - 2000 - BSD Jails
   - 2001 - VServer
   - 2004 - Solaris Containers
   - 2005 - OpenVZ
   - 2006 - Process Containers
   - 2008 - LXC
   - 2013 - Docker
   

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9. Advantages - Performance
   - Management
   - Containers distribution
   

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10. Disadvantages - Security
    - One kernel / "Linux only"
    

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11. Usage
    - Almost everywhere
    - Development, Testing,
    Production
    - Better deployment process
    - Separates running applications
    

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12. Work with
    Cluster managements
    - Swarm (Native)
    - Open Stack
    - Kubernetes
    

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13. Installation
    

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14. https://docs.docker.com/engine/installation/
    

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15. Test the installation
    docker run hello-world
    ...
    Hello from Docker!
    This message shows that your installation
    appears to be working correctly.
    

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16. Basic Usage
    

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17. Image and
    Container
    An image is an inert, immutable, file
    that's essentially a snapshot of a
    container. Images are created with
    the build command, and they'll
    produce a container when started
    with run. Images are stored in a
    Docker registry..
    

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18. Help
    docker
    docker help
    docker help
    # eg. docker help run, docker help help
    

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19. System wide info
    docker version # print version
    docker system info # system vide information
    docker system df # docker disk usage
    docker system prune # cleanup unused data
    

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20. Docker Images
    docker image ls # list all images
    docker image ls -q # quiet output, just IDs
    docker image rm # remove image
    docker image pull # pull from registry
    docker image push # push to registry
    docker tag image # add new tag
    

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21. Docker Run
    docker run []
    # Eg.:
    docker run hello-world
    docker run debian:8 cat /etc/os-release
    docker run debian:9 cat /etc/os-release
    docker run -ti debian
    

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22. Common Docker Run Params
    --name
    -d - run as daemon
    -ti - map TTY a STDIN (for bash eg.)
    -e = - set ENV variable
    -h - set hostname
    -u - run command by specific user
    --rm - remove container after stop
    

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23. Containers
    docker ps - list containers
    docker start
    docker stop
    docker restart
    docker logs # show STDOUT & STDERR
    docker rm # remove container
    

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24. List containers
    docker ps - list running containers
    docker ps -a - list all containers
    docker ps -a -q - list IDs of all containers
    # Eg.:
    docker rm -f $(docker ps -a -q)
    

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25. Docker Exec
    docker exec
    -d - run command as daemon
    -e = - set ENV variable
    -ti - map TTY a STDIN (for bash eg.)
    -u - run command by specific user
    # Eg.:
    docker exec my-debian ls
    

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26. Docker Logs
    docker logs [-f]
    # Eg.:
    docker logs my-debian
    docker logs -f my-debian # following
    

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27. Docker Inspect
    Get lots of information about
    container in JSON.
    docker inspect
    

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28. Docker Volumes
    Volumes are persistent data storage
    for containers.
    Volumes can be shared between
    containers and data are written
    directly to host.
    

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29. Volumes
    docker run -ti -v /data debian
    docker run -ti -v my-volume:/data debian
    docker run -ti -v $(pwd)/my-data:/data debian
    

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30. Port Forwarding Docker can forward specific port
    from container to host
    

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31. Port forwarding
    docker run -p :
    # eg.:
    docker run -ti -p 8080:80 nginx
    

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32. Own Images
    

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33. Dockerfile
    Dockerfile is preferred way to
    create images.
    Dockerfile defines each layer of
    image by some command.
    To make image use command
    docker build
    

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34. Dockerfile
    FROM - define base image
    MAINTAINER - set maintainers name &
    email
    RUN - run command and save as layer
    COPY - copy file or
    directory to image layer
    ADD - instead of copy,
    archives added by add are extracted
    

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35. Dockerfile
    ENV - set ENV variable
    USER - switch user
    WORKDIR - change working directory
    VOLUME - define volume
    ENTRYPOINT - command, run on container
    starts
    CMD - parameters for entrypoint
    

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36. .dockerignore
    Ignore files for docker build process.
    Similar to .gitignore
    

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37. .dockerignore
    # comment
    */temp*
    */*/temp*
    temp?
    

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38. Build Image from Dockerfile
    docker build -t
    docker build -f -t
    docker tag
    # eg.:
    docker build -t my-image .
    

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39. Example
    

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40. app.py
    import os
    from flask import Flask
    from redis import Redis
    app = Flask(__name__)
    redis = Redis('redis')
    hostname = os.environ.get('HOSTNAME')
    @app.route("/")
    def index():
    return '%s %d' % (hostname, redis.incr('counter'))
    app.run(host='0.0.0.0', port='80')
    

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41. requirements.txt
    flask
    redis
    

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42. Dockerfile
    FROM python:3.6-alpine
    COPY requirements.txt /app/requirements.txt
    WORKDIR /app
    RUN pip install -r requirements.txt
    COPY . /app
    CMD python app.py
    

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43. https://github.com/ondrejsika/teched18
    

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44. Run
    docker build -t teched18 .
    docker run --name redis -d redis:alpine
    docker run -p 80:80 --link redis teched18
    

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45. Docker Registry
    

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46. What is
    Docker Registry?
    A service responsible for hosting and
    distributing images.
    The default registry is the Docker
    Hub.
    GitLab contains Docker Registry
    from version 8.
    

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47. What is
    Docker Hub?
    Docker Hub is default public docker
    registry.
    You can host unlimited free images.
    Docker Hub is source of our base
    images.
    

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48. Docker registry
    docker login - Login to Docker Registry
    docker logout - Logout from Docker Registry
    docker pull - download image from registry
    docker push - upload image to registry
    

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49. Image name format
    # Official image from Docker Inc on Docker Hub
    debian
    # Image in user namespace on Docker Hub
    ondrejsika/debian
    # Image on own Docker Registry (reg.istry.cz)
    reg.istry.cz/debian
    

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50. Docker Compose
    

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51. What is
    Docker Compose?
    Compose is a tool for defining and
    running multi-container Docker
    applications.
    With Compose, you use a Compose
    file to configure your application's
    services.
    

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52. Install Docker Compose
    

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53. https://docs.docker.com/compose/install/
    https://docs.docker.com/compose/completion/
    

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54. Compose File
    A docker-compose.yml file is a
    YAML file that defines how Docker
    containers should behave in
    production.
    

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55. Example Compose File
    version: '3'
    services:
    counter:
    build: .
    image: reg.istry.cz/counter
    ports:
    - 80:80
    redis:
    image: redis:alpine
    

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56. https://docs.docker.com/compose/compose-file/
    

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57. Service Service is a container running and
    managed by Docker Compose.
    

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58. Build
    services:
    app:
    build: .
    services:
    app:
    build:
    context: ./app
    dockerfile: Dockerfile-prod
    image: myapp
    

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59. Image
    services:
    app:
    image: redis:alpine
    

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60. Port forwarding
    services:
    app:
    ports:
    - 8000:80
    

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61. Volumes
    services:
    app:
    volumes:
    - /data1
    - data:/data2
    - ./data:/data3
    

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62. Environment variables
    services:
    app:
    environment:
    RACK_ENV: development
    SHOW: 'true'
    SESSION_SECRET:
    services:
    app:
    environment:
    - RACK_ENV=development
    

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63. Command, Entrypoint
    services:
    app:
    entrypoint: ["python", "app.py"]
    command: ["80"]
    

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64. Deploy
    services:
    app:
    deploy:
    placement:
    constraints: [node.role == manager]
    services:
    app:
    deploy:
    mode: replicated
    replicas: 4
    

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65. Create a Composite
    

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66. Create docker-compose.yml
    version: '3'
    services:
    app:
    build: .
    image: reg.istry.cz/teched18
    ports:
    - 80:80
    redis:
    image: redis:alpine
    

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67. Compose Commands
    

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68. Basic Compose Commands
    docker-compose config
    docker-compose help
    docker-compose ps
    docker-compose exec
    docker-compose version
    docker-compose logs [-f] []
    

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69. Build Compose
    docker-compose build
    docker-compose build --no-cache
    

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70. Run Compose
    docker-compose up
    docker-compose up -d
    # Missing images will be downloaded or
    builded
    

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71. Compose Up Arguments
    -d - run as daemon
    --force-recreate - always create new cont.
    --build - build on every run
    --no-build - don't build, even images not
    exist
    --remove-orphans
    --abort-on-container-exit
    

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72. Manage Compose
    docker-compose start []
    docker-compose stop []
    docker-compose restart []
    docker-compose kill []
    

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73. Remove Compose
    docker-compose down
    # stop and remove compose
    

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74. Docker Swarm
    

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75. What is
    Docker Swarm?
    A native clustering system for
    Docker. It turns a pool of Docker
    hosts into a single, virtual host using
    an API proxy system. It is Docker's
    first container orchestration project
    that began in 2014. Combined with
    Docker Compose, it's a very
    convenient tool to manage
    containers.
    

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76. Create a Swarm
    

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77. Initialize Swarm
    docker swarm init --advertise-addr
    # Eg.:
    docker swarm init --advertise-addr 192.168.99.100
    

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78. Add Worker to Swarm
    docker swarm join --token :2377
    # Eg.:
    docker swarm join \
    --token SWMTKN-1-49nj1cmql0...acrr2e7c \
    192.168.99.100:2377
    

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79. Manage Swarm
    

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80. Manage Swarm Nodes
    docker node ls - list nodes
    docker node rm - remove node from
    swarm
    docker node inspect
    docker node ps []- list swarm task
    docker node update ARGS
    

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81. Deploy to Swarm
    

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82. Build & Push
    # Build
    docker-compose build
    # Push
    docker-compose push
    

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83. Deploy App to Swarm
    # run
    docker stack deploy \
    --compose-file docker-compose.yml \
    teched18
    

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84. Test It!
    

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85. Manage Services
    docker stack ls
    docker stack services
    docker stack ps
    docker stack rm
    

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86. Scale the Service
    docker service scale =
    # Eg.:
    docker service scale teched18_app=5
    

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87. Test It!
    

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88. Thank you
    Ondrej Sika
    email: ondrej@ondrejsika.com
    twitter: @ondrejsika
    linkedin: /in/ondrejsika/
    slides: https://ondrej-sika.cz/blog/2018/teched
    

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