Docker, Ceci N'Est Pas Une Introduction (APIHour #12)

Docker, l'une des technologies les plus en vogue ces derniers temps, permet de créer des conteneurs logiciels. Retour sur mon utilisation pour le développement mais également pour la production, avec en ligne de mire : une architecture micro-services, quelques principes 12 Factors et un déploiement en (presque) zéro-downtime.

Sources: https://github.com/willdurand-slides/docker-clermontech

Transcript

1. (Ceci N'Est Pas Une Introduction)
   William Durand ‑ December 16th, 2014
   

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2. Docker In A Nutshell
   

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3. Containers
   A container is an operating‑system level virtualization
   method that provides a completely isolated
   environment, simulating a closed system running on a
   single host.
   chroot, OpenVZ, Jail, LXC, etc.
   

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4. Containers vs VMs
   

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5. Docker
   Developed by Docker.inc (formerly DotCloud)
   Open platform for developing, shipping,
   and running applications
   Use as execution driver
   libcontainer
   

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6. Docker's Architecture
   Host
   Container 1
   Container 2
   Container 3
   Container ...
   Docker Client
   docker pull
   docker run
   docker ...
   Docker Index
   Docker Daemon
   

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7. The Plan
   Simple solution to deploy my application
   Idempotent and reliable process
   No need for rollbacks
   Targetting zero downtime
   Single host
   

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8. How?
   

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9. Methodology
   

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10. Twelve Factors
    One codebase tracked in revision control,
    many deploys
    Store config in the environment
    Keep development, staging, and production
    as similar as possible
    by
    The Twelve‑Factor App @aymericbrisse
    

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11. Infrastructure
    

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12. Services
    Reverse proxy: (+ )
    Backend: + + application
    Sessions are stored into
    Database (at some point...)
    Hipache Redis
    Nginx HHVM
    memcached
    

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13. Overall Architecture
    

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14. Application's fig.yml
    web:
    build: .
    # No support for `env-file` yet...
    # See: https://github.com/docker/fig/pull/665
    environment:
    - SYMFONY_ENV=dev
    - SYMFONY_DEBUG=1
    - SYMFONY__MEMCACHED_HOST=memcached
    - SYMFONY__MEMCACHED_PORT=11211
    - SYMFONY__SESSION_MEMCACHED_PREFIX=session
    - SYMFONY__SESSION_MEMCACHED_EXPIRE=604800
    links:
    - memcached
    - database
    

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15. Application's Dockerfile
    FROM debian:wheezy
    MAINTAINER William Durand
    ENV DEBIAN_FRONTEND noninteractive
    # Let APT know about HHVM repo...
    RUN apt-get update -y
    RUN apt-get install -y nginx hhvm supervisor
    # Configure Nginx, HHVM, Supervisor here...
    ADD . /app
    WORKDIR /app
    EXPOSE 80
    CMD [ "/usr/bin/supervisord" ]
    

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16. DNS
    example.org w www.example.org
    Configured at the DNS level. Faster than making
    this redirection using the load balancer.
    

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17. SSL
    Hipache listens on ports 80 and 443.
    Patched version of Hipache to redirect
    HTTP traffic to HTTPS. Sort of SSL offloading.
    ® willdurand/docker‑hipache
    

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18. Deploy
    

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19. 1. Build Artifact
    git archive --format tar --prefix myapp/ | (cd /tmp && tar xf -)
    Protip: use a Docker container to run build tools:
    cd /tmp/myapp
    docker run --rm -v `pwd`:/srv buildtools composer install
    docker run --rm -v `pwd`:/srv buildtools bundle install
    docker run --rm -v `pwd`:/srv buildtools bower install
    rm
    

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20. 2. Build Container (From Artifact)
    docker build -t myapp:latest .
    

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21. 3. Push It
    docker push
    q Or whatever that makes the image
    available on the production server.
    

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22. 4. Retrieve Running Containers
    RUNNING_CIDS=$(docker ps | grep web | cut -d ' ' -f 1)
    

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23. 5. Run The New Container
    fig run -d --no-deps --rm web
    † Booting the container may take a few seconds, wait.
    

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24. 6. Register It As Backend
    IP=$(docker inspect --format='{{ .NetworkSettings.IPAddress }}' )
    fig run --rm rediscli rpush frontend:www.example.com "http://$IP:80"
    # fig.yml
    rediscli:
    image: redis
    entrypoint: [ redis-cli, -h, redis ]
    links:
    - redis
    

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25. 7. Unregister Previous Backends
    For each container id CID in $RUNNING_CIDS, do:
    IP=$(docker inspect --format='{{ .NetworkSettings.IPAddress }}' )
    fig run --rm rediscli lrem frontend:www.example.com 0 "http://$IP:80"
    † New backend is up and serves requests. However,
    previous backends may still process requests. Wait.
    

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26. 8. Stop Previous Containers
    For each container id CID in $RUNNING_CIDS, do:
    docker stop
    

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27. 9. Tag A Release (And Profit!)
    

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28. Testing
    

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29. Like , but better!
    Apache Bench
    ® tarekziade/boom
    

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30. 1. Run boom
    boom https://www.example.org/ -n 2000 -c 50
    Server Software: nginx/1.2.1
    Running GET https://www.example.org/
    Running 2000 times per 50 workers.
    [================================================================>.] 99% Done
    -------- Results --------
    Successful calls 2000
    Total time 137.1827 s
    Average 6.7114 s
    Fastest 2.3701 s
    Slowest 9.4738 s
    Amplitude 7.1037 s
    -------- Status codes --------
    Code 200 2000 times.
    

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31. 2. Deploy
    fab deploy --hide=running,stdout,stderr
    ---> Deploying branch "awesome-feature"
    ---> Building artifact
    ---> Artifact id is: "build-8fe47fc"
    ---> Pushing artifact to the server
    ---> Building container
    ---> Finding running containers
    ---> Starting new container
    ---> Waiting while container is booting
    ---> Registering new backend to Hipache
    ---> Unregistering the previous backends from Hipache
    ---> Waiting before stopping the previous backends
    Done.
    q I use .
    Fabric
    

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32. 3. Monitor
    Elasticsearch, Logstash, Kibana
    +
    Logstash Forwarder (lumberjack)
    ® willdurand/docker‑elk
    ® willdurand/docker‑logstash‑forwarder
    

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34. Thank You.
    Questions?
    ¾
    ®
    ¬
    williamdurand.fr
    github.com/willdurand
    twitter.com/couac
    

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35. Bonus
    

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36. Fig & Environments
    Keep development, staging, and
    production as similar as possible
    X. Dev/prod parity — 12 Factors
    # fig.yml.dist
    web:
    # In PRODUCTION, the line below MUST be COMMENTED:
    build: .
    # In PRODUCTION, the line below must be UNCOMMENTED:
    # image: myapp
    # ...
    

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37. Data Only Containers
    Data, logs, etc. MUST live in data only containers:
    # fig.yml
    redis:
    image: redis
    volumes_from:
    - dataredis
    dataredis:
    image: busybox
    volumes:
    - /data
    Wanna backup? ė
    docker run --rm \
    --volumes-from dataredis \
    -v $(pwd):/backup \
    busybox \
    tar cvf /backup/dataredis.tgz /data
    

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