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

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

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William Durand

December 15, 2014
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  1. 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.
  2. 5.

    Docker Developed by Docker.inc (formerly DotCloud) Open platform for developing,

    shipping, and running applications Use as execution driver libcontainer
  3. 6.

    Docker's Architecture Host Container 1 Container 2 Container 3 Container

    ... Docker Client docker pull docker run docker ... Docker Index Docker Daemon
  4. 7.

    The Plan Simple solution to deploy my application Idempotent and

    reliable process No need for rollbacks Targetting zero downtime Single host
  5. 8.
  6. 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
  7. 12.

    Services Reverse proxy: (+ ) Backend: + + application Sessions

    are stored into Database (at some point...) Hipache Redis Nginx HHVM memcached
  8. 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
  9. 15.

    Application's Dockerfile FROM debian:wheezy MAINTAINER William Durand <william.durand1@gmail.com> 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" ]
  10. 16.

    DNS example.org w www.example.org Configured at the DNS level. Faster

    than making this redirection using the load balancer.
  11. 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
  12. 18.
  13. 19.

    1. Build Artifact git archive --format tar --prefix myapp/ <SHA>

    | (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 <USELESS/TEMP FILES>
  14. 21.

    3. Push It docker push q Or whatever that makes

    the image available on the production server.
  15. 23.

    5. Run The New Container fig run -d --no-deps --rm

    web † Booting the container may take a few seconds, wait.
  16. 24.

    6. Register It As Backend IP=$(docker inspect --format='{{ .NetworkSettings.IPAddress }}'

    <CID>) fig run --rm rediscli rpush frontend:www.example.com "http://$IP:80" # fig.yml rediscli: image: redis entrypoint: [ redis-cli, -h, redis ] links: - redis
  17. 25.

    7. Unregister Previous Backends For each container id CID in

    $RUNNING_CIDS, do: IP=$(docker inspect --format='{{ .NetworkSettings.IPAddress }}' <CID>) 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.
  18. 26.

    8. Stop Previous Containers For each container id CID in

    $RUNNING_CIDS, do: docker stop <CID>
  19. 28.
  20. 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.
  21. 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
  22. 32.

    3. Monitor Elasticsearch, Logstash, Kibana + Logstash Forwarder (lumberjack) ®

    willdurand/docker‑elk ® willdurand/docker‑logstash‑forwarder
  23. 33.
  24. 35.
  25. 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 # ...
  26. 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