docker deployment

current deployment

      1. Build  an  DEB  
      2. Deploy DEB  to test env.
      3. Run unit and integration tests
      4. Deploy to each node in production (via chef)

    Current deployment

      • Development ENV could be not same Production ENV and Test
        • Even if your code is perfect, deployment might fall
      • More work done  on start-up (via chef-boot)  
        • Not FAST!
      • Slower,error-prone , runtime dependency (chef,apt,pypi)
        • Chef or Debian repo. could be down


    Deployment w/ Docker

      • Build docker container for application 
        • Dependencies in Dockerfile
        • Without  config/env
      • Build/Run/Test container with TEST env. (CI tool)
      • Push docker container image to registry
      • Pull docker container on each node 
      • "Paramertized containers" using environment variables
      • Run docker container 

    Common environment 


    config

      
    An app’s config is everything that is likely to vary between deploys (staging, production, developer environments, etc). 

    • Resource handles to the database, Memcached, and other backing services
    • Credentials to external services such as Amazon S3 or Twitter
    • Per-deploy values such as the canonical hostname for the deploy



    Config 

    "The twelve-factor app stores config in environment variables (often shortened to env vars or env). Env vars are easy to change between deploys without changing any code; unlike config files, there is little chance of them being checked into the code repo accidentally; and unlike custom config files, or other config mechanisms such as Java System Properties, they are a language- and OS-agnostic standard."


    From:  http://12factor.net/config

    "Paramertized containers" using environment variables

    FiG : Fast, isolated development environments using Docker

     http://orchardup.github.io/fig/
     Dockerfile
    FROM orchardup/python:2.7
ADD . /code
WORKDIR /code 
RUN pip install -r requirements.txt

    fig.yml
    web:
  build: .
  command: python app.py
  ports:
   - "5000:5000"
  volumes:
   - .:/code
  links:
   - redis
redis:
  image: orchardup/redis 

    FIG : FAST, ISOLATED DEVELOPMENT ENVIRONMENTS USING DOCKER

    app.py
    from flask import Flask
from redis import Redis
import os
app = Flask(__name__)
redis = Redis(
    host=os.environ.get('REDIS_1_PORT_6379_TCP_ADDR'),
    port=int(os.environ.get('REDIS_1_PORT_6379_TCP_PORT'))
)

@app.route('/')
def hello():
    redis.incr('hits')
    return 'Hello World! I have been seen %s times.' % redis.get('hits')

if __name__ == "__main__":
    app.run(host="0.0.0.0", debug=True)

    FIG : FAST, ISOLATED DEVELOPMENT ENVIRONMENTS USING DOCKER

    fig.yml (for production?)
    web:
  build: .
  command: python app.py
  ports:
   - "5000:5000"
  environment:
   REDIS_1_PORT_6379_TCP_ADDR : 192.168.100.45
   REDIS_1_PORT_6379_TCP_PORT : 6379

    Connector agnostic containers


    Cross-Host linking using Ambassador Containers
    https://docs.docker.com/articles/ambassador_pattern_linking/

    Linking containers is only in same host (now)

    (consumer) --> (redis-ambassador) ---network---> (redis-ambassador) --> (redis)


    Docker Deployment Tools

    Docker Performance

    Startup Time

    Building images

    docker performance

    Installing image

    docker benchmark


    docker performance

    • CPU Performance 
      • = Native Performance
    • Memory Performance 
      • = a few % shaved  off  for (optional) accounting
    • Network and Disk I/O Performance 
      • = small overhead  ; can be reduced to zero

    docker Misconception

    https://devopsu.com/blog/docker-misconceptions/
    " Your systems need to already be in fine working order before you even consider using Docker in production."

    • secured least-privilege access (key based logins, firewalls, fail2ban, etc)
    • restorable secure off-site database backups
    • automated system setup (using Ansible, Puppet, etc)
    • automated deploys
    • automated provisioning
    • monitoring of all critical services
    • and more (documentation, etc)
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