Docker - Building Happier Dev environments

Given at Oxford Docker user group 11th Nov 2015

Transcript

1. Building reproducible dev environments with Docker @grahamgilchrist
2. Scenario 1 - The old project
3. Scenario 2 - The new member of staff Image credit: Paul Inkles https://www.flickr.com/photos/dumfstar/8553473662
4. Scenario 3 - The missing documentation
5. Scenario 4 - Different hardware, different OS
6. The problem • Large number of projects and variations on environments • Different hardware, operating systems and software versions trying to run same project • Environment setup in installation guide is forgotten or becomes out of date • All these things take up your time to maintain, often fixing the same issue on multiple machines
7. How do we keep the environments consistent and automate this boring job? Image credit: Steve Jurvetson https://www.flickr.com/photos/jurvetson/9690512888/
8. We want a solution that: 1. Stores environment config versioned with project code 2. Makes everyone use the same environment 3. Is reproducible from scratch 4. Automate the build process
9. + docker compose
10. Advantages of Docker over VM • Run speed • Build speed (image and build step caching) • Disk space - economical re-use of base system images etc. • Re-use of common services between projects • Large resource of pre-built community images setup via the docker hub image registry
11. Typical web project > docker-compose up project docker-compose.yml
12. python docker-compose.yml python: build: python/ command: manage.py runserver environment: DATABASE_URL: 'postgres://dbname@db/postgres' volumes: - ./python:/usr/src/app links: - db ports: - "8000:8000" db: image: postgres:9.3 ports: - "5432:5432"
13. python Dockerfile FROM python:3.4.3 # We add libmemcached from debian repositories RUN apt-get update && \ apt-get install -y \ libmemcached-dev \ && rm -rf /var/lib/apt/lists/* RUN mkdir -p /usr/src/app WORKDIR /usr/src/app COPY requirements.txt /usr/src/app/ RUN pip install -r requirements.txt
14. NodeJS docker-compose.yml grunt: build: node/ volumes: - ./web:/usr/src/app command: grunt bower: image: blinkmobile/bower:1.3.12 environment: bower_allow_root: true bower_analytics: false working_dir: /data volumes: - ./web:/data
15. How is it working out for us? Much higher bus factor Saving time Image credits: Tom Page https://www.flickr.com/photos/tompagenet/6935847473/ Steve Collis https://www.flickr.com/photos/swampa/8105520673/
16. Outstanding issues • Mac OS - not native ◦ slow for disk access via volume mounts • SSH issues ◦ rsync, ssh ◦ installing packages via github ssh auth • Learning curve for 'the docker way' ◦ Separation concepts are hard and totally new to most devs. ◦ Hard to get people to configure it themselves
17. Future improvements Identical dev / Deployment setup Issues on Mac OS Image credit: Steve Jurvetson https://www.flickr.com/photos/jurvetson/3327872958
18. Thanks! Final thoughts @grahamgilchrist