Development with Docker Engine and Compose
Zak B. Elep
zakame@zakame.net
Created: 2017-12-05 Tue 21:06
https://github.com/zakame/dscl-devday-docker-compose
About Me
- @zakame on GitHub, Twitter, FB
- Goon from the Philippine Linux Users Group
- Co-organizer, Docker Manila Meetup group
- Hacks on Perl, Docker, Emacs
What's this for?
- Short intro on Docker
- Assumes a developer audience (this is DSCL DevDay after all…)
- Assumes some familiarity with server infra (for the ops people at the back…)
Why Docker?
- Distribution
- Maintenance
- Development
The Problem
"How can I share my work with others while making it easy for them to change it?"
Distribution
- Software systems as containers
- (Mostly) standalone systems (especially for exotic setups)
- (Mostly) less chance of incompatibilities/inconsistencies
Maintenance
- Growing from "pet to cattle" setups
- Reducing moving targets (e.g. external dependencies and/or hybrid OS requirements)
- Redundancy (e.g. blue-green deployments)
Development
- Builds up on distribution and maintenance merits
- Correlate code history with system history (e.g. git vs docker commits)
- Leverage other solutions (e.g. configuration management/deployment/orchestration tools)
Containers
Operating-system-level virtualization
Containers vs Virtual Machines
- Operating-system-level vs hardware-abstraction-level
- Containers can run under VMs (and often do,) but not usually the other way around
- Containers depend on OS features (Linux)
Other Container implementations/tools
- Linux Containers (LXC)
- plain Unix chroot
- FreeBSD jails
- Solaris Zones
Docker Plaform
Docker Engine
- The "heart" of the Docker ecosystem
- Used to be just a big front-end for the Linux containers
- Now uses libcontainer to front-end for implementations
Demo: A simple CLI app container
Docker Compose
- Arrange containers into services
- Express software systems in terms of services, networks, and volumes
- Adapt systems to different environments (dev vs prod) via composition of configuration