Docker in Production
TL;DR
- Containerization: Package everything into a container which makes it easy for anyone to “transport” this container.
- Container’s advantages: Runs in isolation and in virtualized systems.
- Containers will run through container engines, such as Docker.
- Docker Images: Immutable Layers that build on top of each other.
- Don’t use Docker containers like full blown VMs. Run a single process/service in each Docker container
Full Version
Challenges with modern architectures:
- Multiple tech stacks
- Lots of moving parts
- Complex infrastructure
- Increased released frequency
- Teams unboarding
Containerization: Package everything into a container (depenencies, code etc), which makes it easy for anyone to “transports” this container.
Deploying on VM is good for isolation, but it’s expensive because of the hypervisor layer. On a 16GB RAM machine, we can barely run 3-4 VMs before machine becomes full.
Docker offers the best of both worlds:
- Running in isolation
- Running in a virtualized system
Each container’s processes are visible on the host.
Containers will run through container engines, such as Docker. They are platform that will offer a lot of tools to build/run/deploy containers and link components together. Docker is great at enabling finer-grained, microservice architecture
Docker Images contains:
- a minimal OS distribution
- dependencies
- a single application or service
Docker Images: Immutable Layers that build on top of each other. Docker registries are where you can push and pull your docker images
Takeaways
- Try to keep your Docker images small (e.g. base them on busybox, alpine, or debian base images)
- Don’t use Docker containers like full blown VMs - Run a single process/service in each Docker container
- Use Docker Networks as an alternative to legacy links for communicating between containers
- Consider using OS service scripts* (e.g. Upstart, Systemd) to manage your containers (e.g. pass environment variables, keep them running, start on boot and/or in a specific order)
