6 Containers in action
This chapter covers
- Using GitHub Actions to build and push containers
- Attaching storage volumes and maintaining state
- Using file-based environment variables
- Running and managing multiple containers with Docker Compose
- Learning container-to-container networking and communication basics
Imagine sitting in an audience where CodeOprah comes out and says, “You get a container and you get a container and you get a container—everyone gets a container!” The crowd goes wild. But you don’t—not yet, anyway. You’re sitting there asking yourself a few fundamental questions. How do I run a database within a container? How do my two containers talk to each other? How do I manage multiple containers at once? Before we start passing out containers like they’re free cars, we need to configure our end-to-end CI/CD pipeline to allow GitHub Actions to be responsible for building and pushing our containers to Docker Hub.
Once our build process is automated, we need to understand how to inject state into containers by using volumes. Volumes are a way to persist data directly in a container regardless of the current status or state of the container. They can exist even if the container is not running or completely destroyed. Using volumes is how we get stateful, or the opposite of stateless, containers.