So Docker. Docker. Everyone’s talking about Docker a lot. Everyone says Docker is important. So what does one do about all this Docker? Well, I started reading the documentation because I have only a vague idea of what it is supposed to do.
My initial thoughts on reading the overview:
- Seems very similar to Python virtual environments but not restricted to just Python.
- I have a suspicion that I could develop and deploy my apps for work easier with this.
- There’s a lot to learn and a lot of definitions to keep straight and remember.
For my own benefit, I’m going to outline here some key definitions from my reading. Usually writing something down helps me remember it and solidify the concepts.
Docker consists basically of images that you use to make containers which allows you to have a lot more flexibility with moving around and editing and deploying applications. Below are some basic definitions are each, which I found helpful to have outlined a bit more succinctly than their wordier explanations in the official documentation.
Docker Images
- Read only template
- Generally base it on one image and then customize your own image to suit your needs
- Defined in a Dockerfile
- Like onions and ogres, Dockerfiles have layers. Unlike ogres, Dockerfiles define the layers with instructions.
- Only changed layers are rebuilt when the image is rebuilt
- The image provides the filesystem
Docker Containers
- TL;DR a container is an encapsulated running process with it’s own filesystem
- A runnable image instance
- Define your container with its image and your configuration options
- Isolated from everything else and you get to control networking, storage, etc on it.
- Uses namespaces for each container and container isolation
- Use control groups to limit an application’s resources
Docker Services
- Swarm = scale containers across multiple Docker daemons
- Daemons communicate through the Docker API
- Lets you define the state for your swarm.
Well, there’s the very basic gist from my reading. I was able to get Docker desktop successfully installed and running no problems with their documentation. More later.
-Rachel
Rachel Geist 