Chapter3.md

Chapter 3 - Docker Hub

The Power Of Community

Part of the power of Docker is the ecosystem that drives it.

Standing on the shoulders of giants, Isaac Newton

Whether you're working in Java, Node.js, .Net or any other language, there'll be containers that do most of the hard work for you.

We'll be using a Node image later on as an example of how you this works.

Your Local Image Cache

Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world

Whenever you build an image or pull one from a repository it is stored locally on your machine. Then, naturally, this cache is queried on all commands. This is where a lot of the speed of Docker comes from.

Because we're storing everything, all the time, this can start to take up significant amounts of room. There's a couple of convenience commands that will prove useful. We'll revisit them in the next chapter as they have other uses.

Command	Definition
docker container prune	Removes all the stopped containers
docker image prune	Removes all the images not required by containers

Searching Docker Hub

The biggest and default repository of Docker Images is at https://hub.docker.com/

Go there now and see what you can find for your favourite ecosystem.