Image namespaces

So far, you have been pulling various images and haven't worried so much about where those images originated from. Your Docker environment is configured so that, by default, all images are pulled from Docker Hub. We also only pulled so-called official images from the Docker Hub, such as alpine or busybox.

Now it is time to widen our horizon a bit and learn about how images are namespaced. The most generic way to define an image is by its fully qualified name, which looks as follows:

<registry URL>/<User or Org>/<name>:<tag>

Let's look at this in a bit more detail:

  •  <registry URL>: This is the URL to the registry from which we want to pull the image. By default, this is docker.io. More generally, this could be https://registry.acme.com ...

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