74 lines
3.5 KiB
Markdown
74 lines
3.5 KiB
Markdown
---
|
|
description: Explains what the Registry is, basic use cases and requirements
|
|
keywords: registry, on-prem, images, tags, repository, distribution, use cases, requirements
|
|
title: About Registry
|
|
---
|
|
|
|
A registry is a storage and content delivery system, holding named container
|
|
images and other content, available in different tagged versions.
|
|
|
|
> Example: the image `distribution/registry`, with tags `2.0` and `2.1`.
|
|
|
|
Users interact with a registry by pushing and pulling images.
|
|
|
|
> Example: `docker pull registry-1.docker.io/distribution/registry:2.1`.
|
|
|
|
Storage itself is delegated to drivers. The default storage driver is the local
|
|
posix filesystem, which is suitable for development or small deployments.
|
|
Additional cloud-based storage drivers like S3, Microsoft Azure and Google Cloud Storage
|
|
are supported. People looking into using other storage drivers should consider if
|
|
the driver they'd like to be supported is S3 compatible like many cloud storage systems
|
|
as adding new storage driver support has been put on hold for the time being.
|
|
|
|
Since securing access to your hosted images is paramount, the Registry natively
|
|
supports TLS and basic authentication.
|
|
|
|
The Registry GitHub repository includes additional information about advanced
|
|
authentication and authorization methods. Only very large or public deployments
|
|
are expected to extend the Registry in this way.
|
|
|
|
Finally, the Registry ships with a robust [notification system](notifications),
|
|
calling webhooks in response to activity, and both extensive logging and reporting,
|
|
mostly useful for large installations that want to collect metrics.
|
|
|
|
## Understanding image naming
|
|
|
|
Image names as used in typical docker commands reflect their origin:
|
|
|
|
* `docker pull ubuntu` instructs docker to pull an image named `ubuntu` from Docker Hub. This is simply a shortcut for the longer `docker pull docker.io/library/ubuntu` command
|
|
* `docker pull myregistrydomain:port/foo/bar` instructs docker to contact the registry located at `myregistrydomain:port` to find the image `foo/bar`
|
|
|
|
You can find out more about the various Docker commands dealing with images in
|
|
the [Docker engine documentation](https://docs.docker.com/engine/reference/commandline/cli/).
|
|
|
|
## Use cases
|
|
|
|
Running your own Registry is a great solution to integrate with and complement
|
|
your CI/CD system. In a typical workflow, a commit to your source revision
|
|
control system would trigger a build on your CI system, which would then push a
|
|
new image to your Registry if the build is successful. A notification from the
|
|
Registry would then trigger a deployment on a staging environment, or notify
|
|
other systems that a new image is available.
|
|
|
|
It's also an essential component if you want to quickly deploy a new image over
|
|
a large cluster of machines.
|
|
|
|
Finally, it's the best way to distribute images inside an isolated network.
|
|
|
|
## Requirements
|
|
|
|
You absolutely need to be familiar with Docker, specifically with regard to
|
|
pushing and pulling images. You must understand the difference between the
|
|
daemon and the cli, and at least grasp basic concepts about networking.
|
|
|
|
Also, while just starting a registry is fairly easy, operating it in a
|
|
production environment requires operational skills, just like any other service.
|
|
You are expected to be familiar with systems availability and scalability,
|
|
logging and log processing, systems monitoring, and security 101. Strong
|
|
understanding of http and overall network communications, plus familiarity with
|
|
golang are certainly useful as well for advanced operations or hacking.
|
|
|
|
## Next
|
|
|
|
Dive into [deploying your registry](deploying)
|