I believe that many beginners will be very confused about the concept of registry in K8s (Kubernetes), because it is really difficult to translate into Chinese, and the literal translation of "registration" is very confusing. There are very few Chinese materials on the Internet in this regard.
1 registry in windows
First of all, it can be understood from an approximate concept: that is, the registry in the windows system, which also uses this word, registry.
The definition of the windows registry on Wiki:
The Windows Registry (Registry Editor or regedit.exe) is a hierarchical database that stores low-level settings for the Microsoft Windows operating system and for applications that opt to use the registry.
The kernel, device drivers, services, Security Accounts Manager, and user interfaces can all use the registry. The registry also allows access to counters for profiling system performance.
In other words, the registry or Windows Registry contains information, settings, options, and other values for programs and hardware installed on all versions of Microsoft Windows operating systems. For example, when a program is installed, a new subkey containing settings such as a program’s location, its version, and how to start the program, are all added to the Windows Registry.
Focus on translating these two bold words:
The Windows Registry (Registry Editor or regedit.exe) is a hierarchical database used to store the underlying settings of the Microsoft Windows operating system and applications that choose to use the registry.
In other words, the Registry, or Windows Registry, contains information, settings, options, and other values for programs and hardware installed on all versions of the Microsoft Windows operating system.
2. registry in k8s
There are at least three types of registries, Kubernetes Registry, Docker Registry and container registry. The following will explain these registries.
The explanation of the following two concepts is based on reference materials
A Docker registry contains Docker images that you can pull in order to use them in your deployment. The registry is a stateless, scalable server side application that stores and lets you distribute Docker images.
The Docker registry contains Docker images that you can use in your deployments. Registry is a stateless, scalable server-side application for storing and distributing Docker images.
The Kubernetes registry is an image pull secret that your deployment uses to authenticate with a Docker registry.
The Kubernetes registry is a mirror pull secret (see what is a secret: kubernetes design concept , deployment is a layer in the pod) use it to authenticate with the Docker registry.
The following is the content in Reference 2.
A container registry is a repository—or collection of repositories—used to store and access container images.
A container registry is a repository (or collection of repositories) for storing and accessing container images. This is the one we see most in docker. Container registry is also called image registry. The introduction of image in the k8s official document also includes the concepts of private registry and public registry, indicating that the registry here means nothing but collection.
3. Summary
Registry has different meanings in different scenarios. For k8s, it is very simple, it means storage warehouse . In other scenarios (such as Windows, it may also contain some configuration information. If there are other meanings, please leave a message to communicate~~