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This article mainly explains "what is the core function of Kubernetes". Interested friends may wish to take a look. The method introduced in this paper is simple, fast and practical. Now let the editor take you to learn "what is the core function of Kubernetes"?

Core functions of Kubernetes

The whole system consists of a master node and several working nodes. The developer submits a list of applications to the master node, and Kubemetes deploys them to the worker node of the cluster. It doesn't matter to developers and system administrators which node the component is deployed on.

Kubemetes can be treated as an operating system of a cluster, reducing the mental burden that developers have to implement infrastructure-related services in their applications. They now rely on Kubemetes to provide these services, including service discovery, expansion, load balancing, self-recovery, and even leadership elections. As a result, application developers can focus on implementing the functions of the application itself without wasting time thinking about how to integrate the application and infrastructure.

Kubernetes cluster architecture

At the hardware level, a Kubernetes cluster consists of many nodes, which are divided into two types, the master node, which carries the control panel for Kubernetes to control and manage the entire cluster system. The work nodes, on the other hand, run the applications actually deployed by the user.

Control panel

The control panel is used to control the cluster and make it work. It contains multiple components that can be run on a single primary node or deployed on multiple primary nodes through replicas to ensure high availability.

Kubernetes API server, you and other control panel components have to communicate with it; the key service process that provides HTTP Rest interface is the only entry for adding, deleting, modifying and querying all resources in Kubernetes, and it is also the cluster control entry process.

Scheculer, which dispatches your application (assigns a worker node to each deployable component of the application). Controller Manager, which performs cluster-level functions, such as copying components, continuously tracking work nodes, dealing with node failures, etc.; it is the automation control center of all resource objects in Kubernetes, which can be understood as the housekeeper of resource objects. Etcd, a reliable distributed data storage, can persist the cluster configuration; an etcd server process is often started on the Master node, because the data of all resource objects in the Kubernetes are stored in the etcd.

Basic concepts and terminology of Kubernetes

Most of the concepts in Kubernetes, such as Node, Pod, Replication Controller, Server, Deploymeng, Job, DaemonSet, etc., can be regarded as a kind of resource object. Almost all resource objects can be added, deleted, changed, looked up and stored in etcd through the kubectl tool provided by Kubernetes. From this point of view, Kubernets is actually a highly automated resource control system, which realizes the advanced functions of automatic control and automatic error correction by tracking and comparing the differences between the expected state of resources stored in etcd storage and the actual state of resources in the current environment. Pod: it is the most important and basic concept of kubernetes. Each Pod contains a "root container" and one or more closely connected business containers.

Kubernetes assigns a unique IP address to each Pod, called PodIP, and multiple containers in a Pod share PodIP addresses. The underlying network is required to support the direct communication between any two Pod in the cluster, which is usually implemented by virtual layer 2 network technology (Flannel).

At this point, I believe you have a deeper understanding of "what is the core function of Kubernetes". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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