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This article will explain in detail what the kubernetes architecture design is like. The editor thinks it is very practical, so I share it with you for reference. I hope you can get something after reading this article.

Kubernetes cluster contains node agent kubelet and master components (APIs, Scheduler, ect.). Everything is based on a distributed storage system.

2. Kubernetes cluster architecture diagram:

Parsing:

1. In this system architecture diagram, services are divided into services running on work nodes and services that make up cluster-level dashboards.

The 2.kubernetes node has the services necessary to run the application container, all of which are controlled by master.

3.docker is the basis for each node to run, and docker is responsible for downloading all specific images and running the container.

4.kubernetes mainly consists of the following core components:

A.etcd saves the state of the entire cluster

B.apiserver provides a unique entry for resource operations and provides mechanisms such as authentication, authorization, access control, API registration and discovery.

C.controller manager is responsible for maintaining the status of the cluster, such as fault detection, automatic extension, rolling updates, etc.

D.scheduler is responsible for resource scheduling and dispatches Pod to the corresponding machines according to the predetermined scheduling policy.

E.kubelet is responsible for maintaining the life cycle of the container, as well as the management of Volume (CVI) and network (CNI).

F.Container runtime is responsible for image management and the actual operation of Pod and containers.

G.kube-proxy is responsible for providing Service with service discovery and load balancing within cluster.

Recommended add-ons for 5.kubernetes:

A.kube-dns is responsible for providing DNS services for the entire cluster.

B.Ingress-controller provides public network access for services.

C.Heapter provides resource monitoring

D.Dashboard provides GUI

E.Federation provides clusters across availability zones

F.Fluentd-elasticsearch provides cluster log collection, storage and query.

III. Hierarchical architecture

The design concept and function of kubernetes is actually a hierarchical architecture similar to linux, as shown in the following figure:

1. Core layer: the core function of kubernetes, which provides API to build high-level applications and plug-in application execution environment internally.

two。 Application layer: deployment (stateless applications, stateful applications, batch tasks, cluster applications, etc.) and routing (service discovery, DNS parsing, etc.).

3. Management: system metrics (such as infrastructure, container, and network metrics), automation (such as automatic extension, dynamic provision, etc.), and policy management (RBAC, Quota, PSP, Network policy etc.).

4. Interface layer: kubelet command line tools, client SDK, cluster.

5. Ecosystem: a large container cluster above the interface layer manages and dispatches the ecosystem, which can be divided into two categories:

External to a.kubenetes: logging, monitoring, configuration management, CI, CD, Workflow, FaaS, OTS applications, ChatOps, etc.

B.kubenetes internal: CRI, CNI, CVI, image repository, Cloud Provider, configuration and management of cluster itself, etc.

IV. Kubelet

Kubelet is responsible for managing Pods and its containers, images images, volumes, etc.

5. Kube-proxy

Each node also runs a simple network agent and load balancing. Service endpoints are currently resolved through DNS or environment variables, which are resolved using ports managed by the service broker.

VI. Kubenetes control panel

The kubenetes control panel can be divided into multiple parts. Currently they all run on a master node, which needs to be changed in order to achieve high availability, with different parts working together to provide a unified view of the cluster.

7. Etcd

The persistent state of all master exists in an instance of etcd. This is a good way to store configuration data. Because of the support of watch, changes in the coordination of various components can be detected quickly.

VIII. Kubernetes API Server

The API service provides services for Kubernetes API. This service attempts to make it CRUD by putting all or most of the business logic into more than two parts. It mainly deals with REST operations, validating updates to these objects in etcd and eventually storing them.

IX. Scheduler

The scheduler binds the unscheduled pod to the node through binding api. The scheduler is pluggable and supports multi-cluster scheduling, and may support user-defined schedulers in the future.

10. Kubenetes control and management server

All other cluster-level functions are currently the responsibility of the control manager. For example, the endpoint object is updated by the endpoint controller. These can eventually be divided into different parts to make them pluggable on their own.

Replication controller is a mechanism based on simple podAPI. It will eventually become a universal plug-in mechanism.

This is the end of this article on "what is the design of kubernetes architecture?". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, please share it for more people to see.

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