Kubernetes（k8s）: A container orchestration system open sourced by Google.
Origin of the name: Kubernetes is a long word, and the middle 8 letters are usually omitted, abbreviated as k8s.
It sits between application services and servers, coordinating and managing multiple application services through policies.
Through YAML file configuration, automatic deployment, automatic restart, and automatic expansion and contraction of applications can be achieved.
Kubernetes Architecture
Control Plane: It is equivalent to the brain of the cluster, responsible for managing and controlling working nodes.
Components include:
API Server: Provides an API interface for operating service resources.
Scheduler: Responsible for resource scheduling decisions.
Controller Manager: Responsible for the creation and closing of application services.
etcd: As the storage layer, it saves cluster status and data.
Worker Node: It is equivalent to the hands and feet of the cluster, responsible for executing tasks and running application services.
Components include:
Pod: A running instance of a container, the smallest scheduling unit in k8s.
Kubelet: Responsible for the lifecycle management of Pod.
Container Runtime: Responsible for the lifecycle management of containers, such as Docker.
Kube Proxy: Responsible for Node's network proxy and request forwarding.
Kubernetes Core Concepts
Cluster: Consists of a control plane and multiple working nodes.
Container Image: A packaged file containing application code and dependent environments.
Container: The running unit of the application service.
Pod: A collection of one or more containers that share network and storage resources.
Kubernetes Operations Tools
kubectl: A command line tool provided by k8s, used to interact with the k8s API to simplify service deployment and management.
Service deployment and calling process
Deployment Service: Deploy services by writing YAML files and executing kubectl commands.
Service Call: External requests enter the cluster through the Ingress controller and are forwarded to the corresponding Pod by Kube Proxy.
Kubernetes Advantages
Automatic deployment, restart, and scaling.
Simplify the deployment and operation and maintenance process of services.
Supports the management of large-scale container services.
Summarize
k8s is a powerful container orchestration tool that realizes the automated management and scheduling of application services through the collaboration of the control plane and worker nodes.
The control plane is responsible for decision-making and issuing instructions, while the working nodes are responsible for executing tasks and running applications.
Through the kubectl tool, users can easily interact with the k8s API to achieve rapid deployment and management of services.
