Feature

![[images/24a08702-ae93-4466-83d7-1520ebc1f938.png]]

Kubernetes is an open-source system for automating deployment scaling, and management of containerized applications.

Kubernetes 提供了一个可弹性运行分布式系统的框架

  • Service Discovery / Load Balancing
  • Storage Orchestration
  • Automate Rollouts / Rollbacks
  • Self-healing
  • Secret and Configuration Management
  • Horizontal Scaling

Infrastructure

$$\text{K8S Cluster} = N\ \text{Master Nodes} + N\ \text{Worker Nodes} (N\geq1)$$

![[images/截屏2026-03-18 15.52.44.png]]

Pods and Containers

![[images/截屏2026-03-18 15.54.21.png]]

  • 一个 Pod 中可有多个 Container
  • 一个 Node 中也可有多个 Pod

Building Blocks

![[images/截屏2026-03-27 14.12.52.png]]

  • Service: Pod 和外界、和 Pod 之间进行交流
  • Deployment: 部署

Communicating with kubectl

![[images/截屏2026-03-18 16.09.01.png]]

  • Store (etcd): 存储主节点所需的信息（K-V 形式）
  • Controller Manager: 处理请求，并使用 Scheduler 进行任务调度
  • Scheduler: 任务调度，控制 Nodes 或 Pods 的运行
  • API Server: A RESTful server. 接收由 kubectl 提供的命令并转发给 Controller Manager 执行

![[images/image.png]]

Node

![[images/截屏2026-03-18 16.16.15.png]]

  • Kubelet: Agent running on each node. 该代理向集群注册该节点并与管理器来回通信
  • Container Runtime: Run containers within the pods
  • Kube-Proxy: 为每个 Pod 提供唯一 IP 地址，并与服务进行绑定

Use Cases

  • Emulate production locally
  • Move from Docker Compose to Kubernetes
  • Create an end-to-end test environment
  • Ensure application scales properly
  • Ensure secrets/config are working properly
  • Performance testing scenarios
  • Workload scenarios (CI/CD …)
  • Learn how to leverage deployment options
  • Help DevOps create resources and solve problems

Ways to Deploy

  1. minikube
  2. Docker Desktop
  3. kubeadm
  4. kind

kubectl

Command Function
kubectl version Check version
kubectl cluster-info View cluster information
kubectl get all Retrieve information about Kubernetes Pods, Deployments, Services, and more
kubectl get pods Get only pods
kubectl run [container-name] --image=[image-name] Simple way to create a Deployment for a Pod
kubectl port-forward [pod] [ports] Forward a port to allow external
kubectl expose Expose a port for a Deployment/Pod
kubectl create [resource] Create a resource
kubectl apply [resource] Create or modify a resource

可以为 kubectl 设置别名

Windows:

Set-Alias -Name k -Value kubectl

Mac/Linux

alias k="kubectl"

Web UI Dashboard (Mac)

旧版原生 Dashboard 已经弃用，现使用 Headlamp

安装后即可直接查看本地运行的 cluster

Troubleshoot

Log

# View the logs for a Pod's container
kubectl logs [pod_name]
# View the logs for a specific container within a Pod
kubectl logs [pod_name] -c [container_name]
# View the logs for a previously running Pod
kubectl logs -p [pod_name]
# Stream a Pod's logs
kubectl logs -f [pod_name]
# Watch a resource
kubectl get [pod_name] --watch

Describe

# Describe a Pod
kubectl describe pod [pod_name]
# Change a Pod's output format
kubectl get pod [pod_name] -o yaml
# Change a Deployment's output format
kubectl get deployment [deployment_name] -o yaml

Shell Into

kubectl exec -it [pod-name] -- sh