Helm包管理器

什么是Helm

Helm是Kubernetes的包管理器，用于定义、安装和升级复杂的Kubernetes应用。

核心概念

概念	说明
Chart	应用包，包含所有Kubernetes资源定义
Repository	Chart仓库
Release	Chart的运行实例
Values	配置参数

安装Helm

# macOS
brew install helm

# Linux
curl https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3 | bash

# 验证
helm version

常用命令

# 添加仓库
helm repo add bitnami https://charts.bitnami.com/bitnami
helm repo update

# 搜索Chart
helm search repo nginx

# 查看Chart信息
helm show chart bitnami/nginx
helm show values bitnami/nginx

# 安装Chart
helm install my-nginx bitnami/nginx

# 查看Release
helm list
helm status my-nginx

# 升级Release
helm upgrade my-nginx bitnami/nginx --set service.type=NodePort

# 卸载Release
helm uninstall my-nginx

创建Chart

初始化Chart

helm create mychart

Chart结构

mychart/
├── Chart.yaml          # Chart元数据
├── values.yaml         # 默认配置值
├── charts/             # 依赖的Chart
├── templates/          # 模板文件
│   ├── deployment.yaml
│   ├── service.yaml
│   ├── ingress.yaml
│   ├── _helpers.tpl
│   └── NOTES.txt
└── .helmignore

Chart.yaml

apiVersion: v2
name: mychart
description: My Helm chart
type: application
version: 0.1.0
appVersion: "1.0.0"
dependencies:
  - name: redis
    version: "17.x"
    repository: "https://charts.bitnami.com/bitnami"

values.yaml

replicaCount: 3

image:
  repository: myapp
  pullPolicy: IfNotPresent
  tag: "latest"

service:
  type: ClusterIP
  port: 80

ingress:
  enabled: true
  className: nginx
  hosts:
    - host: myapp.example.com
      paths:
        - path: /
          pathType: Prefix

resources:
  limits:
    cpu: 500m
    memory: 512Mi
  requests:
    cpu: 100m
    memory: 128Mi

模板语法

# templates/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ include "mychart.fullname" . }}
  labels:
    {{- include "mychart.labels" . | nindent 4 }}
spec:
  replicas: {{ .Values.replicaCount }}
  selector:
    matchLabels:
      {{- include "mychart.selectorLabels" . | nindent 6 }}
  template:
    metadata:
      labels:
        {{- include "mychart.selectorLabels" . | nindent 8 }}
    spec:
      containers:
        - name: {{ .Chart.Name }}
          image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
          imagePullPolicy: {{ .Values.image.pullPolicy }}
          ports:
            - containerPort: {{ .Values.service.port }}
          {{- if .Values.resources }}
          resources:
            {{- toYaml .Values.resources | nindent 12 }}
          {{- end }}

实践：部署应用

# 1. 创建Chart
helm create webapp

# 2. 修改配置
# 编辑 values.yaml 和模板文件

# 3. 打包Chart
helm package webapp

# 4. 安装
helm install my-webapp ./webapp \
    --set replicaCount=5 \
    --set image.tag=v2.0.0

# 5. 验证
kubectl get pods -l app.kubernetes.io/name=webapp
helm status my-webapp

Chart仓库管理

# 本地仓库
helm repo add local http://localhost:8080

# 推送Chart
cm-push mychart-0.1.0.tgz local

# 搜索Chart
helm search repo mychart

总结

Helm是Kubernetes应用管理的标准工具。通过Chart和Values，可以实现应用的可复用、可配置部署。