第三章：Chart 开发

创建 Chart

# 创建 Chart
helm create mychart

# 查看结构
tree mychart/

Chart 结构详解

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
│   ├── serviceaccount.yaml
│   ├── configmap.yaml
│   ├── ingress.yaml
│   ├── hpa.yaml
│   ├── _helpers.tpl    # 模板助手
│   └── NOTES.txt       # 安装说明
├── .helmignore         # 打包忽略文件
└── LICENSE             # 许可证

Chart.yaml 配置

apiVersion: v2
name: mychart
description: A Helm chart for Kubernetes
type: application

# Chart 版本（SemVer 2）
version: 1.0.0

# 应用版本
appVersion: "1.0.0"

# Kubernetes 版本要求
kubeVersion: ">=1.20.0"

# 关键词
keywords:
  - web
  - nginx

# 主页
home: https://example.com

# 源码
sources:
  - https://github.com/user/mychart

# 维护者
maintainers:
  - name: Your Name
    email: your@email.com
    url: https://example.com

# 图标
icon: https://example.com/icon.png

# 注解
annotations:
  category: Infrastructure

# 依赖
dependencies:
  - name: redis
    version: "16.x.x"
    repository: "https://charts.bitnami.com/bitnami"
    condition: redis.enabled
    tags:
      - cache
    alias: redis

values.yaml 配置

# 默认配置值
replicaCount: 1

image:
  repository: nginx
  pullPolicy: IfNotPresent
  tag: ""

imagePullSecrets: []
nameOverride: ""
fullnameOverride: ""

serviceAccount:
  create: true
  annotations: {}
  name: ""

podAnnotations: {}
podSecurityContext: {}
  # fsGroup: 2000

securityContext: {}
  # capabilities:
  #   drop:
  #   - ALL
  # readOnlyRootFilesystem: true
  # runAsNonRoot: true
  # runAsUser: 1000

service:
  type: ClusterIP
  port: 80

ingress:
  enabled: false
  className: ""
  annotations: {}
  hosts:
    - host: chart-example.local
      paths:
        - path: /
          pathType: ImplementationSpecific
  tls: []

resources: {}
  # limits:
  #   cpu: 100m
  #   memory: 128Mi
  # requests:
  #   cpu: 100m
  #   memory: 128Mi

autoscaling:
  enabled: false
  minReplicas: 1
  maxReplicas: 100
  targetCPUUtilizationPercentage: 80

nodeSelector: {}
tolerations: []
affinity: {}

模板文件

deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ include "mychart.fullname" . }}
  labels:
    {{- include "mychart.labels" . | nindent 4 }}
spec:
  {{- if not .Values.autoscaling.enabled }}
  replicas: {{ .Values.replicaCount }}
  {{- end }}
  selector:
    matchLabels:
      {{- include "mychart.selectorLabels" . | nindent 6 }}
  template:
    metadata:
      annotations:
        checksum/config: {{ include (print $.Template.BasePath "/configmap.yaml") . | sha256sum }}
      {{- with .Values.podAnnotations }}
        {{- toYaml . | nindent 8 }}
      {{- end }}
      labels:
        {{- include "mychart.selectorLabels" . | nindent 8 }}
    spec:
      {{- with .Values.imagePullSecrets }}
      imagePullSecrets:
        {{- toYaml . | nindent 8 }}
      {{- end }}
      serviceAccountName: {{ include "mychart.serviceAccountName" . }}
      securityContext:
        {{- toYaml .Values.podSecurityContext | nindent 8 }}
      containers:
        - name: {{ .Chart.Name }}
          securityContext:
            {{- toYaml .Values.securityContext | nindent 12 }}
          image: "{{ .Values.image.repository }}:{{ .Values.image.tag | default .Chart.AppVersion }}"
          imagePullPolicy: {{ .Values.image.pullPolicy }}
          ports:
            - name: http
              containerPort: {{ .Values.service.port }}
              protocol: TCP
          {{- if .Values.livenessProbe.enabled }}
          livenessProbe:
            httpGet:
              path: {{ .Values.livenessProbe.path }}
              port: http
            initialDelaySeconds: {{ .Values.livenessProbe.initialDelaySeconds }}
            periodSeconds: {{ .Values.livenessProbe.periodSeconds }}
          {{- end }}
          {{- if .Values.readinessProbe.enabled }}
          readinessProbe:
            httpGet:
              path: {{ .Values.readinessProbe.path }}
              port: http
            initialDelaySeconds: {{ .Values.readinessProbe.initialDelaySeconds }}
            periodSeconds: {{ .Values.readinessProbe.periodSeconds }}
          {{- end }}
          resources:
            {{- toYaml .Values.resources | nindent 12 }}
          {{- if .Values.env }}
          env:
            {{- toYaml .Values.env | nindent 12 }}
          {{- end }}
          {{- if .Values.config.enabled }}
          volumeMounts:
            - name: config
              mountPath: /etc/config
          {{- end }}
      {{- if .Values.config.enabled }}
      volumes:
        - name: config
          configMap:
            name: {{ include "mychart.fullname" . }}
      {{- end }}
      {{- with .Values.nodeSelector }}
      nodeSelector:
        {{- toYaml . | nindent 8 }}
      {{- end }}
      {{- with .Values.affinity }}
      affinity:
        {{- toYaml . | nindent 8 }}
      {{- end }}
      {{- with .Values.tolerations }}
      tolerations:
        {{- toYaml . | nindent 8 }}
      {{- end }}

service.yaml

apiVersion: v1
kind: Service
metadata:
  name: {{ include "mychart.fullname" . }}
  labels:
    {{- include "mychart.labels" . | nindent 4 }}
spec:
  type: {{ .Values.service.type }}
  ports:
    - port: {{ .Values.service.port }}
      targetPort: http
      protocol: TCP
      name: http
  selector:
    {{- include "mychart.selectorLabels" . | nindent 4 }}

ingress.yaml

{{- if .Values.ingress.enabled -}}
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: {{ include "mychart.fullname" . }}
  labels:
    {{- include "mychart.labels" . | nindent 4 }}
  {{- with .Values.ingress.annotations }}
  annotations:
    {{- toYaml . | nindent 4 }}
  {{- end }}
spec:
  {{- if .Values.ingress.className }}
  ingressClassName: {{ .Values.ingress.className }}
  {{- end }}
  {{- if .Values.ingress.tls }}
  tls:
    {{- range .Values.ingress.tls }}
    - hosts:
        {{- range .hosts }}
        - {{ . | quote }}
        {{- end }}
      secretName: {{ .secretName }}
    {{- end }}
  {{- end }}
  rules:
    {{- range .Values.ingress.hosts }}
    - host: {{ .host | quote }}
      http:
        paths:
          {{- range .paths }}
          - path: {{ .path }}
            pathType: {{ .pathType }}
            backend:
              service:
                name: {{ include "mychart.fullname" $ }}
                port:
                  number: {{ $.Values.service.port }}
          {{- end }}
    {{- end }}
{{- end }}

configmap.yaml

{{- if .Values.config.enabled -}}
apiVersion: v1
kind: ConfigMap
metadata:
  name: {{ include "mychart.fullname" . }}
  labels:
    {{- include "mychart.labels" . | nindent 4 }}
data:
  {{- range $key, $value := .Values.config.data }}
  {{ $key }}: {{ $value | quote }}
  {{- end }}
{{- end }}

_helpers.tpl

{{/*
Expand the name of the chart.
*/}}
{{- define "mychart.name" -}}
{{- default .Chart.Name .Values.nameOverride | trunc 63 | trimSuffix "-" }}
{{- end }}

{{/*
Create a default fully qualified app name.
*/}}
{{- define "mychart.fullname" -}}
{{- if .Values.fullnameOverride }}
{{- .Values.fullnameOverride | trunc 63 | trimSuffix "-" }}
{{- else }}
{{- $name := default .Chart.Name .Values.nameOverride }}
{{- if contains $name .Release.Name }}
{{- .Release.Name | trunc 63 | trimSuffix "-" }}
{{- else }}
{{- printf "%s-%s" .Release.Name $name | trunc 63 | trimSuffix "-" }}
{{- end }}
{{- end }}
{{- end }}

{{/*
Create chart name and version as used by the chart label.
*/}}
{{- define "mychart.chart" -}}
{{- printf "%s-%s" .Chart.Name .Chart.Version | replace "+" "_" | trunc 63 | trimSuffix "-" }}
{{- end }}

{{/*
Common labels
*/}}
{{- define "mychart.labels" -}}
helm.sh/chart: {{ include "mychart.chart" . }}
{{ include "mychart.selectorLabels" . }}
{{- if .Chart.AppVersion }}
app.kubernetes.io/version: {{ .Chart.AppVersion | quote }}
{{- end }}
app.kubernetes.io/managed-by: {{ .Release.Service }}
{{- end }}

{{/*
Selector labels
*/}}
{{- define "mychart.selectorLabels" -}}
app.kubernetes.io/name: {{ include "mychart.name" . }}
app.kubernetes.io/instance: {{ .Release.Name }}
{{- end }}

{{/*
Create the name of the service account to use
*/}}
{{- define "mychart.serviceAccountName" -}}
{{- if .Values.serviceAccount.create }}
{{- default (include "mychart.fullname" .) .Values.serviceAccount.name }}
{{- else }}
{{- default "default" .Values.serviceAccount.name }}
{{- end }}
{{- end }}

依赖管理

Chart.yaml 中定义依赖

dependencies:
  - name: redis
    version: "16.x.x"
    repository: "https://charts.bitnami.com/bitnami"
    condition: redis.enabled
    tags:
      - cache
    alias: redis

  - name: postgresql
    version: "12.x.x"
    repository: "https://charts.bitnami.com/bitnami"
    condition: postgresql.enabled

管理依赖

# 下载依赖
helm dependency update mychart

# 查看依赖
helm dependency list mychart

# 构建依赖
helm dependency build mychart

Chart 测试

测试文件

# templates/tests/test-connection.yaml
apiVersion: v1
kind: Pod
metadata:
  name: "{{ include "mychart.fullname" . }}-test-connection"
  labels:
    {{- include "mychart.labels" . | nindent 4 }}
  annotations:
    "helm.sh/hook": test
spec:
  containers:
    - name: wget
      image: busybox
      command: ['wget']
      args: ['{{ include "mychart.fullname" . }}:{{ .Values.service.port }}']
  restartPolicy: Never

运行测试

# 安装后测试
helm test myrelease

# 详细输出
helm test myrelease --logs

Chart 验证

# 语法检查
helm lint mychart

# 详细检查
helm lint mychart --strict

# 模板验证
helm template myrelease mychart | kubeval -

# 安全检查
helm template myrelease mychart | kubesec scan -

打包发布

# 打包
helm package mychart

# 打包并签名
helm package mychart --sign --key 'John Doe' --keyring ~/.gnupg/pubring.gpg

# 验证签名
helm verify mychart-1.0.0.tgz

小结

本章学习了：

• ✅ Chart 创建和结构
• ✅ Chart.yaml 配置
• ✅ values.yaml 配置
• ✅ 模板文件编写
• ✅ 依赖管理
• ✅ Chart 测试和验证

下一章

第四章：Chart 模板 - 深入学习模板语法。