Helm 차트: Kubernetes 패키지 관리

my-app-chart/
├── Chart.yaml          # Chart 메타데이터 및 버전
├── values.yaml         # 기본 구성 값
├── charts/             # 종속 Chart
├── templates/          # Kubernetes 리소스 템플릿
│   ├── deployment.yaml
│   ├── service.yaml
│   ├── ingress.yaml
│   ├── _helpers.tpl    # 템플릿 도우미
│   └── NOTES.txt       # 설치 후 메모
├── .helmignore         # 패키징 시 무시할 파일
├── README.md
└── LICENSE

helm create my-application
cd my-application

apiVersion: v2
name: my-application
description: A production-ready application chart
type: application
version: 1.0.0        # Chart 버전
appVersion: "2.4.1"   # 애플리케이션 버전

maintainers:
  - name: Your Team
    email: team@company.com

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

replicaCount: 3

image:
  repository: myapp/backend
  tag: "1.0.0"
  pullPolicy: IfNotPresent

service:
  type: ClusterIP
  port: 80

ingress:
  enabled: true
  className: "nginx"
  annotations:
    cert-manager.io/cluster-issuer: "letsencrypt-prod"
  hosts:
    - host: myapp.example.com
      paths:
        - path: /
          pathType: Prefix

resources:
  limits:
    cpu: 500m
    memory: 512Mi
  requests:
    cpu: 250m
    memory: 256Mi

autoscaling:
  enabled: true
  minReplicas: 3
  maxReplicas: 10
  targetCPUUtilizationPercentage: 80

apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ include "my-application.fullname" . }}
  labels:
    {{- include "my-application.labels" . | nindent 4 }}
spec:
  {{- if not .Values.autoscaling.enabled }}
  replicas: {{ .Values.replicaCount }}
  {{- end }}
  selector:
    matchLabels:
      {{- include "my-application.selectorLabels" . | nindent 6 }}
  template:
    metadata:
      labels:
        {{- include "my-application.selectorLabels" . | nindent 8 }}
    spec:
      containers:
      - name: {{ .Chart.Name }}
        image: "{{ .Values.image.repository }}:{{ .Values.image.tag | default .Chart.AppVersion }}"
        imagePullPolicy: {{ .Values.image.pullPolicy }}
        ports:
        - containerPort: 8080
          protocol: TCP
        resources:
          {{- toYaml .Values.resources | nindent 10 }}

{{/*
차트 이름을 확장합니다.
*/}}
{{- define "my-application.name" -}}
{{- default .Chart.Name .Values.nameOverride | trunc 63 | trimSuffix "-" }}
{{- end }}

{{/*
기본적으로 완전한 애플리케이션 이름을 생성합니다.
*/}}
{{- define "my-application.fullname" -}}
{{- if .Values.fullnameOverride }}
{{- .Values.fullnameOverride | trunc 63 | trimSuffix "-" }}
{{- else }}
{{- $name := default .Chart.Name .Values.nameOverride }}
{{- printf "%s-%s" .Release.Name $name | trunc 63 | trimSuffix "-" }}
{{- end }}
{{- end }}

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

# 리포지토리에서 설치
helm install my-release bitnami/postgresql

# 로컬 디렉토리에서 설치
helm install my-app ./my-application

# 사용자 정의 값으로 설치
helm install my-app ./my-application -f values-production.yaml

# 인라인 값 오버라이드로 설치
helm install my-app ./my-application \
  --set replicaCount=5 \
  --set image.tag=2.0.0

# 새 값으로 업그레이드
helm upgrade my-app ./my-application -f values-production.yaml

# 실패 시 자동 롤백
helm upgrade my-app ./my-application --atomic --timeout 5m

# 리소스 강제 업데이트
helm upgrade my-app ./my-application --force

# 릴리스 이력 보기
helm history my-app

# 이전 버전으로 롤백
helm rollback my-app

# 특정 버전으로 롤백
helm rollback my-app 3

# 생성된 매니페스트를 보기 위한 드라이런
helm install my-app ./my-application --dry-run --debug

# 설치 없이 템플릿 렌더링
helm template my-app ./my-application

# 차트 문제점 검사
helm lint ./my-application

# 테스트 훅으로 릴리스 테스트
helm test my-app

dependencies:
  - name: redis
    version: "17.x.x"
    repository: "https://charts.bitnami.com/bitnami"
    condition: redis.enabled
  - name: postgresql
    version: "12.x.x"
    repository: "https://charts.bitnami.com/bitnami"
    condition: postgresql.enabled

helm dependency update ./my-application

apiVersion: batch/v1
kind: Job
metadata:
  name: {{ include "my-application.fullname" . }}-db-migration
  annotations:
    "helm.sh/hook": pre-upgrade,pre-install
    "helm.sh/hook-weight": "5"
    "helm.sh/hook-delete-policy": before-hook-creation
spec:
  template:
    spec:
      containers:
      - name: db-migrate
        image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
        command: ["python", "manage.py", "migrate"]
      restartPolicy: Never

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

# 레지스트리 로그인
helm registry login registry.example.com

# 차트 패키징
helm package ./my-application

# OCI 레지스트리에 푸시
helm push my-application-1.0.0.tgz oci://registry.example.com/charts

# OCI 레지스트리에서 설치
helm install my-app oci://registry.example.com/charts/my-application --version 1.0.0

# -- 애플리케이션 복제 수
replicaCount: 3

# -- 이미지 구성
image:
  # -- 이미지 저장소
  repository: myapp/backend
  # -- 이미지 끌어오기 정책
  pullPolicy: IfNotPresent
  # -- 이미지 태그 (기본값은 chart appVersion)
  tag: ""

resources:
  limits:
    cpu: 1000m
    memory: 1Gi
  requests:
    cpu: 500m
    memory: 512Mi

securityContext:
  runAsNonRoot: true
  runAsUser: 1000
  fsGroup: 1000
  capabilities:
    drop:
    - ALL
  readOnlyRootFilesystem: true

livenessProbe:
  httpGet:
    path: /health
    port: 8080
  initialDelaySeconds: 30
  periodSeconds: 10

readinessProbe:
  httpGet:
    path: /ready
    port: 8080
  initialDelaySeconds: 5
  periodSeconds: 5

envFrom:
- secretRef:
    name: {{ include "my-application.fullname" . }}-secrets
- configMapRef:
    name: {{ include "my-application.fullname" . }}-config

{
  "$schema": "https://json-schema.org/draft-07/schema#",
  "properties": {
    "replicaCount": {
      "type": "integer",
      "minimum": 1
    },
    "image": {
      "type": "object",
      "properties": {
        "repository": {
          "type": "string"
        },
        "tag": {
          "type": "string"
        }
      },
      "required": ["repository"]
    }
  },
  "required": ["image"]
}

1. 애플리케이션 URL을 얻으려면 다음을 실행하세요:
{{- if .Values.ingress.enabled }}
  https://{{ (index .Values.ingress.hosts 0).host }}
{{- else if contains "NodePort" .Values.service.type }}
  export NODE_PORT=$(kubectl get --namespace {{ .Release.Namespace }} -o jsonpath="{.spec.ports[0].nodePort}" services {{ include "my-application.fullname" . }})
  export NODE_IP=$(kubectl get nodes --namespace {{ .Release.Namespace }} -o jsonpath="{.items[0].status.addresses[0].address}")
  echo http://$NODE_IP:$NODE_PORT
{{- end }}

2. 배포를 모니터링하세요:
  kubectl --namespace {{ .Release.Namespace }} get pods -l "app.kubernetes.io/name={{ include "my-application.name" . }}"

# chart-testing 설치
brew install chart-testing

# 차트 린트
ct lint --config ct.yaml

# 차트 설치 및 테스트
ct install --config ct.yaml

name: Helm Chart CI

on:
  push:
    branches: [main]
  pull_request:
    branches: [main]

jobs:
  lint-test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
        with:
          fetch-depth: 0

      - name: Helm 설정
        uses: azure/setup-helm@v3
        with:
          version: 3.12.0

      - name: chart-testing 설정
        uses: helm/chart-testing-action@v2

      - name: 차트 린트
        run: ct lint --config ct.yaml

      - name: kind 클러스터 생성
        uses: helm/kind-action@v1

      - name: 차트 설치
        run: ct install --config ct.yaml

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: my-application
  namespace: argocd
spec:
  project: default
  source:
    repoURL: https://github.com/myorg/my-app-chart
    targetRevision: main
    path: charts/my-application
    helm:
      valueFiles:
        - values-production.yaml
  destination:
    server: https://kubernetes.default.svc
    namespace: production
  syncPolicy:
    automated:
      prune: true
      selfHeal: true

apiVersion: helm.toolkit.fluxcd.io/v2beta1
kind: HelmRelease
metadata:
  name: my-application
  namespace: flux-system
spec:
  interval: 5m
  chart:
    spec:
      chart: my-application
      version: '1.x.x'
      sourceRef:
        kind: HelmRepository
        name: my-charts
  values:
    replicaCount: 5
    image:
      tag: "2.0.0"

# 릴리스 상태 확인
helm list --all-namespaces

# 릴리스 세부 정보 확인
helm status my-app -n namespace

# 필요 시 강제 삭제 (주의 필요)
kubectl delete secret -n namespace -l owner=helm,name=my-app

# 템플릿 렌더링 디버깅
helm template my-app ./my-application --debug

# Kubernetes에 대해 검증
helm template my-app ./my-application | kubectl apply --dry-run=client -f -

# 병합된 값 확인
helm get values my-app

# 모든 계산된 값 표시
helm get values my-app --all

repositories:
  - name: bitnami
    url: https://charts.bitnami.com/bitnami

releases:
  - name: postgresql
    namespace: database
    chart: bitnami/postgresql
    version: 12.x.x
    values:
      - postgresql:
          auth:
            database: myapp
            username: appuser

  - name: my-app
    namespace: production
    chart: ./charts/my-application
    values:
      - values-production.yaml
    needs:
      - database/postgresql