Add Jetstack Helm repository

플랫폼	명령어
kubectl (Static Manifests)	`kubectl apply -f https://github.com/cert-manager/cert-manager/releases/download/v1.13.3/cert-manager.yaml`
Helm (Recommended)	`helm install cert-manager jetstack/cert-manager --namespace cert-manager --create-namespace --set installCRDs=true`
macOS (cmctl CLI)	`brew install cmctl`
Linux (cmctl CLI)	`curl -sSL https://github.com/cert-manager/cert-manager/releases/download/v1.13.3/cmctl-linux-amd64.tar.gz \
Windows (cmctl CLI)	`curl.exe -L -o cmctl.exe https://github.com/cert-manager/cert-manager/releases/download/v1.13.3/cmctl-windows-amd64.exe`
Verify Installation	`kubectl get pods -n cert-manager`

# Add Jetstack Helm repository
helm repo add jetstack https://charts.jetstack.io

# Update repository
helm repo update

# Install with custom values
helm install cert-manager jetstack/cert-manager \
  --namespace cert-manager \
  --create-namespace \
  --version v1.13.3 \
  --values custom-values.yaml
```## 설치

| 명령어 | 설명 |
|---------|-------------|
| `kubectl get certificates` | 현재 네임스페이스의 모든 인증서 나열 |
| `kubectl get certificates -A` | 모든 네임스페이스에 걸쳐 인증서 나열 |
| `kubectl describe certificate <name>` | 자세한 인증서 정보 표시 |
| `kubectl get certificate <name> -o yaml` | YAML 형식으로 인증서 보기 |
| `kubectl get issuer` | 현재 네임스페이스의 모든 발급자 나열 |
| `kubectl get clusterissuer` | 클러스터 전체 발급자 나열 |
| `kubectl describe issuer <name>` | 발행자 상세 정보 표시 |
| `kubectl get certificaterequest` | 인증서 요청 목록 |
| `kubectl get order` | ACME 인증서 주문 보기 |
| `kubectl get challenge` | ACME 도메인 검증 챌린지 보기 |
| `kubectl logs -n cert-manager deployment/cert-manager` | cert-manager 컨트롤러 로그 보기 |
| `kubectl logs -n cert-manager deployment/cert-manager-webhook` | 웹훅 로그 보기 |
| `kubectl logs -n cert-manager deployment/cert-manager-cainjector` | CA 인젝터 로그 보기 |
| `cmctl check api` | cert-manager API를 사용 가능한지 확인하세요 |
| `cmctl version` | cert-manager 버전 정보 표시 |
| `cmctl status certificate <name>` | 인증서 상태 및 준비 상태 확인 |
| `cmctl inspect secret <secret-name>` | cert-manager에 의해 생성된 TLS 시크릿 검사 |
| `cmctl renew <cert-name>` | 인증서 갱신을 수동으로 트리거 |
| `kubectl get crd \ | grep cert-manager` | cert-manager 사용자 정의 리소스 정의(Custom Resource Definitions) 나열하기 |
| `kubectl get events --field-selector involvedObject.name=<cert-name>` | 특정 인증서와 관련된 이벤트 보기 |### Helm 저장소 설정

| 명령어 | 설명 |
|---------|-------------|
| `cmctl approve <certificaterequest-name>` | 인증서 요청을 수동으로 승인하기 |
| `cmctl deny <certificaterequest-name>` | 인증서 요청 거부 |
| `cmctl create certificaterequest test --from-certificate-file=cert.yaml` | 파일에서 인증서 요청 생성 |
| `cmctl convert --output-format=pem --input-file=cert.yaml` | 인증서를 PEM 형식으로 변환 |
| `cmctl experimental create acmeaccount --server=<url> --email=<email>` | ACME 계정 등록 테스트 |
| `kubectl annotate certificate <name> cert-manager.io/issue-temporary-certificate="true" --overwrite` | 즉시 인증서 갱신 |
| `kubectl delete certificaterequest <name>` | 실패한 인증서 요청 제거 |
| `kubectl delete order <name>` | ACME 주문 삭제 |
| `kubectl delete challenge <name>` | ACME 챌린지 제거 |
| `kubectl get certificate <name> -o jsonpath='{.status.conditions}'` | 인증서 상태 조건 추출 |
| `kubectl get secret <tls-secret> -o jsonpath='{.data.tls\.crt}' \ | base64 -d \ | openssl x509 -text -noout` | 인증서 세부 정보 디코딩 및 보기 |
| `kubectl get secret <tls-secret> -o jsonpath='{.data.tls\.crt}' \ | base64 -d \ | openssl x509 -noout -dates` | 인증서 만료 날짜 확인 |
| `helm upgrade cert-manager jetstack/cert-manager --namespace cert-manager --version v1.13.3` | cert-manager를 새 버전으로 업그레이드 |
| `kubectl rollout restart deployment -n cert-manager` | cert-manager의 모든 구성 요소 재시작 |
| `kubectl scale deployment cert-manager -n cert-manager --replicas=2` | 고가용성을 위한 cert-manager 확장 |
| `kubectl get certificate --watch` | 실시간으로 인증서 상태 변화 확인하기 |
| `kubectl patch certificate <name> --type merge -p '{"spec":{"renewBefore":"720h"}}'` | 인증서 갱신 창 수정 |
| `kubectl delete secret <tls-secret>` | 인증서 시크릿 삭제 (재생성 트리거) |
| `cmctl experimental install` | cmctl 도구를 사용하여 cert-manager 설치 |
| `cmctl experimental uninstall` | cert-manager를 제거하고 리소스 정리하기 |
```yaml
apiVersion: cert-manager.io/v1
kind: ClusterIssuer
metadata:
  name: selfsigned-issuer
spec:
  selfSigned: {}
```## 기본 명령어
```yaml
apiVersion: cert-manager.io/v1
kind: ClusterIssuer
metadata:
  name: letsencrypt-staging
spec:
  acme:
    server: https://acme-staging-v02.api.letsencrypt.org/directory
    email: admin@example.com
    privateKeySecretRef:
      name: letsencrypt-staging
    solvers:
    - http01:
        ingress:
          class: nginx
```## 고급 사용법
```yaml
apiVersion: cert-manager.io/v1
kind: ClusterIssuer
metadata:
  name: letsencrypt-prod
spec:
  acme:
    server: https://acme-v02.api.letsencrypt.org/directory
    email: admin@example.com
    privateKeySecretRef:
      name: letsencrypt-prod
    solvers:
    - dns01:
        cloudDNS:
          project: my-gcp-project
          serviceAccountSecretRef:
            name: clouddns-dns01-solver
            key: key.json
```## 구성
```yaml
apiVersion: cert-manager.io/v1
kind: Issuer
metadata:
  name: ca-issuer
  namespace: default
spec:
  ca:
    secretName: ca-key-pair
```### 자체 서명된 ClusterIssuer
```yaml
apiVersion: cert-manager.io/v1
kind: Certificate
metadata:
  name: example-com
  namespace: default
spec:
  secretName: example-com-tls
  issuerRef:
    name: letsencrypt-prod
    kind: ClusterIssuer
  dnsNames:
  - example.com
  - www.example.com
  duration: 2160h      # 90 days
  renewBefore: 360h    # 15 days before expiry

apiVersion: cert-manager.io/v1
kind: Certificate
metadata:
  name: wildcard-cert
  namespace: default
spec:
  secretName: wildcard-tls
  issuerRef:
    name: letsencrypt-prod
    kind: ClusterIssuer
  dnsNames:
  - "*.example.com"
  - example.com
```### Let's Encrypt 스테이징 (HTTP-01 챌린지)
```yaml
apiVersion: cert-manager.io/v1
kind: Issuer
metadata:
  name: vault-issuer
  namespace: default
spec:
  vault:
    server: https://vault.example.com
    path: pki/sign/example-dot-com
    auth:
      kubernetes:
        mountPath: /v1/auth/kubernetes
        role: cert-manager
        secretRef:
          name: vault-token
          key: token

# custom-values.yaml
installCRDs: true
replicaCount: 2

resources:
  requests:
    cpu: 100m
    memory: 128Mi
  limits:
    cpu: 200m
    memory: 256Mi

prometheus:
  enabled: true
  servicemonitor:
    enabled: true

webhook:
  replicaCount: 2

cainjector:
  replicaCount: 2
```### Let's Encrypt 프로덕션 (DNS-01 챌린지)
```bash
# Create ClusterIssuer
kubectl apply -f - <<EOF
apiVersion: cert-manager.io/v1
kind: ClusterIssuer
metadata:
  name: letsencrypt-prod
spec:
  acme:
    server: https://acme-v02.api.letsencrypt.org/directory
    email: admin@example.com
    privateKeySecretRef:
      name: letsencrypt-prod
    solvers:
    - http01:
        ingress:
          class: nginx
EOF

# Create Ingress with TLS annotation
kubectl apply -f - <<EOF
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: example-ingress
  annotations:
    cert-manager.io/cluster-issuer: "letsencrypt-prod"
spec:
  ingressClassName: nginx
  tls:
  - hosts:
    - example.com
    secretName: example-com-tls
  rules:
  - host: example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: example-service
            port:
              number: 80
EOF

# Verify certificate creation
kubectl get certificate
kubectl describe certificate example-com-tls

# Create self-signed CA
kubectl apply -f - <<EOF
apiVersion: cert-manager.io/v1
kind: ClusterIssuer
metadata:
  name: selfsigned-issuer
spec:
  selfSigned: {}
---
apiVersion: cert-manager.io/v1
kind: Certificate
metadata:
  name: my-ca
  namespace: cert-manager
spec:
  isCA: true
  commonName: my-ca
  secretName: my-ca-secret
  privateKey:
    algorithm: ECDSA
    size: 256
  issuerRef:
    name: selfsigned-issuer
    kind: ClusterIssuer
EOF

# Create CA issuer from generated CA
kubectl apply -f - <<EOF
apiVersion: cert-manager.io/v1
kind: ClusterIssuer
metadata:
  name: my-ca-issuer
spec:
  ca:
    secretName: my-ca-secret
EOF

# Issue service certificates
kubectl apply -f - <<EOF
apiVersion: cert-manager.io/v1
kind: Certificate
metadata:
  name: service-a-cert
  namespace: default
spec:
  secretName: service-a-tls
  duration: 8760h
  renewBefore: 720h
  subject:
    organizations:
    - my-org
  commonName: service-a.default.svc.cluster.local
  dnsNames:
  - service-a.default.svc.cluster.local
  issuerRef:
    name: my-ca-issuer
    kind: ClusterIssuer
EOF
```### CA 발급자 (내부 PKI)
```bash
# Create DNS provider secret (example: Cloudflare)
kubectl create secret generic cloudflare-api-token \
  --from-literal=api-token=YOUR_CLOUDFLARE_API_TOKEN

# Create ClusterIssuer with DNS-01 solver
kubectl apply -f - <<EOF
apiVersion: cert-manager.io/v1
kind: ClusterIssuer
metadata:
  name: letsencrypt-dns
spec:
  acme:
    server: https://acme-v02.api.letsencrypt.org/directory
    email: admin@example.com
    privateKeySecretRef:
      name: letsencrypt-dns
    solvers:
    - dns01:
        cloudflare:
          email: admin@example.com
          apiTokenSecretRef:
            name: cloudflare-api-token
            key: api-token
EOF

# Request wildcard certificate
kubectl apply -f - <<EOF
apiVersion: cert-manager.io/v1
kind: Certificate
metadata:
  name: wildcard-example
  namespace: default
spec:
  secretName: wildcard-example-tls
  issuerRef:
    name: letsencrypt-dns
    kind: ClusterIssuer
  dnsNames:
  - "*.example.com"
  - example.com
EOF

# Monitor certificate issuance
kubectl get certificate wildcard-example -w

# Create certificate for webhook
kubectl apply -f - <<EOF
apiVersion: cert-manager.io/v1
kind: Certificate
metadata:
  name: webhook-cert
  namespace: webhook-system
spec:
  secretName: webhook-server-cert
  duration: 8760h
  renewBefore: 720h
  issuerRef:
    name: selfsigned-issuer
    kind: ClusterIssuer
  dnsNames:
  - webhook-service.webhook-system.svc
  - webhook-service.webhook-system.svc.cluster.local
EOF

# Reference in webhook configuration
kubectl apply -f - <<EOF
apiVersion: admissionregistration.k8s.io/v1
kind: ValidatingWebhookConfiguration
metadata:
  name: my-webhook
  annotations:
    cert-manager.io/inject-ca-from: webhook-system/webhook-cert
webhooks:
- name: webhook.example.com
  clientConfig:
    service:
      name: webhook-service
      namespace: webhook-system
      path: "/validate"
    caBundle: "" # Injected by cert-manager
EOF
```### 인증서 리소스
```bash
# Create certificate with short duration for testing
kubectl apply -f - <<EOF
apiVersion: cert-manager.io/v1
kind: Certificate
metadata:
  name: short-lived-cert
  namespace: default
spec:
  secretName: short-lived-tls
  duration: 24h
  renewBefore: 8h
  issuerRef:
    name: selfsigned-issuer
    kind: ClusterIssuer
  dnsNames:
  - test.example.com
EOF

# Monitor renewal
kubectl get certificate short-lived-cert -w

# Force immediate renewal
kubectl annotate certificate short-lived-cert \
  cert-manager.io/issue-temporary-certificate="true" \
  --overwrite

# Check renewal history
kubectl get certificaterequest -l cert-manager.io/certificate-name=short-lived-cert

# Verify new certificate
cmctl inspect secret short-lived-tls

renewBefore### 와일드카드 인증서 certmanager_certificate_expiration_timestamp_seconds

DNS-01을 와일드카드 및 내부 서비스에 사용: DNS-01 챌린지는 와일드카드 인증서에 필요하며 인터넷에 노출되지 않은 서비스에 더 잘 작동합니다
적절한 RBAC 구현: Kubernetes RBAC을 사용하여 발급자 및 인증서 시크릿에 대한 접근을 제한하여 무단 인증서 생성 방지
구성의 버전 관리: Git에 인증서 및 발급자 매니페스트를 저장하여 변경 사항 추적 및 GitOps 워크플로 활성화
환경별 별도의 발급자 사용: 개발/스테이징/프로덕션을 위해 다른 발급자를 생성하여 자격 증명 격리 및 환경 간 인증서 문제 방지
웹훅에 대한 CA 주입 활성화: 웹훅 구성에 CA 번들을 자동으로 주입하려면 cert-manager.io/inject-ca-from어노테이션 사용
재해 복구 계획: Kubernetes 시크릿에 저장된 CA 개인 키 및 ACME 계정 자격 증명을 외부 보안 저장소에 백업

문제 해결

문제	솔루션
Certificate stuck in “Pending”	Check certificate request: `kubectl describe certificaterequest <name>`. Look for ACME challenge failures or issuer configuration errors
ACME HTTP-01 challenge failing	Verify ingress is accessible: `curl http://<domain>/.well-known/acme-challenge/test`. Check ingress class matches solver configuration
DNS-01 challenge timeout	Confirm DNS provider credentials: `kubectl get secret <dns-secret> -o yaml`. Verify DNS propagation: `dig TXT _acme-challenge.<domain>`
”Too many certificates” rate limit	Let’s Encrypt 스테이징 서버로 전환하거나 7일을 기다리세요. 요율 제한 확인: https://letsencrypt.org/docs/rate-limits/
Certificate not renewing automatically	Check `renewBefore` setting and cert-manager logs: `kubectl logs -n cert-manager deployment/cert-manager`. Verify controller is running
Webhook connection failures	Verify webhook service is running: `kubectl get svc -n cert-manager`. Check webhook certificate validity: `cmctl check api`
CA injection not working	Ensure cainjector is running: `kubectl get pods -n cert-manager`. Verify annotation syntax: `cert-manager.io/inject-ca-from: namespace/certificate`
Certificate shows “Ready=False”	Get detailed status: `cmctl status certificate <name>`. Check events: `kubectl get events --field-selector involvedObject.name=<cert-name>`
Order stuck in “Pending”	Delete order to retry: `kubectl delete order <order-name>`. Certificate controller will create new order automatically
Secret not created after certificate ready	Check secret name matches `secretName` in Certificate spec. Verify namespace: `kubectl get secret <name> -n <namespace>`
Wildcard certificate validation fails	DNS-01 솔버가 구성되었는지 확인하세요 (HTTP-01은 와일드카드를 지원하지 않습니다). TXT 레코드 생성을 위한 DNS 제공자 권한을 확인하세요
Certificate shows wrong issuer	Delete certificate request: `kubectl delete certificaterequest <name>`. Update Certificate spec with correct `issuerRef`
High memory usage	Reduce certificate count or increase resources: `kubectl set resources deployment cert-manager -n cert-manager --limits=memory=512Mi`
Duplicate certificates created	Check for multiple Certificate resources with same `secretName`. Remove duplicates to prevent conflicts
ACME account registration fails	발급자 사양에서 이메일 형식을 확인하세요. ACME 서버 URL이 올바른지 확인하세요. 자세한 오류 메시지를 위해 cert-manager 로그를 검토하세요

# Complete troubleshooting workflow
kubectl describe certificate <cert-name>
kubectl get certificaterequest -l cert-manager.io/certificate-name=<cert-name>
kubectl describe certificaterequest <request-name>
kubectl get order
kubectl describe order <order-name>
kubectl get challenge
kubectl describe challenge <challenge-name>
kubectl logs -n cert-manager deployment/cert-manager --tail=100
```[No text provided]

Would you like me to clarify or complete the missing texts?```bash
# Search for specific certificate errors
kubectl logs -n cert-manager deployment/cert-manager | grep "certificate=<cert-name>"

# Find ACME challenge errors
kubectl logs -n cert-manager deployment/cert-manager | grep "challenge"

# Check for rate limit errors
kubectl logs -n cert-manager deployment/cert-manager | grep "rate limit"

# Monitor certificate renewal attempts
kubectl logs -n cert-manager deployment/cert-manager -f | grep "renewal"