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Plattform Befehl
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 \ | tar xz && sudo mv cmctl /usr/local/bin
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
```## Installation

| Befehl | Beschreibung |
|---------|-------------|
| `kubectl get certificates` | Alle Zertifikate im aktuellen Namespace auflisten |
| `kubectl get certificates -A` | Zertifikate über alle Namespaces auflisten |
| `kubectl describe certificate <name>` | Detaillierte Zertifikatsinformationen anzeigen |
| `kubectl get certificate <name> -o yaml` | Zertifikat im YAML-Format anzeigen |
| `kubectl get issuer` | Alle Aussteller im aktuellen Namespace auflisten |
| `kubectl get clusterissuer` | Alle clusterweiten Issuer auflisten |
| `kubectl describe issuer <name>` | Detaillierte Aussteller-Informationen anzeigen |
| `kubectl get certificaterequest` | Zertifikatanfragen auflisten |
| `kubectl get order` | ACME-Zertifikatsbestellungen anzeigen |
| `kubectl get challenge` | ACME-Herausforderungen zur Domainvalidierung anzeigen |
| `kubectl logs -n cert-manager deployment/cert-manager` | cert-manager Controller-Logs anzeigen |
| `kubectl logs -n cert-manager deployment/cert-manager-webhook` | Webhook-Logs anzeigen |
| `kubectl logs -n cert-manager deployment/cert-manager-cainjector` | CA Injector-Logs anzeigen |
| `cmctl check api` | Überprüfen Sie, ob die cert-manager API verfügbar ist |
| `cmctl version` | Zeige cert-manager Versionsinformationen |
| `cmctl status certificate <name>` | Zertifikatsstatus und -bereitschaft prüfen |
| `cmctl inspect secret <secret-name>` | TLS-Geheimnis untersuchen, das von cert-manager erstellt wurde |
| `cmctl renew <cert-name>` | Zertifikaterneuerung manuell auslösen |
| `kubectl get crd \ | grep cert-manager` | Auflisten aller cert-manager Custom Resource Definitions |
| `kubectl get events --field-selector involvedObject.name=<cert-name>` | Ereignisse anzeigen, die mit einem bestimmten Zertifikat zusammenhängen |### Helm Repository Setup

| Befehl | Beschreibung |
|---------|-------------|
| `cmctl approve <certificaterequest-name>` | Zertifikatanfrage manuell genehmigen |
| `cmctl deny <certificaterequest-name>` | Zertifikatanfrage ablehnen |
| `cmctl create certificaterequest test --from-certificate-file=cert.yaml` | Zertifikatanfrage aus Datei erstellen |
| `cmctl convert --output-format=pem --input-file=cert.yaml` | Zertifikat in PEM-Format konvertieren |
| `cmctl experimental create acmeaccount --server=<url> --email=<email>` | ACME-Konto-Registrierung testen |
| `kubectl annotate certificate <name> cert-manager.io/issue-temporary-certificate="true" --overwrite` | Sofortige Zertifikatserneuerung erzwingen |
| `kubectl delete certificaterequest <name>` | Fehlgeschlagene Zertifikatsanfrage entfernen |
| `kubectl delete order <name>` | ACME-Bestellung löschen |
| `kubectl delete challenge <name>` | Stuck ACME-Challenge entfernen |
| `kubectl get certificate <name> -o jsonpath='{.status.conditions}'` | Zertifikatsstatus-Bedingungen extrahieren |
| `kubectl get secret <tls-secret> -o jsonpath='{.data.tls\.crt}' \ | base64 -d \ | openssl x509 -text -noout` | Zertifikat entschlüsseln und Details anzeigen |
| `kubectl get secret <tls-secret> -o jsonpath='{.data.tls\.crt}' \ | base64 -d \ | openssl x509 -noout -dates` | Zertifikatsablaufdaten überprüfen |
| `helm upgrade cert-manager jetstack/cert-manager --namespace cert-manager --version v1.13.3` | Upgrade cert-manager auf neue Version |
| `kubectl rollout restart deployment -n cert-manager` | Starten Sie alle cert-manager-Komponenten neu |
| `kubectl scale deployment cert-manager -n cert-manager --replicas=2` | Skalieren von cert-manager für Hochverfügbarkeit |
| `kubectl get certificate --watch` | Zertifikatsstatus-Änderungen in Echtzeit beobachten |
| `kubectl patch certificate <name> --type merge -p '{"spec":{"renewBefore":"720h"}}'` | Zertifikaterneuerungsfenster ändern |
| `kubectl delete secret <tls-secret>` | Zertifikatgeheimnis löschen (löst Neuerstellen aus) |
| `cmctl experimental install` | Installieren Sie cert-manager mit dem cmctl-Tool |
| `cmctl experimental uninstall` | cert-manager deinstallieren und Ressourcen bereinigen |## Grundlegende Befehle
```yaml
apiVersion: cert-manager.io/v1
kind: ClusterIssuer
metadata:
  name: selfsigned-issuer
spec:
  selfSigned: {}
```## Erweiterte Nutzung
```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
```## Konfiguration
```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
```### Selbstsignierter ClusterIssuer
```yaml
apiVersion: cert-manager.io/v1
kind: Issuer
metadata:
  name: ca-issuer
  namespace: default
spec:
  ca:
    secretName: ca-key-pair
```### CA Issuer (Interne PKI)
```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
```### Zertifikatsressource
```yaml
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
```### Wildcard-Zertifikat
```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
```### Vault Issuer
```yaml
# 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
```### Helm-Werte-Konfiguration
```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
```## Häufige Anwendungsfälle
```bash
# 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
```### Anwendungsfall 1: Sichere Ingress mit Let's Encrypt
```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
```### Anwendungsfall 2: Interner Service mTLS
```bash
# 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
```### Anwendungsfall 3: Wildcard-Zertifikat mit DNS-01
```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
```### Anwendungsfall 4: Sichern von Kubernetes-Webhooks
`renewBefore`### Anwendungsfall 5: Zertifikatsrotation und -erneuerung
`certmanager_certificate_expiration_timestamp_seconds`
- **DNS-01 für Wildcards und interne Services verwenden**: DNS-01 Challenge ist erforderlich für Wildcard-Zertifikate und funktioniert besser für Services, die nicht im Internet exponiert sind

- **Ordnungsgemäße RBAC implementieren**: Zugriff auf Issuers und Zertifikat-Secrets mit Kubernetes RBAC einschränken, um unbefugte Zertifikatserstellung zu verhindern

- **Konfigurationen unter Versionskontrolle stellen**: Certificate und Issuer Manifeste in Git speichern, um Änderungen zu verfolgen und GitOps-Workflows zu ermöglichen

- **Separate Issuers pro Umgebung verwenden**: Verschiedene Issuers für Entwicklungs-/Staging-/Produktionsumgebungen erstellen, um Zugangsdaten zu isolieren und umgebungsübergreifende Zertifikatsprobleme zu verhindern

- **CA-Injektion für Webhooks aktivieren**: Annotation verwenden, um automatisch CA-Bundles in Webhook-Konfigurationen zu injizieren
`cert-manager.io/inject-ca-from`
- **Plan for disaster recovery**: Backup CA private keys and ACME account credentials stored in Kubernetes secrets to external secure storage

## Troubleshooting

| Problem | Lösung |
|-------|----------|
| **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** | Wechseln Sie zum Let's Encrypt Staging-Server oder warten Sie 7 Tage. Überprüfen Sie die Ratenlimits: 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** | Stellen Sie sicher, dass der DNS-01-Solver konfiguriert ist (HTTP-01 unterstützt keine Wildcards). Überprüfen Sie die Berechtigungen des DNS-Providers für die Erstellung von TXT-Einträgen |
| **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** | E-Mail-Format im Issuer-Spec überprüfen. ACME-Server-URL auf Korrektheit prüfen. Cert-manager-Logs für detaillierte Fehlermeldungen durchsehen |
### Debug Command Sequence
```bash
# 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
### Common Log Patterns

Note: It seems like some texts are missing or incomplete. I've translated what was provided, but texts 2, 3, and 4 appear to be incomplete or identical to the original.```bash

Search for specific certificate errors

kubectl logs -n cert-manager deployment/cert-manager | grep "certificate="

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" ```