Certificate Management for Kubernetes: Complete Guide

The Challenge of Kubernetes Certificate Management

Kubernetes environments present unique challenges for certificate management:

• Dynamic infrastructure: Pods and services are constantly created and destroyed
• Multiple namespaces: Certificates needed across different teams and applications
• Service mesh complexity: mTLS requires certificates for every service
• Scale: Large clusters may have thousands of certificates

Why Kubernetes CLM Matters

Proper certificate management in Kubernetes is essential for:

• Security: Encrypt all cluster communication
• Compliance: Meet regulatory requirements for data protection
• Reliability: Prevent outages from expired certificates
• Zero trust: Enable service-to-service authentication

Kubernetes Certificate Types

Control Plane Certificates

Critical certificates for cluster operation:

• API server TLS certificate
• etcd server and client certificates
• Controller manager certificates
• Scheduler certificates
• Service account signing key

Ingress Certificates

TLS termination at the cluster edge:

• NGINX Ingress TLS
• Traefik certificates
• Istio Gateway certificates
• AWS ALB/NLB certificates

Service Mesh Certificates

mTLS for service-to-service communication:

• Istio workload certificates
• Linkerd identity certificates
• Consul Connect certificates

Application Certificates

Application-specific certificates:

• Database connection TLS
• External API client certificates
• Webhook server certificates

Implementing cert-manager

Installation

Install cert-manager using Helm:

helm repo add jetstack https://charts.jetstack.io
helm install cert-manager jetstack/cert-manager \
  --namespace cert-manager \
  --create-namespace \
  --set installCRDs=true

Creating Issuers

Let's Encrypt Issuer

apiVersion: cert-manager.io/v1
kind: ClusterIssuer
metadata:
  name: letsencrypt-prod
spec:
  acme:
    server: https://acme-v02.api.letsencrypt.org/directory
    email: [email protected]
    privateKeySecretRef:
      name: letsencrypt-prod-key
    solvers:
    - http01:
        ingress:
          class: nginx

Internal CA Issuer

apiVersion: cert-manager.io/v1
kind: ClusterIssuer
metadata:
  name: internal-ca
spec:
  ca:
    secretName: internal-ca-key-pair

Requesting Certificates

Certificate Resource

apiVersion: cert-manager.io/v1
kind: Certificate
metadata:
  name: api-tls
  namespace: production
spec:
  secretName: api-tls-secret
  issuerRef:
    name: letsencrypt-prod
    kind: ClusterIssuer
  dnsNames:
  - api.example.com
  - api-internal.example.com

Ingress Annotations

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: api-ingress
  annotations:
    cert-manager.io/cluster-issuer: letsencrypt-prod
spec:
  tls:
  - hosts:
    - api.example.com
    secretName: api-tls-secret

Enterprise Kubernetes CLM with TigerTrust

Integration Architecture

TigerTrust integrates with Kubernetes through:

1. TigerTrust Operator: Kubernetes-native certificate management
2. External Secrets Integration: Sync certificates from TigerTrust vault
3. Webhook Receiver: Real-time certificate updates
4. API Integration: Direct API access for automation

Advanced Features

Multi-Cluster Management

Manage certificates across multiple Kubernetes clusters:

• Centralized policy enforcement
• Consistent certificate issuance
• Cross-cluster certificate synchronization
• Unified monitoring and alerting

Enterprise PKI Integration

Connect to your internal PKI:

• Microsoft ADCS integration
• HashiCorp Vault PKI
• TigerTrust PKI Core
• Custom CA support

Compliance and Governance

Enterprise compliance features:

• Certificate policy enforcement
• Audit logging for all operations
• Role-based access control
• Namespace-level policies

Best Practices

Namespace Isolation

• Use separate issuers per namespace when needed
• Implement RBAC for certificate resources
• Consider certificate quotas per namespace

Certificate Lifecycle

• Set appropriate certificate durations
• Configure renewal windows (default 2/3 of lifetime)
• Monitor certificate health with Prometheus metrics

Secret Management

• Enable secret encryption at rest
• Use external secret stores for sensitive certificates
• Implement secret rotation policies
• Audit secret access

High Availability

• Deploy cert-manager with multiple replicas
• Configure proper resource requests/limits
• Use PodDisruptionBudgets
• Implement health checks and alerts

Monitoring Kubernetes Certificates

Prometheus Metrics

Key metrics to monitor:

# Certificate expiry time
certmanager_certificate_expiration_timestamp_seconds

# Certificate ready status
certmanager_certificate_ready_status

# ACME client errors
certmanager_http_acme_client_request_count

Alerting Rules

Example Prometheus alert:

- alert: CertificateExpiringSoon
  expr: certmanager_certificate_expiration_timestamp_seconds - time() < 86400 * 14
  for: 1h
  labels:
    severity: warning
  annotations:
    summary: Certificate expiring in less than 14 days

Conclusion

Kubernetes certificate management requires specialized tooling and practices to handle the dynamic, distributed nature of container environments. By implementing cert-manager with proper enterprise integrations, organizations can achieve automated, secure certificate management at scale.

TigerTrust's Kubernetes CLM capabilities provide enterprise-grade certificate management with deep Kubernetes integration, multi-cluster support, and comprehensive compliance features.