mTLS Configuration
Comprehensive guide to implementing mutual TLS for zero-trust service mesh communication.
When to Use This Skill
- Implementing zero-trust networking
- Securing service-to-service communication
- Certificate rotation and management
- Debugging TLS handshake issues
- Compliance requirements (PCI-DSS, HIPAA)
- Multi-cluster secure communication
Core Concepts
1. mTLS Flow
┌─────────┐ ┌─────────┐
│ Service │ │ Service │
│ A │ │ B │
└────┬────┘ └────┬────┘
│ │
┌────┴────┐ TLS Handshake ┌────┴────┐
│ Proxy │◄───────────────────────────►│ Proxy │
│(Sidecar)│ 1. ClientHello │(Sidecar)│
│ │ 2. ServerHello + Cert │ │
│ │ 3. Client Cert │ │
│ │ 4. Verify Both Certs │ │
│ │ 5. Encrypted Channel │ │
└─────────┘ └─────────┘2. Certificate Hierarchy
Root CA (Self-signed, long-lived)
│
├── Intermediate CA (Cluster-level)
│ │
│ ├── Workload Cert (Service A)
│ └── Workload Cert (Service B)
│
└── Intermediate CA (Multi-cluster)
│
└── Cross-cluster certsTemplates and detailed worked examples
Full template library and detailed worked examples live in references/details.md. Read that file when you need the concrete templates.
Best Practices
Do's
- Start with PERMISSIVE - Migrate gradually to STRICT
- Monitor certificate expiry - Set up alerts
- Use short-lived certs - 24h or less for workloads
- Rotate CA periodically - Plan for CA rotation
- Log TLS errors - For debugging and audit
Don'ts
- Don't disable mTLS - For convenience in production
- Don't ignore cert expiry - Automate rotation
- Don't use self-signed certs - Use proper CA hierarchy
- Don't skip verification - Verify the full chain
