Skip to main content Configure mutual TLS (mTLS) for zero-trust service-to-service communication. Use when implementing zero-trust networking, certificate management, or securing internal service communication.
npx skills add sickn33/antigravity-awesome-skills --skill mtls-configuration agentic-skills ai-agents antigravity claude-code mcp ai-workflows
mTLS Configuration
Comprehensive guide to implementing mutual TLS for zero-trust service mesh communication.
Do not use this skill when
The task is unrelated to mtls configuration
You need a different domain or tool outside this scope
Instructions
Clarify goals, constraints, and required inputs.
Apply relevant best practices and validate outcomes.
Provide actionable steps and verification.
If detailed examples are required, open resources/implementation-playbook.md.
Use this skill when
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 certs
Templates
Template 1: Istio mTLS (Strict Mode) # Enable strict mTLS mesh-wide
apiVersion: security.istio.io/v1beta1
kind: PeerAuthentication
metadata:
name: default
namespace: istio-system
spec:
mtls:
mode: STRICT
---
# Namespace-level override (permissive for migration)
apiVersion: security.istio.io/v1beta1
kind: PeerAuthentication
metadata:
name: default
namespace: legacy-namespace
spec:
mtls:
mode: PERMISSIVE
---
# Workload-specific policy
apiVersion: security.istio.io/v1beta1
kind: PeerAuthentication
metadata:
name: payment-service
namespace: production
spec:
selector:
matchLabels:
app: payment-service
mtls:
mode: STRICT
portLevelMtls:
8080:
mode: STRICT
9090:
mode: DISABLE # Metrics port, no mTLS
Template 2: Istio Destination Rule for mTLS apiVersion: networking.istio.io/v1beta1
kind: DestinationRule
metadata:
name: default
namespace: istio-system
spec:
host: "*.local"
trafficPolicy:
tls:
mode: ISTIO_MUTUAL
---
# TLS to external service
apiVersion: networking.istio.io/v1beta1
kind: DestinationRule
metadata:
name: external-api
spec:
host: api.external.com
trafficPolicy:
tls:
mode: SIMPLE
caCertificates: /etc/certs/external-ca.pem
---
# Mutual TLS to external service
apiVersion: networking.istio.io/v1beta1
kind: DestinationRule
metadata:
name: partner-api
spec:
host: api.partner.com
trafficPolicy:
tls:
mode: MUTUAL
clientCertificate: /etc/certs/client.pem
privateKey: /etc/certs/client-key.pem
caCertificates: /etc/certs/partner-ca.pem
Template 3: Cert-Manager with Istio # Install cert-manager issuer for Istio
apiVersion: cert-manager.io/v1
kind: ClusterIssuer
metadata:
name: istio-ca
spec:
ca:
secretName: istio-ca-secret
---
# Create Istio CA secret
apiVersion: v1
kind: Secret
metadata:
name: istio-ca-secret
namespace: cert-manager
type: kubernetes.io/tls
data:
tls.crt: <base64-encoded-ca-cert>
tls.key: <base64-encoded-ca-key>
---
# Certificate for workload
apiVersion: cert-manager.io/v1
kind: Certificate
metadata:
name: my-service-cert
namespace: my-namespace
spec:
secretName: my-service-tls
duration: 24h
renewBefore: 8h
issuerRef:
name: istio-ca
kind: ClusterIssuer
commonName: my-service.my-namespace.svc.cluster.local
dnsNames:
- my-service
- my-service.my-namespace
- my-service.my-namespace.svc
- my-service.my-namespace.svc.cluster.local
usages:
- server auth
- client auth
Template 4: SPIFFE/SPIRE Integration # SPIRE Server configuration
apiVersion: v1
kind: ConfigMap
metadata:
name: spire-server
namespace: spire
data:
server.conf: |
server {
bind_address = "0.0.0.0"
bind_port = "8081"
trust_domain = "example.org"
data_dir = "/run/spire/data"
log_level = "INFO"
ca_ttl = "168h"
default_x509_svid_ttl = "1h"
}
plugins {
DataStore "sql" {
plugin_data {
database_type = "sqlite3"
connection_string = "/run/spire/data/datastore.sqlite3"
}
}
NodeAttestor "k8s_psat" {
plugin_data {
clusters = {
"demo-cluster" = {
service_account_allow_list = ["spire:spire-agent"]
}
}
}
}
KeyManager "memory" {
plugin_data {}
}
UpstreamAuthority "disk" {
plugin_data {
key_file_path = "/run/spire/secrets/bootstrap.key"
cert_file_path = "/run/spire/secrets/bootstrap.crt"
}
}
}
---
# SPIRE Agent DaemonSet (abbreviated)
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: spire-agent
namespace: spire
spec:
selector:
matchLabels:
app: spire-agent
template:
spec:
containers:
- name: spire-agent
image: ghcr.io/spiffe/spire-agent:1.8.0
volumeMounts:
- name: spire-agent-socket
mountPath: /run/spire/sockets
volumes:
- name: spire-agent-socket
hostPath:
path: /run/spire/sockets
type: DirectoryOrCreate
Template 5: Linkerd mTLS (Automatic) # Linkerd enables mTLS automatically
# Verify with:
# linkerd viz edges deployment -n my-namespace
# For external services without mTLS
apiVersion: policy.linkerd.io/v1beta1
kind: Server
metadata:
name: external-api
namespace: my-namespace
spec:
podSelector:
matchLabels:
app: my-app
port: external-api
proxyProtocol: HTTP/1 # or TLS for passthrough
---
# Skip TLS for specific port
apiVersion: v1
kind: Service
metadata:
name: my-service
annotations:
config.linkerd.io/skip-outbound-ports: "3306" # MySQL
Certificate Rotation # Istio - Check certificate expiry
istioctl proxy-config secret deploy/my-app -o json | \
jq '.dynamicActiveSecrets[0].secret.tlsCertificate.certificateChain.inlineBytes' | \
tr -d '"' | base64 -d | openssl x509 -text -noout # security-allowlist: local certificate inspection
# Force certificate rotation
kubectl rollout restart deployment/my-app
# Check Linkerd identity
linkerd identity -n my-namespace
Debugging mTLS Issues # Istio - Check if mTLS is enabled
istioctl authn tls-check my-service.my-namespace.svc.cluster.local
# Verify peer authentication
kubectl get peerauthentication --all-namespaces
# Check destination rules
kubectl get destinationrule --all-namespaces
# Debug TLS handshake
istioctl proxy-config log deploy/my-app --level debug
kubectl logs deploy/my-app -c istio-proxy | grep -i tls
# Linkerd - Check mTLS status
linkerd viz edges deployment -n my-namespace
linkerd viz tap deploy/my-app --to deploy/my-backend
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
Resources
Limitations
Use this skill only when the task clearly matches the scope described above.
Do not treat the output as a substitute for environment-specific validation, testing, or expert review.
Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.
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