🤖system prompt•7 months ago
linkerd-patterns
Implement Linkerd service mesh patterns for lightweight,
architecture
⭐1
# Linkerd Patterns
Production patterns for Linkerd service mesh - the lightweight, security-first service mesh for Kubernetes.
## When to Use This Skill
- Setting up a lightweight service mesh
- Implementing automatic mTLS
- Configuring traffic splits for canary deployments
- Setting up service profiles for per-route metrics
- Implementing retries and timeouts
- Multi-cluster service mesh
## Core Concepts
### 1. Linkerd Architecture
```
┌─────────────────────────────────────────────┐
│ Control Plane │
│ ┌─────────┐ ┌──────────┐ ┌──────────────┐ │
│ │ destiny │ │ identity │ │ proxy-inject │ │
│ └─────────┘ └──────────┘ └──────────────┘ │
└─────────────────────────────────────────────┘
│
┌─────────────────────────────────────────────┐
│ Data Plane │
│ ┌─────┐ ┌─────┐ ┌─────┐ │
│ │proxy│────│proxy│────│proxy│ │
│ └─────┘ └─────┘ └─────┘ │
│ │ │ │ │
│ ┌──┴──┐ ┌──┴──┐ ┌──┴──┐ │
│ │ app │ │ app │ │ app │ │
│ └─────┘ └─────┘ └─────┘ │
└─────────────────────────────────────────────┘
```
### 2. Key Resources
| Resource | Purpose |
| ----------------------- | ------------------------------------ |
| **ServiceProfile** | Per-route metrics, retries, timeouts |
| **TrafficSplit** | Canary deployments, A/B testing |
| **Server** | Define server-side policies |
| **ServerAuthorization** | Access control policies |
## Templates
### Template 1: Mesh Installation
```bash
# Install CLI
curl --proto '=https' --tlsv1.2 -sSfL https://run.linkerd.io/install | sh
# Validate cluster
linkerd check --pre
# Install CRDs
linkerd install --crds | kubectl apply -f -
# Install control plane
linkerd install | kubectl apply -f -
# Verify installation
linkerd check
# Install viz extension (optional)
linkerd viz install | kubectl apply -f -
```
### Template 2: Inject Namespace
```yaml
# Automatic injection for namespace
apiVersion: v1
kind: Namespace
metadata:
name: my-app
annotations:
linkerd.io/inject: enabled
---
# Or inject specific deployment
apiVersion: apps/v1
kind: Deployment
metadata:
name: my-app
annotations:
linkerd.io/inject: enabled
spec:
template:
metadata:
annotations:
linkerd.io/inject: enabled
```
### Template 3: Service Profile with Retries
```yaml
apiVersion: linkerd.io/v1alpha2
kind: ServiceProfile
metadata:
name: my-service.my-namespace.svc.cluster.local
namespace: my-namespace
spec:
routes:
- name: GET /api/users
condition:
method: GET
pathRegex: /api/users
responseClasses:
- condition:
status:
min: 500
max: 599
isFailure: true
isRetryable: true
- name: POST /api/users
condition:
method: POST
pathRegex: /api/users
# POST not retryable by default
isRetryable: false
- name: GET /api/users/{id}
condition:
method: GET
pathRegex: /api/users/[^/]+
timeout: 5s
isRetryable: true
retryBudget:
retryRatio: 0.2
minRetriesPerSecond: 10
ttl: 10s
```
### Template 4: Traffic Split (Canary)
```yaml
apiVersion: split.smi-spec.io/v1alpha1
kind: TrafficSplit
metadata:
name: my-service-canary
namespace: my-namespace
spec:
service: my-service
backends:
- service: my-service-stable
weight: 900m # 90%
- service: my-service-canary
weight: 100m # 10%
```
### Template 5: Server Authorization Policy
```yaml
# Define the server
apiVersion: policy.linkerd.io/v1beta1
kind: Server
metadata:
name: my-service-http
namespace: my-namespace
spec:
podSelector:
matchLabels:
app: my-service
port: http
proxyProtocol: HTTP/1
---
# Allow traffic from specific clients
apiVersion: policy.linkerd.io/v1beta1
kind: ServerAuthorization
metadata:
name: allow-frontend
namespace: my-namespace
spec:
server:
name: my-service-http
client:
meshTLS:
serviceAccounts:
- name: frontend
namespace: my-namespace
---
# Allow unauthenticated traffic (e.g., from ingress)
apiVersion: policy.linkerd.io/v1beta1
kind: ServerAuthorization
metadata:
name: allow-ingress
namespace: my-namespace
spec:
server:
name: my-service-http
client:
unauthenticated: true
networks:
- cidr: 10.0.0.0/8
```
### Template 6: HTTPRoute for Advanced Routing
```yaml
apiVersion: policy.linkerd.io/v1beta2
kind: HTTPRoute
metadata:
name: my-route
namespace: my-namespace
spec:
parentRefs:
- name: my-service
kind: Service
group: core
port: 8080
rules:
- matches:
- path:
type: PathPrefix
value: /api/v2
- headers:
- name: x-api-version
value: v2
backendRefs:
- name: my-service-v2
port: 8080
- matches:
- path:
type: PathPrefix
value: /api
backendRefs:
- name: my-service-v1
port: 8080
```
### Template 7: Multi-cluster Setup
```bash
# On each cluster, install with cluster credentials
linkerd multicluster install | kubectl apply -f -
# Link clusters
linkerd multicluster link --cluster-name west \
--api-server-address https://west.example.com:6443 \
| kubectl apply -f -
# Export a service to other clusters
kubectl label svc/my-service mirror.linkerd.io/exported=true
# Verify cross-cluster connectivity
linkerd multicluster check
linkerd multicluster gateways
```
## Monitoring Commands
```bash
# Live traffic view
linkerd viz top deploy/my-app
# Per-route metrics
linkerd viz routes deploy/my-app
# Check proxy status
linkerd viz stat deploy -n my-namespace
# View service dependencies
linkerd viz edges deploy -n my-namespace
# Dashboard
linkerd viz dashboard
```
## Debugging
```bash
# Check injection status
linkerd check --proxy -n my-namespace
# View proxy logs
kubectl logs deploy/my-app -c linkerd-proxy
# Debug identity/TLS
linkerd identity -n my-namespace
# Tap traffic (live)
linkerd viz tap deploy/my-app --to deploy/my-backend
```
## Best Practices
### Do's
- **Enable mTLS everywhere** - It's automatic with Linkerd
- **Use ServiceProfiles** - Get per-route metrics and retries
- **Set retry budgets** - Prevent retry storms
- **Monitor golden metrics** - Success rate, latency, throughput
### Don'ts
- **Don't skip check** - Always run `linkerd check` after changes
- **Don't over-configure** - Linkerd defaults are sensible
- **Don't ignore ServiceProfiles** - They unlock advanced features
- **Don't forget timeouts** - Set appropriate values per route
## Resources
- [Linkerd Documentation](https://linkerd.io/2.14/overview/)
- [Service Profiles](https://linkerd.io/2.14/features/service-profiles/)
- [Authorization Policy](https://linkerd.io/2.14/features/server-policy/)
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