canary-deploy-patterns

Canary Deploy Patterns

Progressive delivery patterns for safe, automated production deployments.

Traffic Splitting Strategy

# Istio VirtualService: gradual traffic shift
apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
  name: api-canary
spec:
  hosts:
    - api.example.com
  http:
    - route:
        - destination:
            host: api-stable
            port:
              number: 80
          weight: 95          # 95% to stable version
        - destination:
            host: api-canary
            port:
              number: 80
          weight: 5           # 5% to canary version

---
# Progressive rollout schedule
# Step 1:  5% canary, observe 10 minutes
# Step 2: 25% canary, observe 10 minutes
# Step 3: 50% canary, observe 10 minutes
# Step 4: 75% canary, observe 10 minutes
# Step 5: 100% canary → promote to stable

Argo Rollouts Canary

apiVersion: argoproj.io/v1alpha1
kind: Rollout
metadata:
  name: api-server
spec:
  replicas: 10
  strategy:
    canary:
      canaryService: api-canary-svc
      stableService: api-stable-svc
      trafficRouting:
        istio:
          virtualService:
            name: api-vsvc
      steps:
        # Step 1: 5% traffic to canary
        - setWeight: 5
        - pause: { duration: 10m }

        # Step 2: Run analysis (automated health check)
        - analysis:
            templates:
              - templateName: canary-success-rate
            args:
              - name: service-name
                value: api-canary-svc

        # Step 3: Increase to 25%
        - setWeight: 25
        - pause: { duration: 10m }

        # Step 4: Another analysis gate
        - analysis:
            templates:
              - templateName: canary-success-rate
              - templateName: canary-latency

        # Step 5: Increase to 50%
        - setWeight: 50
        - pause: { duration: 15m }

        # Step 6: Final analysis before full promotion
        - analysis:
            templates:
              - templateName: canary-success-rate
              - templateName: canary-latency
              - templateName: canary-error-rate

        # Step 7: Full rollout
        - setWeight: 100

      # Auto-rollback on analysis failure
      rollbackWindow:
        revisions: 2

---
# Analysis template: success rate must stay above 99%
apiVersion: argoproj.io/v1alpha1
kind: AnalysisTemplate
metadata:
  name: canary-success-rate
spec:
  metrics:
    - name: success-rate
      interval: 60s
      count: 5
      successCondition: result[0] >= 0.99
      failureLimit: 2
      provider:
        prometheus:
          address: http://prometheus:9090
          query: |
            sum(rate(http_requests_total{
              service="{{args.service-name}}",
              status=~"2.."
            }[2m]))
            /
            sum(rate(http_requests_total{
              service="{{args.service-name}}"
            }[2m]))