Canary routing service to relevant pod.

[chenfli]

Hi,
I am trying to run the canary demo on Argo rollout 1.2 with ArgoCD 2.4.2

My system is based on Nginx for ingress and LinkerD for Service mesh.

Using header-based routing (the user agent, Firefox for example), I route the traffic to the relevant service, which works as planned on the ingress level

I have 2 services but they both require a label selector, which can only be the same one as defined on the rollout.

canary-service

---
apiVersion: v1
kind: Service
metadata:
  name: rollouts-demo-preview
  namespace: rollout-ing
  labels:
    app: rollouts-demo-preview
spec:
  ports:
    - port: 80
      targetPort: http
      protocol: TCP
      name: http
  selector:
    app: rollouts-demo
  type: ClusterIP

Stable service

---
apiVersion: v1
kind: Service
metadata:
  name: rollouts-demo
  namespace: rollout-ing
  labels:
    app: rollouts-demo
spec:
  ports:
    - port: 80
      targetPort: http
      protocol: TCP
      name: http
  selector:
    app: rollouts-demo
  type: ClusterIP

Rollout

apiVersion: argoproj.io/v1alpha1
kind: Rollout
metadata:
  name: rollouts-demo
  namespace: rollout-ing
  labels:
    app: rollouts-demo
spec:
  replicas: 3
  revisionHistoryLimit: 3
  selector:
    matchLabels:
      app: rollouts-demo
  template:
    metadata:
      annotations:
        linkerd.io/inject: enabled
        role: stable  
      labels:
        app: rollouts-demo            
        role: stable        

    spec:
      containers:
        - name: rollouts-demo
          image: alexmt/rollouts-demo:yellow
          ports:
            - name: http
              containerPort: 80
              protocol: TCP
          livenessProbe:
            httpGet:
              path: /
              port: http
          readinessProbe:
            httpGet:
              path: /
              port: http
  strategy:
        canary:
          canaryService: rollouts-demo-preview  # required
          stableService: rollouts-demo  # required
          canaryMetadata:
            annotations:
              role: canary
            labels:
              role: canary
      # metadata which will be attached to the stable pods
          stableMetadata:
            annotations:
              role: stable
            labels:
              role: stable
          trafficRouting:
            smi:
              rootService: rollouts-demo
              trafficSplitName: rollout-demo-traffic-split # optional
            nginx:
              stableIngress: rollouts-demo  # required
              additionalIngressAnnotations:   # optional
                canary-by-header: "User-Agent"
                canary-by-header-pattern: "Mozilla.+Firefox+."
          steps:
          - setWeight: 30
          - pause: {}
          - setWeight: 60
          - pause: {duration: 15s}

Things I did try

canaryMetadata
I did try using canaryMetadata to define which is which, but it only setup the pod level and not the rollout level
I understand that Rollout creates a hash label which can be used, but I don't understand how to use it.

traffic selector
I did try using a traffic selector, but the question is how, since it looks like I need to use label selectors instead

Thanks for your time and feedback.

Chen

[chenfli]

The problem was on the Nginx Ingress,
Using the annotation

nginx.ingress.kubernetes.io/affinity: "cookie"

The stickiness to the stable pods was achieved.