DevOps: How does Argo Rollouts work for Canary deployments?

1apiVersion: argoproj.io/v1alpha1
2kind: Rollout
3metadata:
4  name: myapp
5spec:
6  replicas: 10
7  revisionHistoryLimit: 5
8  selector:
9    matchLabels:
10      app: myapp
11  template:
12    metadata:
13      labels:
14        app: myapp
15    spec:
16      containers:
17        - name: myapp
18          image: myapp:2.0
19  strategy:
20    canary:
21      canaryService: myapp-canary
22      stableService: myapp-stable
23      trafficRouting:
24        istio:
25          virtualServices:
26            - name: myapp-vsvc
27              routes:
28                - primary
29      steps:
30        - setWeight: 5
31        - pause: { duration: 5m }
32        - setWeight: 20
33        - pause: { duration: 10m }
34        - setWeight: 50
35        - pause: { duration: 10m }
36        - setWeight: 100
37      analysis:
38        templates:
39          - templateName: success-rate
40        startingStep: 2

1apiVersion: argoproj.io/v1alpha1
2kind: AnalysisTemplate
3metadata:
4  name: success-rate
5spec:
6  args:
7    - name: service-name
8  metrics:
9    - name: success-rate
10      interval: 2m
11      count: 5
12      successCondition: result[0] >= 0.95
13      provider:
14        prometheus:
15          address: http://prometheus:9090
16          query: |
17            sum(rate(http_requests_total{service="{{args.service-name}}",status=~"2.."}[2m])) /
18            sum(rate(http_requests_total{service="{{args.service-name}}"}[2m]))