# Istio 金絲雀部屬
* Canary是一種發布策略，藍綠部署是準備兩套系統，在兩套系統之間進行切換，金絲雀策略是只有一套系統，逐漸替換這套系統。
* 簡而言之Istio Canary就是一種分流機制他也是做用在VirtualService DestinationRule底下的一種功能透過Service Deployment的labels標籤app version來對應控制該服務所需要流向的端點，以上幾種的組合就可以實踐出服務權重流向的功能。


## 實作
* 需先安裝好 istio
* 在 test namespace 設定 istio auto injection

$ kubectl create ns test

$ kubectl label namespace test istio-injection=enabled

* 部屬 v1 版本

$ echo 'apiVersion: apps/v1
kind: Deployment
metadata:
  name: helloworld-v1
  namespace: test
spec:
  replicas: 1
  selector:
    matchLabels:
      app: helloworld
      version: v1
  template:
    metadata:
      labels:
        app: helloworld
        version: v1
    spec:
      containers:
      - name: app
        image: quay.io/flysangel/image:app.golang' | kubectl apply -f -

* 部屬 v2 版本

$ echo 'apiVersion: apps/v1
kind: Deployment
metadata:
  name: helloworld-v2
  namespace: test
spec:
  replicas: 1
  selector:
    matchLabels:
      app: helloworld
      version: v2
  template:
    metadata:
      labels:
        app: helloworld
        version: v2
    spec:
      containers:
      - name: app
        image: quay.io/flysangel/image:app.golang' | kubectl apply -f -

* 建立 svc

$ echo 'apiVersion: v1
kind: Service
metadata:
  name: helloworld
  namespace: test
spec:
  selector:
    app: helloworld
  ports:
    - protocol: TCP
      port: 80
      targetPort: 8080' | kubectl apply -f -

* 檢查

$ kubectl -n test get all
NAME                                 READY   STATUS    RESTARTS   AGE
pod/helloworld-v1-688bdcf9f8-sx975   2/2     Running   0          42s
pod/helloworld-v2-84d5d87fff-2qchg   2/2     Running   0          27s

NAME                 TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)   AGE
service/helloworld   ClusterIP   10.43.201.252   <none>        80/TCP    7s

NAME                            READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/helloworld-v1   1/1     1            1           42s
deployment.apps/helloworld-v2   1/1     1            1           27s

NAME                                       DESIRED   CURRENT   READY   AGE
replicaset.apps/helloworld-v1-688bdcf9f8   1         1         1       42s
replicaset.apps/helloworld-v2-84d5d87fff   1         1         1       27s

## 建立 gateway

$ echo 'apiVersion: networking.istio.io/v1beta1
kind: Gateway
metadata:
  name: canary-gateway
  namespace: test
spec:
  selector:
    istio: ingressgateway
  servers:
  - port: 
      name: http
      number: 80  # ingress-gateway port num
      protocol: HTTP
    hosts:
    - "*"' | kubectl apply -f -

$ kubectl -n test get gateway.networking
NAME             AGE
canary-gateway   18s

## 建立 VirtualService
* 設計 90% 的流量到 v1，10% 的流量到 v2

$ echo 'apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: helloworld
  namespace: test
spec:
  gateways:
  - canary-gateway
  hosts:
  - "*"
  http:
  - route:
    - destination:
        host: helloworld.test.svc.cluster.local
        subset: v1
      weight: 90
    - destination:
        host: helloworld.test.svc.cluster.local
        subset: v2
      weight: 10' | kubectl apply -f -

$ kubectl -n test get virtualService
NAME         GATEWAYS             HOSTS   AGE
helloworld   ["canary-gateway"]   ["*"]   38s

## 建立 DestinationRule

$ echo 'apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: helloworld
  namespace: test
spec:
  host: helloworld.test.svc.cluster.local
  subsets:
  - name: v1
    labels:
      version: v1
  - name: v2
    labels:
      version: v2' | kubectl apply -f -

$ kubectl -n test get destinationRule
NAME         HOST                                AGE
helloworld   helloworld.test.svc.cluster.local   4s

## 驗證

$ kubectl get svc -n istio-system
NAME                   TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)                                                                      AGE
istio-ingressgateway   NodePort    10.43.10.193    <none>        15021:30214/TCP,80:31380/TCP,443:31390/TCP,31400:31400/TCP,15443:32475/TCP   63d
istiod                 ClusterIP   10.43.113.109   <none>        15010/TCP,15012/TCP,443/TCP,15014/TCP                                        63d
jaeger-collector       ClusterIP   10.43.81.157    <none>        14268/TCP,14250/TCP                                                          63d
kiali                  ClusterIP   10.43.26.41     <none>        20001/TCP,9090/TCP                                                           63d
tracing                ClusterIP   10.43.98.84     <none>        16686/TCP                                                                    63d
zipkin                 ClusterIP   10.43.225.85    <none>        9411/TCP                                                                     63d

* 使用 nodeport 方式 curl，90% 流量會到 v1，10% 流量會到 v2

$ curl -w "\n" 192.168.11.110:31380/hostname
{"message":"helloworld-v1-688bdcf9f8-sx975"}
$ curl -w "\n" 192.168.11.110:31380/hostname
{"message":"helloworld-v1-688bdcf9f8-sx975"}
$ curl -w "\n" 192.168.11.110:31380/hostname
{"message":"helloworld-v1-688bdcf9f8-sx975"}
$ curl -w "\n" 192.168.11.110:31380/hostname
{"message":"helloworld-v1-688bdcf9f8-sx975"}
$ curl -w "\n" 192.168.11.110:31380/hostname
{"message":"helloworld-v1-688bdcf9f8-sx975"}
$ curl -w "\n" 192.168.11.110:31380/hostname
{"message":"helloworld-v1-688bdcf9f8-sx975"}
$ curl -w "\n" 192.168.11.110:31380/hostname
{"message":"helloworld-v2-84d5d87fff-2qchg"}

$ while true; do curl -w "\n" http://192.168.11.110:31380/hostname; sleep 0.1; done

* 可以在 istio 介面上可以看到流量分布



## 參考文件
https://blog.csdn.net/qq_41586875/article/details/124384114