Istio配置文件中的host

May 18, 2021

不使用gateway的情况

如果没有gw，那么只需要 DestinationRule 和 VirtualService 就可以了

在DestinationRule中，host 需要对应的是 Kubernetes中的service

apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: nginx-desrule 
  namespace: lizhe
spec: 
  host: nginx-service
  subsets:
  - name: v1 
    labels: 
      version: v1
  - name: v2
    labels: 
      version: v2
  - name: v3
    labels: 
      version: v3

对应的VirtualService

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: nginx-default
  namespace: version
spec: 
  hosts:
  - nginx-service
  http:
  - route: 
    - destination: 
        host: nginx-service
        subset: v2

此时使用以下3种内部dns都可以访问

curl nginx-service/helloworld.html
curl nginx-service.version/helloworld.html
curl nginx-service.version.svc/helloworld.html

使用Gateway的情况

创建一个 Gateway

apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
  name: nginx-gateway
  namespace: version
spec:
  selector:
    istio: ingressgateway # use istio default controller
  servers:
  - port:
      number: 80
      name: http
      protocol: HTTP
    hosts:
    - "*.lizhe.com"

再创建DestinationRule

apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: nginx-desrule 
  namespace: version
spec: 
  host: nginx-service.version.svc.cluster.local
  subsets:
  - name: v1 
    labels: 
      version: v1
  - name: v2
    labels: 
      version: v2
  - name: v3
    labels: 
      version: v3

最后用一个VirtualService把它们两个粘在一起

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: nginx-default-v2
  namespace: version
spec:
  hosts:
  - "hello.lizhe.com"
  gateways:
  - nginx-gateway
  http:
  - route:
    - destination:
        host: nginx-service.version.svc.cluster.local
        subset: v2

对于service可以使用全量名

下面是一个错误例子

不过可以使用通配符 *

root@istio1:~/yamls# cat dr.yaml 
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: nginx-desrule 
  namespace: version
spec: 
  host: nginx-service.version.svc.cluster.local
  subsets:
  - name: v2
    labels: 
      version: v2

root@istio1:~/yamls# cat vs.yaml 
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: nginx-default
  namespace: version
spec: 
  hosts:
  - "*.version.svc.cluster.local"
  http:
  - route: 
    - destination: 
        host: nginx-service.version.svc.cluster.local
        subset: v2

root@istio1:~/yamls# kubectl apply -f ./
destinationrule.networking.istio.io/nginx-desrule unchanged
virtualservice.networking.istio.io/nginx-default configured
root@istio1:~/yamls#

gw和vs匹配