istio(2):流量管理-基于不同版本访问规则控制
istio-流量管理-基于不同版本访问规则控制
目前搭建 Bookinfo 应用我们只用到了下面两个资源文件:
samples/bookinfo/platform/kube/bookinfo.yaml
samples/bookinfo/networking/bookinfo-gateway.yaml
前者就是通常的k8s
定义的 Deployment 和 Service 的 yaml 文件,只是在部署时使用istioctl kube-inject
对这个文件定义的pod
注入了sidecar
代理,后者定义了这个应用的外部访问入口gateway
,以及应用内部 productpage 服务的VirtualService
规则,而其他内部服务的访问规则还没有被定义。
可以看到当前集群中的gateway
:
[root@k8s-master ~]# kubectl get gateway --all-namespaces NAMESPACE NAME AGE default bookinfo-gateway 2d22h [root@k8s-master ~]# istioctl get gateway Command "get" is deprecated, Use `kubectl get` instead (see https://kubernetes.io/docs/tasks/tools/install-kubectl) GATEWAY NAME HOSTS NAMESPACE AGE bookinfo-gateway * default 2d [root@k8s-master ~]#
现在访问应用界面并刷新,会看到 Reviews 有时不会显示评分,有时候会显示不同样式的评分,因为后面有3个不同的Reviews 服务版本,而没有配置该服务的路由规则route rule的情况下,该服务的几个实例会被随机访问到,有的版本服务会进一步调用 Ratings 服务,有的不会。
不同服务版本访问规则的基本使用
v3版本
现在我们来对 Reviews 服务添加一条路由规则,启用samples/bookinfo/networking/virtual-service-reviews-v3.yaml 定义的VirtualService
规则,内容如下:
apiVersion: networking.istio.io/v1alpha3 kind: VirtualService metadata: name: reviews spec: hosts: - reviews http: - route: - destination: host: reviews subset: v3
这样,所有访问 reviews 服务的流量就会被引导到 reviews 服务对应的 subset 为 v3 的 Pod 中。启用这条规则:
# kubectl apply -f samples/bookinfo/networking/virtual-service-reviews-v3.yaml The VirtualService "reviews" is invalid: []: Invalid value: map[string]interface {}{"apiVersion":"networking.istio.io/v1alpha3", "kind":"VirtualService", "metadata":map[string]interface {}{"annotations":map[string]interface {}{"kubectl.kubernetes.io/last-applied-configuration":"{\"apiVersion\":\"networking.istio.io/v1alpha3\",\"kind\":\"VirtualService\",\"metadata\":{\"annotations\":{},\"name\":\"reviews\",\"namespace\":\"default\"},\"spec\":{\"hosts\":[\"reviews\"],\"http\":[{\"route\":[{\"destination\":{\"host\":\"reviews\",\"subset\":\"v3\"}}],\"weight\":1}]}}\n"}, "creationTimestamp":"2019-11-11T02:31:37Z", "generation":1, "name":"reviews", "namespace":"default", "uid":"6e26b97e-18d9-4c38-87fa-a9f524f3184d"}, "spec":map[string]interface {}{"hosts":[]interface {}{"reviews"}, "http":[]interface {}{map[string]interface {}{"route":[]interface {}{map[string]interface {}{"destination":map[string]interface {}{"host":"reviews", "subset":"v3"}}}, "weight":1}}}}: validation failure list: spec.http.route.weight in body is required #我们修改一下 # cat samples/bookinfo/networking/virtual-service-reviews-v3.yaml apiVersion: networking.istio.io/v1alpha3 kind: VirtualService metadata: name: reviews spec: hosts: - reviews http: - route: - destination: host: reviews subset: v3 weight : 1 [root@k8s-master istio-1.3.1]# vim samples/bookinfo/networking/virtual-service-reviews-v3.yaml [root@k8s-master istio-1.3.1]# kubectl apply -f samples/bookinfo/networking/virtual-service-reviews-v3.yaml virtualservice.networking.istio.io/reviews created
然后查看所有的路由规则:
[root@k8s-master istio-1.3.1]# istioctl get virtualservices Command "get" is deprecated, Use `kubectl get` instead (see https://kubernetes.io/docs/tasks/tools/install-kubectl) VIRTUAL-SERVICE NAME GATEWAYS HOSTS #HTTP #TCP NAMESPACE AGE bookinfo bookinfo-gateway * 1 0 default 2d reviews reviews 1 0 default 1m [root@k8s-master istio-1.3.1]# kubectl get virtualservices NAME GATEWAYS HOSTS AGE bookinfo [bookinfo-gateway] [*] 2d23h reviews [reviews] 114s [root@k8s-master istio-1.3.1]#
可以看到 reviews 的VirtualService已经创建成功了,但是此时刷新应用页面,发现访问 Reviews 失败了:
这是因为我们还没有创建DestinationRule
,DestinationRule
将VirtualService
中指定的subset
与 pod 的{labels:{version: v3}}
关联起来。
在 samples/bookinfo/networking/destination-rule-all.yaml 文件中有定义所有该应用中要用到的所有DestinationRule,其中有一段就是对 Reviews 相关的 DestinationRule 的定义:
# cat samples/bookinfo/networking/destination-rule-all.yaml apiVersion: networking.istio.io/v1alpha3 kind: DestinationRule metadata: name: productpage spec: host: productpage subsets: - name: v1 labels: version: v1 --- apiVersion: networking.istio.io/v1alpha3 kind: DestinationRule metadata: name: reviews spec: host: reviews subsets: - name: v1 labels: version: v1 - name: v2 labels: version: v2 - name: v3 labels: version: v3 --- apiVersion: networking.istio.io/v1alpha3 kind: DestinationRule metadata: name: ratings spec: host: ratings subsets: - name: v1 labels: version: v1 - name: v2 labels: version: v2 - name: v2-mysql labels: version: v2-mysql - name: v2-mysql-vm labels: version: v2-mysql-vm --- apiVersion: networking.istio.io/v1alpha3 kind: DestinationRule metadata: name: details spec: host: details subsets: - name: v1 labels: version: v1 - name: v2 labels: version: v2 ---
可以看到 DestinationRule 中定义了 subsets 集合,其中 labels 就和我们之前 service 的 labelselector 一样是去匹配 Pod 的 labels 标签的,比如我们这里 subsets 中就包含一个名为 v3 的 subset,而这个 subset 匹配的就是具有 version=v3 这个 label 标签的 Pod 集合,再回到之前的 samples/bookinfo/platform/kube/bookinfo.yaml 文件中,我们可以发现 reviews 的 Deployment 确实有声明不同的 labels->version:
--- apiVersion: apps/v1 kind: Deployment metadata: name: reviews-v3 labels: app: reviews version: v3 spec: replicas: 1 selector: matchLabels: app: reviews version: v3 template: metadata: labels: app: reviews version: v3 spec: serviceAccountName: bookinfo-reviews containers: - name: reviews image: docker.io/istio/examples-bookinfo-reviews-v3:1.15.0 imagePullPolicy: IfNotPresent ports: - containerPort: 9080
通过 DestinationRule 将 VirtualService 与 service 不同的版本关联起来了。
现在我们直接创建 DestinationRule 资源:
# kubectl apply -f samples/bookinfo/networking/destination-rule-all.yaml destinationrule.networking.istio.io/productpage created destinationrule.networking.istio.io/reviews created destinationrule.networking.istio.io/ratings created destinationrule.networking.istio.io/details created
创建完成后,我们就可以查看目前我们网格中的 DestinationRules:
# kubectl get destinationrules.networking.istio.io NAME HOST AGE details details 29s productpage productpage 29s ratings ratings 29s reviews reviews 29s # istioctl get destinationrule Command "get" is deprecated, Use `kubectl get` instead (see https://kubernetes.io/docs/tasks/tools/install-kubectl) DESTINATION-RULE NAME HOST SUBSETS NAMESPACE AGE details details v1,v2 default 2m productpage productpage v1 default 2m ratings ratings v1,v2,v2-mysql,v2-mysql-vm default 2m reviews reviews v1,v2,v3 default 2m
此时再访问应用就成功了,多次刷新页面发现 Reviews 都展示的是 v3 版本带红色星的 Ratings,说明我们VirtualService 的配置成功了。
v1版本
首先移除刚刚创建的 VirtualService 对象:
[root@k8s-master bookinfo]# kubectl get virtualservices NAME GATEWAYS HOSTS AGE bookinfo [bookinfo-gateway] [*] 2d23h reviews [reviews] 15m [root@k8s-master bookinfo]# istioctl delete virtualservice reviews Command "delete" is deprecated, Use `kubectl delete` instead (see https://kubernetes.io/docs/tasks/tools/install-kubectl) Deleted config: virtualservice reviews [root@k8s-master bookinfo]# kubectl get virtualservices NAME GATEWAYS HOSTS AGE bookinfo [bookinfo-gateway] [*] 2d23h
现在我们再去访问 Bookinfo 应用又回到最初随机访问 Reviews 的情况了
来对 Reviews 服务添加一条路由规则,启用samples/bookinfo/networking/virtual-service-reviews-v1.yaml 定义的VirtualService
规则,内容如下:
cp samples/bookinfo/networking/virtual-service-reviews-v3.yaml samples/bookinfo/networking/virtual-service-reviews-v1.yaml
# cat samples/bookinfo/networking/virtual-service-reviews-v1.yaml apiVersion: networking.istio.io/v1alpha3 kind: VirtualService metadata: name: reviews spec: hosts: - reviews http: - route: - destination: host: reviews subset: v1 weight : 1
这样,所有访问 reviews 服务的流量就会被引导到 reviews 服务对应的 subset 为 v1的 Pod 中。启用这条规则:
[root@k8s-master istio-1.3.1]# kubectl apply -f samples/bookinfo/networking/virtual-service-reviews-v1.yaml virtualservice.networking.istio.io/reviews created [root@k8s-master istio-1.3.1]# kubectl get virtualservices NAME GATEWAYS HOSTS AGE bookinfo [bookinfo-gateway] [*] 2d23h reviews [reviews] 3s [root@k8s-master istio-1.3.1]#
DestinationRule
不用动
此时再访问应用就成功了,多次刷新页面发现 Reviews 都展示的是 v1 版本,没有星星的ratings