流量管理

在本节中，我们将延续上一个任务【在 Istio 环境部署 Dubbo-go 应用】。

在之前的任务中，我们在集群中部署了一组 Dubbo-go Server和 Client 端应用，验证了服务发现和调用成功。在本节中，我们将创建新版本的 Server 端应用。通过配置 VirtualService 和 DestinationRule ，实现路由管理，和流量转移能力

1. 准备工作

• dubbo-go cli 工具和依赖工具已安装、grpc_cli (如需本地调试)。
• docker、helm、kubectl 环境已安装。（arm 机器需支持 docker buildx）
• 任务【在 Istio 环境部署 Dubbo-go 应用】已完成

2. 开发多版本Dubbo-go 应用。

2.1 使用 dubbogo-cli 创建另一个项目模板

$ dubbogo-cli newApp .

2.2 开发和部署客户端 Dubbo-go 应用 v2：

编写业务逻辑

• 修改 package/service/service.go 的实现方法，返回版本号为 v2.0.0

func (s *GreeterServerImpl) SayHello(ctx context.Context, in *api.HelloRequest) (*api.User, error) {
    return &api.User{Name: "Hello " + in.Name, Id: "v2.0.0"}, nil
}

• 修改如下配置文件，使用xds协议作为注册中心，加载名为 GreeterServerImpl 的服务结构。

  conf/dubbogo.yaml

  dubbo:
    registries:
      xds:
        protocol: xds
        address: istiod.istio-system.svc.cluster.local:15010
    protocols:
      triple:
        name: tri
        port: 20000
    provider:
      services:
        GreeterServerImpl:
          interface: "" # read from stub

  至此，应用开发完成。

配置构建和部署参数

• 指定需要构建的镜像：

  修改 Makefile 如下字段，指定好需要构建的镜像地址和版本，我们把镜像 tag 改为 2.0.0。

  指定好需要通过 helm 安装的名称。

  IMAGE = xxx/dubbo-go-server
  TAG = 2.0.0
  HELM_INSTALL_NAME = dubbo-go-server

• 指定需要部署的应用和镜像：

  修改 chart/app/Chart.yaml 如下字段，指定当前应用名为 dubbo-go-server，我们在创建v1版本服务的时候，已经有了该应用的 service，这次部署时模板将不会创建 service。

  apiVersion: v1
  name: dubbo-go-server
  description: dubbo-go-server

  修改 chart/app/values.yaml 如下字段，指定需要部署的镜像为2.0.0，以及当前开发的应用版本 dubbogoAppVersion 为 v2。

  部署的镜像需要和上述构建的镜像一致。当前应用版本用于 mesh 流量规则控制。

  image:
    repository:  xxx/dubbo-go-server
    pullPolicy: Always
    tag: "2.0.0"
  # Dubbo-go-mesh version control labels
  version:
    labels:
      dubbogoAppVersion: v2

  至此，构建参数和发布参数都已指定好，可以进行构建和部署了。

使用模板构建和部署 Dubbo-go 应用

• 构建、推送镜像

  $ make build (本地为 amd64机器)

  或者

  $ make buildx-publish (本地为 arm64机器，依赖 docker buildx 命令)

• 发布 Dubbo-go Server v2 至集群

  $ make deploy
  NAME: dubbo-go-server-v2
  LAST DEPLOYED: Thu Apr  7 12:29:28 2022
  NAMESPACE: default
  STATUS: deployed
  REVISION: 1
  TEST SUITE: None
  $ helm list
  NAME                    NAMESPACE       REVISION        UPDATED                                 STATUS          CHART                   dubbo-go-client         default         1               2022-04-07 11:49:55.517898 +0800 CST    deployed        dubbo-go-client-0.0.1   1.16.0     
  dubbo-go-server-v1      default         1               2022-04-07 11:23:18.397658 +0800 CST    deployed        dubbo-go-server-0.0.1   1.16.0     
  dubbo-go-server-v2      default         1               2022-04-07 12:29:28.497476 +0800 CST    deployed        dubbo-go-client-0.0.1   1.16.0

  可看到通过 helm 部署成功, 目前已经在集群中存在一个 Client 应用，和 Server 的两个版本。

2.3 验证应用

查看资源部署情况

查看部署好的 deployment ，server 包含了两个版本。

$  kubectl get deployment 
NAME                 READY   UP-TO-DATE   AVAILABLE   AGE
dubbo-go-client-v1   1/1     1            1           40m
dubbo-go-server-v2   1/1     1            1           77s
dubbo-go-server-v1   1/1     1            1           67m

查看部署好的 service。两个版本的deployment 共用同一个 service。

$ kubectl get svc        
NAME              TYPE        CLUSTER-IP        EXTERNAL-IP   PORT(S)     AGE
dubbo-go-client   ClusterIP   192.168.8.176     <none>        20000/TCP   41m
dubbo-go-server   ClusterIP   192.168.216.253   <none>        20000/TCP   67m

查看 Client 应用日志，验证请求调用到了两个版本的应用上。

$ kubectl get pods  | grep client | awk '{print $1}' | xargs kubectl logs 
...
2022-04-07T05:06:40.384Z        INFO    cmd/app.go:29   call server response = name:"Hello laurence" id:"v2.0.0"
2022-04-07T05:06:41.386Z        INFO    cmd/app.go:29   call server response = name:"Hello laurence" id:"v2.0.0"
2022-04-07T05:06:42.388Z        INFO    cmd/app.go:29   call server response = name:"Hello laurence" id:"v1.0.0"
2022-04-07T05:06:43.389Z        INFO    cmd/app.go:29   call server response = name:"Hello laurence" id:"v2.0.0"
2022-04-07T05:06:44.390Z        INFO    cmd/app.go:29   call server response = name:"Hello laurence" id:"v2.0.0"
2022-04-07T05:06:45.392Z        INFO    cmd/app.go:29   call server response = name:"Hello laurence" id:"v1.0.0"
2022-04-07T05:06:46.393Z        INFO    cmd/app.go:29   call server response = name:"Hello laurence" id:"v1.0.0"
2022-04-07T05:06:47.394Z        INFO    cmd/app.go:29   call server response = name:"Hello laurence" id:"v1.0.0"
2022-04-07T05:06:48.396Z        INFO    cmd/app.go:29   call server response = name:"Hello laurence" id:"v2.0.0"
2022-04-07T05:06:49.397Z        INFO    cmd/app.go:29   call server response = name:"Hello laurence" id:"v1.0.0"

至此，我们开发并且部署成功了多版本应用。

3. 配置请求路由

3.1 配置目标规则

执行以下命令以创建目标规则，该目标规则将 dubbo-go-server 细分为两个子集。v1和 v2

$ kubectl apply -f destinationrule.yaml

destinationrule.yaml 内容：

apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: dubbo-go-server
spec:
  host: dubbo-go-server
  subsets:
    - name: v1
      labels:
        dubbogoAppVersion: v1 # 对应应用模板中 chart/app/values.yaml 中指定的版本标签
    - name: v2
      labels:
        dubbogoAppVersion: v2

3.2 应用 Virtual Service

执行以下命令以创建路由，该路由将所有流量都路由至v1 版本应用。

$ kubectl apply -f virtualservice.yaml

virtualservice.yaml 内容

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: dubbo-go-server
spec:
  hosts:
    - dubbo-go-server
  http:
  - route:
    - destination:
        host: dubbo-go-server
        subset: v1

3.3 验证路由生效

所有流量将流向 v1 版本应用。

$ kubectl get pods  | grep client | awk '{print $1}' | xargs kubectl logs 
...
2022-04-07T05:40:44.353Z        INFO    cmd/app.go:29   call server response = name:"Hello laurence" id:"v1.0.0"
2022-04-07T05:40:45.354Z        INFO    cmd/app.go:29   call server response = name:"Hello laurence" id:"v1.0.0"
2022-04-07T05:40:46.356Z        INFO    cmd/app.go:29   call server response = name:"Hello laurence" id:"v1.0.0"
2022-04-07T05:40:47.357Z        INFO    cmd/app.go:29   call server response = name:"Hello laurence" id:"v1.0.0"
2022-04-07T05:40:48.359Z        INFO    cmd/app.go:29   call server response = name:"Hello laurence" id:"v1.0.0"
2022-04-07T05:40:49.361Z        INFO    cmd/app.go:29   call server response = name:"Hello laurence" id:"v1.0.0"

4. 基于用户身份的路由

有了上述多版本应用路由的基础，我们可以通过一些策略，来进行灵活的流量管理。

4.1 为客户端应用增加用户身份标识

我们希望拥有 user: admin 标识的流量都可以体验 v2 新版本应用。

回到之前创建的 dubbo-go-client 项目，修改 cmd/app.go 的 main 函数，增加调用标识：user: admin。

func main() {
    client := &api.GreeterClientImpl{}
    config.SetConsumerService(client)
    if err := config.Load(); err != nil {
        panic(err)
    }
    request := &api.HelloRequest{
        Name: "laurence",
    }
    for{
        ctx := context.Background()
        ctx = context.WithValue(ctx, constant.AttachmentKey, map[string]string{ 
            "user":"admin", // 使用上下文 context 为调用增加标识
        })
        if rsp, err := client.SayHello(ctx, request); err != nil{
            logger.Errorf("call server error = %s", err)
        }else{
            logger.Infof("call server response = %+v", rsp)
        }
        time.Sleep(time.Second)
    }
}

• 构建、推送镜像，覆盖之前的提交。您也可以升级一下发布的镜像版本。

  $ make build (本地为 amd64机器)

  或者

  $ make buildx-publish (本地为 arm64机器，依赖 docker buildx 命令)

• 删除 dubbo-go-client 应用

  $ make remove
  helm uninstall dubbo-go-client
  release "dubbo-go-client" uninstalled

• 重新发布应用。

  $ make deploy

  发布后，验证调用成功，由于前面进行了路由配置。所有流量都流向 v1 版本。

  $ kubectl get pods  | grep client | awk '{print $1}' | xargs kubectl logs 
  ...
  2022-04-07T05:40:44.353Z        INFO    cmd/app.go:29   call server response = name:"Hello laurence" id:"v1.0.0"
  2022-04-07T05:40:45.354Z        INFO    cmd/app.go:29   call server response = name:"Hello laurence" id:"v1.0.0"
  2022-04-07T05:40:46.356Z        INFO    cmd/app.go:29   call server response = name:"Hello laurence" id:"v1.0.0"
  2022-04-07T05:40:47.357Z        INFO    cmd/app.go:29   call server response = name:"Hello laurence" id:"v1.0.0"
  2022-04-07T05:40:48.359Z        INFO    cmd/app.go:29   call server response = name:"Hello laurence" id:"v1.0.0"
  2022-04-07T05:40:49.361Z        INFO    cmd/app.go:29   call server response = name:"Hello laurence" id:"v1.0.0"

4.2 创建基于用户身份的路由

执行以下命令以修改/创建路由，该路由将所有请求头存在 user: admin 标识的流量都路由至 v2 版本。

$ kubectl apply -f virtualservice.yaml

virtualservice.yaml 内容

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: dubbo-go-server
spec:
  hosts:
    - dubbo-go-server
  http:
  - match:
    - headers:
        user:
          exact: admin
    route:
      - destination:
          host: dubbo-go-server
          subset: v2
  - route:
    - destination:
        host: dubbo-go-server
        subset: v1

4.3 验证路由生效

所有流量将流向 v2 版本应用。

$ kubectl get pods  | grep client | awk '{print $1}' | xargs kubectl logs 
...
2022-04-07T05:52:18.714Z        INFO    cmd/app.go:35   call server response = name:"Hello laurence"  id:"v2.0.0"
2022-04-07T05:52:19.716Z        INFO    cmd/app.go:35   call server response = name:"Hello laurence"  id:"v2.0.0"
2022-04-07T05:52:20.717Z        INFO    cmd/app.go:35   call server response = name:"Hello laurence"  id:"v2.0.0"
2022-04-07T05:52:21.718Z        INFO    cmd/app.go:35   call server response = name:"Hello laurence"  id:"v2.0.0"
2022-04-07T05:52:22.720Z        INFO    cmd/app.go:35   call server response = name:"Hello laurence"  id:"v2.0.0"
2022-04-07T05:52:23.722Z        INFO    cmd/app.go:35   call server response = name:"Hello laurence"  id:"v2.0.0"
2022-04-07T05:52:24.723Z        INFO    cmd/app.go:35   call server response = name:"Hello laurence"  id:"v2.0.0"

5. 基于权重的路由

5.1 创建基于权重的路由

延续上述任务，我们执行以下命令以修改/创建路由，该路由将流量的 10% 导入新版本应用，进行灰度测试。

$ kubectl apply -f virtualservice.yaml

virtualservice.yaml 内容

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: dubbo-go-server
spec:
  hosts:
    - dubbo-go-server
  http:
    - route:
      - destination:
          host: dubbo-go-server
          subset: v1
        weight: 90
      - destination:
          host: dubbo-go-server
          subset: v2
        weight: 10

5.2 验证路由生效

少数流量将流向 v2 版本。

$ kubectl get pods  | grep client | awk '{print $1}' | xargs kubectl logs 
...
2022-04-07T05:55:52.035Z        INFO    cmd/app.go:35   call server response = name:"Hello laurence"  id:"v1.0.0"
2022-04-07T05:55:53.036Z        INFO    cmd/app.go:35   call server response = name:"Hello laurence"  id:"v1.0.0"
2022-04-07T05:55:54.037Z        INFO    cmd/app.go:35   call server response = name:"Hello laurence"  id:"v1.0.0"
2022-04-07T05:55:55.039Z        INFO    cmd/app.go:35   call server response = name:"Hello laurence"  id:"v1.0.0"
2022-04-07T05:55:56.041Z        INFO    cmd/app.go:35   call server response = name:"Hello laurence"  id:"v1.0.0"
2022-04-07T05:55:57.043Z        INFO    cmd/app.go:35   call server response = name:"Hello laurence"  id:"v1.0.0"
2022-04-07T05:55:58.045Z        INFO    cmd/app.go:35   call server response = name:"Hello laurence"  id:"v1.0.0"
2022-04-07T05:55:59.047Z        INFO    cmd/app.go:35   call server response = name:"Hello laurence"  id:"v1.0.0"
2022-04-07T05:56:00.049Z        INFO    cmd/app.go:35   call server response = name:"Hello laurence"  id:"v1.0.0"
2022-04-07T05:56:01.050Z        INFO    cmd/app.go:35   call server response = name:"Hello laurence"  id:"v2.0.0"
2022-04-07T05:56:02.053Z        INFO    cmd/app.go:35   call server response = name:"Hello laurence"  id:"v1.0.0"
2022-04-07T05:56:03.055Z        INFO    cmd/app.go:35   call server response = name:"Hello laurence"  id:"v1.0.0"

最后修改 December 16, 2022: Fix check (#1736) (97972c1)