通过配置ASMHeaderPropagation实现宽松模式的流量泳道

前提条件

• 已创建ASM企业版或旗舰版实例，且实例版本为1.21.6.54及以上。具体操作，请参见创建ASM实例或升级ASM实例。

• 已添加Kubernetes集群到ASM实例。具体操作，请参见添加集群到ASM实例。

• 已创建名称为ingressgateway的ASM网关。具体操作，请参见创建入口网关。

功能介绍

Baggage是OpenTelemetry推出的一种标准化机制,旨在实现分布式系统调用链路中跨进程传递上下文信息。它通过在HTTP头部增加名为“Baggage”的字段实现，字段值为键值对格式，可传递租户ID、追踪ID、安全凭证等上下文数据，支持链路追踪、日志关联等功能而无需修改代码。例如：

baggage: userId=alice,serverNode=DF%2028,isProduction=false

基于透传的Baggage上下文信息，服务网格ASM可以利用ASMHeaderPropagation资源帮助您在服务调用链路上透传任意请求头、并基于该请求头实现宽松模式的流量泳道。有关宽松模式的流量泳道，请参见流量泳道概述。

步骤一：配置服务透传Baggage上下文

本节主要展示如何通过OpenTelemetry Operator自动插装的方法，为Kubernetes集群中的服务添加Baggage透传能力。

1. 部署OpenTelemetry Operator。

   1. 通过kubectl连接到ASM实例添加的Kubernetes集群。执行以下命令，创建opentelemetry-operator-system命名空间。

      kubectl create namespace opentelemetry-operator-system

   2. 执行以下命令，使用Helm在opentelemetry-operator-system命名空间下安装OpenTelemetry Operator。（关于Helm安装步骤，请参见安装Helm）

      helm repo add open-telemetry https://open-telemetry.github.io/opentelemetry-helm-charts
      helm install  \
          --namespace=opentelemetry-operator-system \
          --version=0.46.0 \
          --set admissionWebhooks.certManager.enabled=false \
          --set admissionWebhooks.certManager.autoGenerateCert=true \
          --set manager.image.repository="registry-cn-hangzhou.ack.aliyuncs.com/acs/opentelemetry-operator" \
          --set manager.image.tag="0.92.1" \
          --set kubeRBACProxy.image.repository="registry-cn-hangzhou.ack.aliyuncs.com/acs/kube-rbac-proxy" \
          --set kubeRBACProxy.image.tag="v0.13.1" \
          --set manager.collectorImage.repository="registry-cn-hangzhou.ack.aliyuncs.com/acs/opentelemetry-collector" \
          --set manager.collectorImage.tag="0.97.0" \
          --set manager.opampBridgeImage.repository="registry-cn-hangzhou.ack.aliyuncs.com/acs/operator-opamp-bridge" \
          --set manager.opampBridgeImage.tag="0.97.0" \
          --set manager.targetAllocatorImage.repository="registry-cn-hangzhou.ack.aliyuncs.com/acs/target-allocator" \
          --set manager.targetAllocatorImage.tag="0.97.0" \
          --set manager.autoInstrumentationImage.java.repository="registry-cn-hangzhou.ack.aliyuncs.com/acs/autoinstrumentation-java" \
          --set manager.autoInstrumentationImage.java.tag="1.32.1" \
          --set manager.autoInstrumentationImage.nodejs.repository="registry-cn-hangzhou.ack.aliyuncs.com/acs/autoinstrumentation-nodejs" \
          --set manager.autoInstrumentationImage.nodejs.tag="0.49.1" \
          --set manager.autoInstrumentationImage.python.repository="registry-cn-hangzhou.ack.aliyuncs.com/acs/autoinstrumentation-python" \
          --set manager.autoInstrumentationImage.python.tag="0.44b0" \
          --set manager.autoInstrumentationImage.dotnet.repository="registry-cn-hangzhou.ack.aliyuncs.com/acs/autoinstrumentation-dotnet" \
          --set manager.autoInstrumentationImage.dotnet.tag="1.2.0" \
          --set manager.autoInstrumentationImage.go.repository="registry-cn-hangzhou.ack.aliyuncs.com/acs/opentelemetry-go-instrumentation" \
          --set manager.autoInstrumentationImage.go.tag="v0.10.1.alpha-2-aliyun" \
          opentelemetry-operator open-telemetry/opentelemetry-operator

   3. 执行以下命令，检查opentelemetry-operator是否正常运行。

      kubectl get pod -n opentelemetry-operator-system

      预期输出：

      NAME                                      READY   STATUS    RESTARTS   AGE
      opentelemetry-operator-854fb558b5-pvllj   2/2     Running   0          1m

2. 配置自动插装（auto-instrumentation）。

   1. 使用以下内容，创建instrumentation.yaml文件。

      apiVersion: opentelemetry.io/v1alpha1
      kind: Instrumentation
      metadata:
        name: demo-instrumentation
      spec:
        propagators:
          - baggage
        sampler:
          type: parentbased_traceidratio
          argument: "1"

   2. 执行以下命令，在default命名空间下声明自动插装。

      kubectl apply -f instrumentation.yaml

      说明

      对于OpenTelemetry框架来说，其最佳实践还包括部署OpenTelemetry Collector以收集可观测数据。由于本文主要演示OpenTelemetry自动插装实现的Baggage链路透传，因此没有包含部署OpenTelemetry Collector的步骤。有关服务网格ASM如何通过OpenTelemetry上报链路追踪数据，请参考见将链路追踪数据采集到阿里云可观测链路OpenTelemetry版。

步骤二：部署示例服务

1. 为default命名空间启用Sidecar网格代理自动注入。具体操作，请参见管理全局命名空间。

   说明

   关于自动注入的更多信息，请参见配置Sidecar注入策略。

2. 使用以下内容，创建mock.yaml文件。

   展开查看mock.yaml内容

   apiVersion: v1
   kind: Service
   metadata:
     name: mocka
     labels:
       app: mocka
       service: mocka
   spec:
     ports:
     - port: 8000
       name: http
     selector:
       app: mocka
   ---
   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: mocka-v1
     labels:
       app: mocka
       version: v1
   spec:
     replicas: 1
     selector:
       matchLabels:
         app: mocka
         version: v1
         ASM_TRAFFIC_TAG: v1
     template:
       metadata:
         labels:
           app: mocka
           version: v1
           ASM_TRAFFIC_TAG: v1
         annotations:
           instrumentation.opentelemetry.io/inject-java: "true"
           instrumentation.opentelemetry.io/container-names: "default"
       spec:
         containers:
         - name: default
           image: registry-cn-hangzhou.ack.aliyuncs.com/acs/asm-mock:v0.1-java
           imagePullPolicy: IfNotPresent
           env:
           - name: version
             value: v1
           - name: app
             value: mocka
           - name: upstream_url
             value: "http://mockb:8000/"
           ports:
           - containerPort: 8000
   ---
   apiVersion: v1
   kind: Service
   metadata:
     name: mockb
     labels:
       app: mockb
       service: mockb
   spec:
     ports:
     - port: 8000
       name: http
     selector:
       app: mockb
   ---
   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: mockb-v1
     labels:
       app: mockb
       version: v1
   spec:
     replicas: 1
     selector:
       matchLabels:
         app: mockb
         version: v1
         ASM_TRAFFIC_TAG: v1
     template:
       metadata:
         labels:
           app: mockb
           version: v1
           ASM_TRAFFIC_TAG: v1
         annotations:
           instrumentation.opentelemetry.io/inject-java: "true"
           instrumentation.opentelemetry.io/container-names: "default"
       spec:
         containers:
         - name: default
           image: registry-cn-hangzhou.ack.aliyuncs.com/acs/asm-mock:v0.1-java
           imagePullPolicy: IfNotPresent
           env:
           - name: version
             value: v1
           - name: app
             value: mockb
           - name: upstream_url
             value: "http://mockc:8000/"
           ports:
           - containerPort: 8000
   
   ---
   apiVersion: v1
   kind: Service
   metadata:
     name: mockc
     labels:
       app: mockc
       service: mockc
   spec:
     ports:
     - port: 8000
       name: http
     selector:
       app: mockc
   ---
   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: mockc-v1
     labels:
       app: mockc
       version: v1
   spec:
     replicas: 1
     selector:
       matchLabels:
         app: mockc
         version: v1
         ASM_TRAFFIC_TAG: v1
     template:
       metadata:
         labels:
           app: mockc
           version: v1
           ASM_TRAFFIC_TAG: v1
         annotations:
           instrumentation.opentelemetry.io/inject-java: "true"
           instrumentation.opentelemetry.io/container-names: "default"
       spec:
         containers:
         - name: default
           image: registry-cn-hangzhou.ack.aliyuncs.com/acs/asm-mock:v0.1-java
           imagePullPolicy: IfNotPresent
           env:
           - name: version
             value: v1
           - name: app
             value: mockc
           ports:
           - containerPort: 8000
   ---
   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: mocka-v2
     labels:
       app: mocka
       version: v2
   spec:
     replicas: 1
     selector:
       matchLabels:
         app: mocka
         version: v2
         ASM_TRAFFIC_TAG: v2
     template:
       metadata:
         labels:
           app: mocka
           version: v2
           ASM_TRAFFIC_TAG: v2
         annotations:
           instrumentation.opentelemetry.io/inject-java: "true"
           instrumentation.opentelemetry.io/container-names: "default"
       spec:
         containers:
         - name: default
           image: registry-cn-hangzhou.ack.aliyuncs.com/acs/asm-mock:v0.1-java
           imagePullPolicy: IfNotPresent
           env:
           - name: version
             value: v2
           - name: app
             value: mocka
           - name: upstream_url
             value: "http://mockb:8000/"
           ports:
           - containerPort: 8000
   ---
   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: mockb-v2
     labels:
       app: mockb
       version: v2
   spec:
     replicas: 1
     selector:
       matchLabels:
         app: mockb
         version: v2
         ASM_TRAFFIC_TAG: v2
     template:
       metadata:
         labels:
           app: mockb
           version: v2
           ASM_TRAFFIC_TAG: v2
         annotations:
           instrumentation.opentelemetry.io/inject-java: "true"
           instrumentation.opentelemetry.io/container-names: "default"
       spec:
         containers:
         - name: default
           image: registry-cn-hangzhou.ack.aliyuncs.com/acs/asm-mock:v0.1-java
           imagePullPolicy: IfNotPresent
           env:
           - name: version
             value: v2
           - name: app
             value: mockb
           - name: upstream_url
             value: "http://mockc:8000/"
           ports:
           - containerPort: 8000
   
   ---
   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: mockc-v2
     labels:
       app: mockc
       version: v2
   spec:
     replicas: 1
     selector:
       matchLabels:
         app: mockc
         version: v2
         ASM_TRAFFIC_TAG: v2
     template:
       metadata:
         labels:
           app: mockc
           version: v2
           ASM_TRAFFIC_TAG: v2
         annotations:
           instrumentation.opentelemetry.io/inject-java: "true"
           instrumentation.opentelemetry.io/container-names: "default"
       spec:
         containers:
         - name: default
           image: registry-cn-hangzhou.ack.aliyuncs.com/acs/asm-mock:v0.1-java
           imagePullPolicy: IfNotPresent
           env:
           - name: version
             value: v2
           - name: app
             value: mockc
           ports:
           - containerPort: 8000
   ---
   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: mocka-v3
     labels:
       app: mocka
       version: v3
   spec:
     replicas: 1
     selector:
       matchLabels:
         app: mocka
         version: v3
         ASM_TRAFFIC_TAG: v3
     template:
       metadata:
         labels:
           app: mocka
           version: v3
           ASM_TRAFFIC_TAG: v3
         annotations:
           instrumentation.opentelemetry.io/inject-java: "true"
           instrumentation.opentelemetry.io/container-names: "default"
       spec:
         containers:
         - name: default
           image: registry-cn-hangzhou.ack.aliyuncs.com/acs/asm-mock:v0.1-java
           imagePullPolicy: IfNotPresent
           env:
           - name: version
             value: v3
           - name: app
             value: mocka
           - name: upstream_url
             value: "http://mockb:8000/"
           ports:
           - containerPort: 8000
   ---
   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: mockb-v3
     labels:
       app: mockb
       version: v3
   spec:
     replicas: 1
     selector:
       matchLabels:
         app: mockb
         version: v3
         ASM_TRAFFIC_TAG: v3
     template:
       metadata:
         labels:
           app: mockb
           version: v3
           ASM_TRAFFIC_TAG: v3
         annotations:
           instrumentation.opentelemetry.io/inject-java: "true"
           instrumentation.opentelemetry.io/container-names: "default"
       spec:
         containers:
         - name: default
           image: registry-cn-hangzhou.ack.aliyuncs.com/acs/asm-mock:v0.1-java
           imagePullPolicy: IfNotPresent
           env:
           - name: version
             value: v3
           - name: app
             value: mockb
           - name: upstream_url
             value: "http://mockc:8000/"
           ports:
           - containerPort: 8000
   
   ---
   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: mockc-v3
     labels:
       app: mockc
       version: v3
   spec:
     replicas: 1
     selector:
       matchLabels:
         app: mockc
         version: v3
         ASM_TRAFFIC_TAG: v3
     template:
       metadata:
         labels:
           app: mockc
           version: v3
           ASM_TRAFFIC_TAG: v3
         annotations:
           instrumentation.opentelemetry.io/inject-java: "true"
           instrumentation.opentelemetry.io/container-names: "default"
       spec:
         containers:
         - name: default
           image: registry-cn-hangzhou.ack.aliyuncs.com/acs/asm-mock:v0.1-java
           imagePullPolicy: IfNotPresent
           env:
           - name: version
             value: v3
           - name: app
             value: mockc
           ports:
           - containerPort: 8000

   对于每个实例服务Pod，都加入了instrumentation.opentelemetry.io/inject-java: "true"和instrumentation.opentelemetry.io/container-names: "default"两个注解，以声明该实例服务使用Java语言实现，并要求OpenTelemetry Operator对名称为default的容器进行自动插装。

3. 执行以下命令，部署实例服务。

   kubectl apply -f mock.yaml

   基于OpenTelemetry自动插装机制，部署的服务Pod将自动具有在调用链路中传递Baggage的能力。

步骤三：创建流量规则实现宽松模式流量泳道

1. 创建DestinationRule流量规则。

   1. 使用以下内容，创建dr-mock.yaml文件。

      展开查看YAML内容

      apiVersion: networking.istio.io/v1beta1
      kind: DestinationRule
      metadata:
        name: dr-mock-default-mocka
      spec:
        host: mocka.default.svc.cluster.local
        subsets:
          - labels:
              version: v1
            name: v1
          - labels:
              version: v2
            name: v2
          - labels:
              version: v3
            name: v3
      ---
      apiVersion: networking.istio.io/v1beta1
      kind: DestinationRule
      metadata:
        name: dr-mock-default-mockb
      spec:
        host: mockb.default.svc.cluster.local
        subsets:
          - labels:
              version: v1
            name: v1
          - labels:
              version: v3
            name: v3
      ---
      apiVersion: networking.istio.io/v1beta1
      kind: DestinationRule
      metadata:
        name: dr-mock-default-mockc
      spec:
        host: mockc.default.svc.cluster.local
        subsets:
          - labels:
              version: v1
            name: v1
          - labels:
              version: v2
            name: v2

      此文件表示将mocka、mockb、mockc三个服务按照Pod的version标签分为v1、v2、v3三个版本子集，其中mocka有v1、v2、v3三个版本，mockb有v1、v3两个版本，mockc有v1、v2两个版本。

   2. 通过kubectl连接ASM实例，执行以下命令，创建DestinationRule流量规则。

      kuebctl apply -f dr-mock.yaml

2. 创建ASMHeaderPropagation流量规则。服务已经实现了Baggage透传能力的前提下，可以通过ASMHeaderPropagation流量规则来指定利用Baggage在链路上透传自定义请求头。

   1. 使用以下内容，创建propagation.yaml文件。以下文件表示利用Baggage中的上下文信息，在调用链路中透传名为version的请求头。

      apiVersion: istio.alibabacloud.com/v1beta1
      kind: ASMHeaderPropagation
      metadata:
        name: version-propagation
      spec:
        headers:
          - version

   2. 通过kubectl连接ASM实例，执行以下命令， 创建ASMHeaderPropagation流量规则。

      kuebctl apply -f propagation.yaml

3. 创建VirtualService流量规则。

   1. 使用以下内容，创建vs-mock.yaml文件。

      展开查看YAML内容

      apiVersion: networking.istio.io/v1beta1
      kind: VirtualService
      metadata:
        name: vs-mock-default-mocka
      spec:
        hosts:
          - mocka.default.svc.cluster.local
        http:
          - match:
              - headers:
                  version:
                    exact: v1
            route:
              - destination:
                  host: mocka.default.svc.cluster.local
                  subset: v1
                fallback:
                  target:
                    host: mocka.default.svc.cluster.local
                    subset: v1
          - match:
              - headers:
                  version:
                    exact: v2
            route:
              - destination:
                  host: mocka.default.svc.cluster.local
                  subset: v2
                fallback:
                  target:
                    host: mocka.default.svc.cluster.local
                    subset: v1
          - match:
              - headers:
                  version:
                    exact: v3
            route:
              - destination:
                  host: mocka.default.svc.cluster.local
                  subset: v3
                fallback:
                  target:
                    host: mocka.default.svc.cluster.local
                    subset: v1
      ---
      apiVersion: networking.istio.io/v1beta1
      kind: VirtualService
      metadata:
        name: vs-mock-default-mockb
      spec:
        hosts:
          - mockb.default.svc.cluster.local
        http:
          - match:
              - headers:
                  version:
                    exact: v1
            route:
              - destination:
                  host: mockb.default.svc.cluster.local
                  subset: v1
                fallback:
                  target:
                    host: mockb.default.svc.cluster.local
                    subset: v1
          - match:
              - headers:
                  version:
                    exact: v2
            route:
              - destination:
                  host: mockb.default.svc.cluster.local
                  subset: v2
                fallback:
                  target:
                    host: mockb.default.svc.cluster.local
                    subset: v1
          - match:
              - headers:
                  version:
                    exact: v3
            route:
              - destination:
                  host: mockb.default.svc.cluster.local
                  subset: v3
                fallback:
                  target:
                    host: mockb.default.svc.cluster.local
                    subset: v1
      ---
      apiVersion: networking.istio.io/v1beta1
      kind: VirtualService
      metadata:
        name: vs-mock-default-mockc
      spec:
        hosts:
          - mockc.default.svc.cluster.local
        http:
          - match:
              - headers:
                  version:
                    exact: v1
            route:
              - destination:
                  host: mockc.default.svc.cluster.local
                  subset: v1
                fallback:
                  target:
                    host: mockc.default.svc.cluster.local
                    subset: v1
          - match:
              - headers:
                  version:
                    exact: v2
            route:
              - destination:
                  host: mockc.default.svc.cluster.local
                  subset: v2
                fallback:
                  target:
                    host: mockc.default.svc.cluster.local
                    subset: v1
          - match:
              - headers:
                  version:
                    exact: v3
            route:
              - destination:
                  host: mockc.default.svc.cluster.local
                  subset: v3
                fallback:
                  target:
                    host: mockc.default.svc.cluster.local
                    subset: v1
      

      此文件为mocka→mockb→mockc的服务调用链路创建流量泳道路由规则。具体来说，是通过匹配调用链路中透传的version请求头内容、将请求转发到对应的版本（例如，带有version: v2请求头的请求都发送到v2版本的服务）。同时，该流量规则也指定了流量回退规则：当调用链路中的某个服务的对应版本不存在时，统一将请求回退到服务的v1版本。

   2. 通过kubectl连接ASM实例，执行以下命令，创建VirtualService流量规则。

      kubectl apply -f vs-mock.yaml

4. 创建网关引流规则。

   1. 使用以下内容，创建gw-mock.yaml文件。

      展开查看YAML内容

      apiVersion: networking.istio.io/v1beta1
      kind: Gateway
      metadata:
        name: mockgw
        namespace: default
      spec:
        selector:
          istio: ingressgateway
        servers:
          - hosts:
              - '*'
            port:
              name: http
              number: 80
              protocol: HTTP
      ---
      apiVersion: networking.istio.io/v1beta1
      kind: VirtualService
      metadata:
        name: swimlane-ingress-vs-weighted-mock
        namespace: default
      spec:
        gateways:
          - default/mockgw
        hosts:
          - '*'
        http:
          - name: mock-weighted
            route:
              - destination:
                  host: mocka.default.svc.cluster.local
                  subset: v1
                headers:
                  request:
                    set:
                      version: v1
                weight: 40
              - destination:
                  host: mocka.default.svc.cluster.local
                  subset: v2
                headers:
                  request:
                    set:
                      version: v2
                weight: 30
              - destination:
                  host: mocka.default.svc.cluster.local
                  subset: v3
                headers:
                  request:
                    set:
                      version: v3
                weight: 30

      此文件表示为mocka→mockb→mockc的服务调用链路创建网关引流规则。引流方式则为权重引流，对于发送到ASM网关的流量，以4:3:3的比例分别转发到mocka服务的v1、v2、v3版本。当网关向mocka服务转发请求时，会根据转发的目标版本为请求添加version请求头，保证调用链路中存在泳道对应的版本信息。

   2. 通过kubectl连接ASM实例，执行以下命令，创建网关引流规则。

      kubectl apply -f gw-mock.yaml

步骤四：验证流量泳道是否生效

1. 获取ASM网关的公网IP。具体操作，请参见步骤二：获取ASM网关地址。

2. 执行以下命令，设置环境变量。xxx.xxx.xxx.xxx为上一步获取的IP。

   export ASM_GATEWAY_IP=xxx.xxx.xxx.xxx

3. 验证全灰度链路功能是否生效。

   1. 执行以下命令，查看v1泳道的访问效果。

      for i in {1..100};  do curl http://${ASM_GATEWAY_IP} ;  echo ''; sleep 1; done;

      预期输出：

      -> mocka(version: v1, ip: 192.168.1.27)-> mockb(version: v1, ip: 192.168.1.30)-> mockc(version: v1, ip: 192.168.1.14)
      -> mocka(version: v1, ip: 192.168.1.27)-> mockb(version: v1, ip: 192.168.1.30)-> mockc(version: v1, ip: 192.168.1.14)
      -> mocka(version: v2, ip: 192.168.1.28)-> mockb(version: v1, ip: 192.168.1.30)-> mockc(version: v2, ip: 192.168.1.1)
      -> mocka(version: v3, ip: 192.168.1.26)-> mockb(version: v3, ip: 192.168.1.29)-> mockc(version: v1, ip: 192.168.1.14)
      -> mocka(version: v1, ip: 192.168.1.27)-> mockb(version: v1, ip: 192.168.1.30)-> mockc(version: v1, ip: 192.168.1.14)
      -> mocka(version: v1, ip: 192.168.1.27)-> mockb(version: v1, ip: 192.168.1.30)-> mockc(version: v1, ip: 192.168.1.14)
      -> mocka(version: v2, ip: 192.168.1.28)-> mockb(version: v1, ip: 192.168.1.30)-> mockc(version: v2, ip: 192.168.1.1)
      -> mocka(version: v2, ip: 192.168.1.28)-> mockb(version: v1, ip: 192.168.1.30)-> mockc(version: v2, ip: 192.168.1.1)
      -> mocka(version: v2, ip: 192.168.1.28)-> mockb(version: v1, ip: 192.168.1.30)-> mockc(version: v2, ip: 192.168.1.1)
      -> mocka(version: v2, ip: 192.168.1.28)-> mockb(version: v1, ip: 192.168.1.30)-> mockc(version: v2, ip: 192.168.1.1)
      -> mocka(version: v3, ip: 192.168.1.26)-> mockb(version: v3, ip: 192.168.1.29)-> mockc(version: v1, ip: 192.168.1.14)
      -> mocka(version: v1, ip: 192.168.1.27)-> mockb(version: v1, ip: 192.168.1.30)-> mockc(version: v1, ip: 192.168.1.14)
      -> mocka(version: v2, ip: 192.168.1.28)-> mockb(version: v1, ip: 192.168.1.30)-> mockc(version: v2, ip: 192.168.1.1)
      -> mocka(version: v3, ip: 192.168.1.26)-> mockb(version: v3, ip: 192.168.1.29)-> mockc(version: v1, ip: 192.168.1.14)
      -> mocka(version: v1, ip: 192.168.1.27)-> mockb(version: v1, ip: 192.168.1.30)-> mockc(version: v1, ip: 192.168.1.14)
      -> mocka(version: v3, ip: 192.168.1.26)-> mockb(version: v3, ip: 192.168.1.29)-> mockc(version: v1, ip: 192.168.1.14)
      -> mocka(version: v3, ip: 192.168.1.26)-> mockb(version: v3, ip: 192.168.1.29)-> mockc(version: v1, ip: 192.168.1.14)
      -> mocka(version: v1, ip: 192.168.1.27)-> mockb(version: v1, ip: 192.168.1.30)-> mockc(version: v1, ip: 192.168.1.14)
      -> mocka(version: v3, ip: 192.168.1.26)-> mockb(version: v3, ip: 192.168.1.29)-> mockc(version: v1, ip: 192.168.1.14)
      -> mocka(version: v2, ip: 192.168.1.28)-> mockb(version: v1, ip: 192.168.1.30)-> mockc(version: v2, ip: 192.168.1.1)
      -> mocka(version: v1, ip: 192.168.1.27)-> mockb(version: v1, ip: 192.168.1.30)-> mockc(version: v1, ip: 192.168.1.14)
      -> mocka(version: v3, ip: 192.168.1.26)-> mockb(version: v3, ip: 192.168.1.29)-> mockc(version: v1, ip: 192.168.1.14)
      -> mocka(version: v1, ip: 192.168.1.27)-> mockb(version: v1, ip: 192.168.1.30)-> mockc(version: v1, ip: 192.168.1.14)
      -> mocka(version: v3, ip: 192.168.1.26)-> mockb(version: v3, ip: 192.168.1.29)-> mockc(version: v1, ip: 192.168.1.14)

      可以看到，流量将以约4:3:3的比例发送到服务调用链路的v1、v2、v3三个版本，并由v1作为基线版本，当调用链路中不存在某个服务的特定版本时，将会调用该服务的v1版本。