10个 Istio 流量管理 最常用的例子，你知道几个？

10 个 Istio 流量管理 最常用的例子，强烈建议收藏起来，以备不时之需。

为了方便理解，以Istio官方提供的Bookinfo应用示例为例，引出 Istio 流量管理的常用例子。

Bookinfo应用的架构图如下：

其中，包含四个单独的微服务：

• productpage：调用 details 和 reviews 两个服务，用来生成页面。
• details：包含了书籍的信息。
• reviews：包含了书籍相关的评论。它还会调用 ratings 微服务。
• rating：包含了由书籍评价组成的评级信息。

其中，reviews 服务有 3 个版本：

• v1 版本不会调用 ratings 服务。
• v2 版本会调用 ratings 服务，并使用 1 到 5 个黑色星形图标来显示评分信息。
• v3 版本会调用 ratings 服务，并使用 1 到 5 个红色星形图标来显示评分信息。

流量转移

目标1：把reviews 服务的所有流量都路由到v1版本。

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: reviews
spec:
  hosts:
  - reviews
  http:
  - route:
    - destination:
        host: reviews
        subset: v1
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: reviews
spec:
  host: reviews
  subsets:
    - labels:
        version: v1
      name: v1
    - labels:
        version: v2
      name: v2
    - labels:
        version: v3
      name: v3
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目标2：把reviews 服务的50%流量转移到v3版本。

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: reviews
spec:
  hosts:
    - reviews
  http:
  - route:
    - destination:
        host: reviews
        subset: v1
      weight: 50
    - destination:
        host: reviews
        subset: v3
      weight: 50
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: reviews
spec:
  host: reviews
  subsets:
    - labels:
        version: v1
      name: v1
    - labels:
        version: v2
      name: v2
    - labels:
        version: v3
      name: v3
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目标3：把reviews 服务的所有流量都路由到v3版本。

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: reviews
spec:
  hosts:
  - reviews
  http:
  - route:
    - destination:
        host: reviews
        subset: v3
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: reviews
spec:
  host: reviews
  subsets:
    - labels:
        version: v1
      name: v1
    - labels:
        version: v2
      name: v2
    - labels:
        version: v3
      name: v3
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基于用户身份的路由

目标：来自名为 OneMore 的用户的所有流量都路由到v2版本，其他流量都路由到v1版本。

Istio 对用户身份没有任何特殊的内置机制。在应用示例中，productpage服务在所有到 reviews 服务的 HTTP 请求中都增加了一个自定义的 end-user 请求头，其值为用户名。

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: reviews
spec:
  hosts:
    - reviews
  http:
  - match:
    - headers:
        end-user:
          exact: OneMore
    route:
    - destination:
        host: reviews
        subset: v2
  - route:
    - destination:
        host: reviews
        subset: v1
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: reviews
spec:
  host: reviews
  subsets:
    - labels:
        version: v1
      name: v1
    - labels:
        version: v2
      name: v2
    - labels:
        version: v3
      name: v3
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注入 HTTP 延迟故障

目标：用户 OneMore 访问时， ratings 服务注入一个 2 秒的延迟，productpage页面在大约 2 秒钟加载完成并且没有错误。

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: ratings
spec:
  hosts:
  - ratings
  http:
  - match:
    - headers:
        end-user:
          exact: OneMore
    fault:
      delay:
        percentage:
          value: 100.0
        fixedDelay: 2s
    route:
    - destination:
        host: ratings
        subset: v1
  - route:
    - destination:
        host: ratings
        subset: v1
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: ratings
spec:
  host: ratings
  subsets:
    - labels:
        version: v1
      name: v1
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注入 HTTP 中止故障

目标：用户 OneMore 访问时， ratings 服务注入一个503的中止故障，productpage 页面能够立即被加载，同时显示 “Ratings service is currently unavailable” 这样的消息。

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: ratings
spec:
  hosts:
    - ratings
  http:
    - fault:
        abort:
          httpStatus: 503
          percentage:
            value: 100
      match:
        - headers:
            end-user:
              exact: OneMore
      route:
        - destination:
            host: ratings
            subset: v1
    - route:
        - destination:
            host: ratings
            subset: v1
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: ratings
spec:
  host: ratings
  subsets:
    - labels:
        version: v1
      name: v1
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设置请求超时

首先，用户 OneMore 访问时， ratings 服务注入一个 2 秒的延迟，productpage页面在大约 2 秒钟加载完成并且没有错误。

按照上文注入 HTTP 延迟故障进行操作，不再赘述。

目标：用户 OneMore 访问时， reviews 服务的请求超时设置为 1 秒，同时显示 “Sorry, product reviews are currently unavailable for this book.” 这样的消息。

kind: VirtualService
apiVersion: networking.istio.io/v1alpha3
metadata:
  name: reviews
spec:
  hosts:
    - reviews
  http:
    - match:
        - headers:
            end-user:
              exact: OneMore
      route:
        - destination:
            host: reviews
            subset: v2
      timeout: 1s
    - route:
        - destination:
            host: reviews
            subset: v1
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: reviews
spec:
  host: reviews
  subsets:
    - labels:
        version: v1
      name: v1
    - labels:
        version: v2
      name: v2
    - labels:
        version: v3
      name: v3
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在Jaeger可以看到具体的调用链如下：

设置请求重试

首先，用户 OneMore 访问时， ratings 服务注入一个 2 秒的延迟，productpage页面在大约 2 秒钟加载完成并且没有错误。

按照上文注入 HTTP 延迟故障进行操作，不再赘述。

目标：用户 OneMore 访问时， reviews 服务的请求重试次数为2次，重试超时时间为 0.5 秒，同时显示 “Sorry, product reviews are currently unavailable for this book.” 这样的错误消息。

kind: VirtualService
apiVersion: networking.istio.io/v1alpha3
metadata:
  name: reviews
spec:
  hosts:
    - reviews
  http:
    - match:
        - headers:
            end-user:
              exact: OneMore
      route:
        - destination:
            host: reviews
            subset: v2
      retries:
        attempts: 2
        perTryTimeout: 0.5s
    - route:
        - destination:
            host: reviews
            subset: v1
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: reviews
spec:
  host: reviews
  subsets:
    - labels:
        version: v1
      name: v1
    - labels:
        version: v2
      name: v2
    - labels:
        version: v3
      name: v3
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拒绝目标IP的请求

目标：除了IP为10.201.240.131的客户端可以访问/api/v1/products/1，其他客户端拒绝请求。

apiVersion: security.istio.io/v1beta1
kind: AuthorizationPolicy
metadata:
  name: deny-by-ip
spec:
  selector:
    matchLabels:
      app: productpage
  action: DENY
  rules:
  - to:
    - operation:
        paths: ["/api/v1/products/1"]
    when:
    - key: remote.ip
      notValues: ["10.201.240.131"]
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熔断

目标：设置details服务的并发上限为1。

apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: details
spec:
  host: details
  trafficPolicy:
    connectionPool:
      tcp:
        maxConnections: 1
      http:
        http1MaxPendingRequests: 1
        maxRequestsPerConnection: 1
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可以使用 Fortio 进行负载测试，发送并发数为 2 的连接（-c 2），请求 20 次（-n 20）：

kubectl exec fortio-deploy-684b6b47f8-tzsg8 -c fortio -- /usr/bin/fortio load -c 3 -qps 0 -n 20 -loglevel Warning http://details:9080/details/0
1

其中，fortio-deploy-684b6b47f8-tzsg8是Fortio的Pod名称，效果如下：

流量镜像

目标：把流量全部路由到reviews服务的 v2 版本，再把流量全部镜像到 v3 版本。

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: reviews
spec:
  hosts:
  - reviews
  http:
  - route:
    - destination:
        host: reviews
        subset: v2
    mirror:
      host: reviews
      subset: v3
    mirrorPercentage:
      value: 100.0
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: reviews
spec:
  host: reviews
  subsets:
    - labels:
        version: v1
      name: v1
    - labels:
        version: v2
      name: v2
    - labels:
        version: v3
      name: v3
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执行如下命令查看reviews服务 v3 版本的 Envoy 访问日志：

kubectl logs -l app=reviews,version=v3 -c istio-proxy
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可以看到reviews服务 v3 版本被调用的日志：

{
     "authority": "reviews-shadow:9080",
     "bytes_received": 0,
     "bytes_sent": 375,
     "connection_termination_details": null,
     "downstream_local_address": "10.1.1.64:9080",
     "downstream_remote_address": "10.1.1.59:0",
     "duration": 1914,
     "method": "GET",
     "path": "/reviews/0",
     "protocol": "HTTP/1.1",
     "request_id": "b79cefe6-1277-9c39-b398-f94a704840cc",
     "requested_server_name": "outbound_.9080_.v3_.reviews.default.svc.cluster.local",
     "response_code": 200,
     "response_code_details": "via_upstream",
     "response_flags": "-",
     "route_name": "default",
     "start_time": "2022-06-27T07:34:19.129Z",
     "upstream_cluster": "inbound|9080||",
     "upstream_host": "10.1.1.64:9080",
     "upstream_local_address": "127.0.0.6:59837",
     "upstream_service_time": "1913",
     "upstream_transport_failure_reason": null,
     "user_agent": "curl/7.79.1",
     "x_forwarded_for": "10.1.1.59"
}
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Ingress的路由

目标：请求头app-id为details的所有流量都路由到details服务中。

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: bookinfo
spec:
  hosts:
    - '*'
  gateways:
    - bookinfo-gateway
  http:
    - match:
        - uri:
            exact: /productpage
        - uri:
            prefix: /static
        - uri:
            exact: /login
        - uri:
            exact: /logout
        - uri:
            prefix: /api/v1/products
      route:
        - destination:
            host: productpage
            port:
              number: 9080
    - match:
        - headers:
            app-id:
              exact: details
      route:
        - destination:
            host: details
            port:
              number: 9080
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使用curl命令验证一下：

curl -H "app-id: details" -v http://127.0.0.1/details/2
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返回结果如下：

* Trying 127.0.0.1:80...
* Connected to 127.0.0.1 (127.0.0.1) port 80 (#0)
> GET /details/2 HTTP/1.1
> Host: 127.0.0.1
> User-Agent: curl/7.79.1
> Accept: */*
> app-id: details
>
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< content-type: application/json
< server: istio-envoy
< date: Tue, 28 Jun 2022 07:14:40 GMT
< content-length: 178
< x-envoy-upstream-service-time: 4
<

{"id":2,"author":"William Shakespeare","year":1595,"type":"paperback","pages":200,"publisher":"PublisherA","language":"English","ISBN-10":"1234567890","ISBN-13":"123-1234567890"}

* Connection #0 to host 127.0.0.1 left intact
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返回结果可以看出，访问的是details服务。

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