10个 Istio 流量管理最常用的例子，你知道几个？

旧城等待， 2023-09-28 13:43 65阅读 0赞

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：

![薇信搜索：万猫学社，关注后回复「ebook」得12本必读技术书籍。][ebook_12]

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

> **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

> **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

#### 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

#### 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

#### 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

#### 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

在Jaeger可以看到具体的调用链如下：

![aa4cfcf1264016b372fdd27a813c8440.png][]

#### 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

#### 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"]

#### 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

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 2`0）：

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

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

![1a268f18facb5c7340f16aa451417cda.png][]

#### 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

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

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"
    }

#### 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

使用curl命令验证一下：

curl -H "app-id: details" -v http://127.0.0.1/details/2

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

返回结果可以看出，访问的是`details`服务。

> 最后，感谢你这么帅，还给我**点赞**。

[ebook_12]: https://img-blog.csdnimg.cn/img_convert/16ef83599fd3611e63f0c389cf5758d8.png
[aa4cfcf1264016b372fdd27a813c8440.png]: https://img-blog.csdnimg.cn/img_convert/aa4cfcf1264016b372fdd27a813c8440.png
[1a268f18facb5c7340f16aa451417cda.png]: https://img-blog.csdnimg.cn/img_convert/1a268f18facb5c7340f16aa451417cda.png