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
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：
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 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。
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