如何配置请求重试_服务网格(ASM)-阿里云帮助中心

ASM支持定义在HTTP请求失败时使用的重试策略，可以指定每次重试允许的超时时间、重试次数、重试条件等。本文介绍如何配置请求重试。

前提条件

已完成准备工作，并部署httpbin服务和sleep服务。具体操作，请参见准备工作。

操作步骤

验证服务配置是否生效。

在ACK集群对应的KubeConfig环境下，执行以下命令，进入sleep环境开启bash。
```
kubectl exec -it deploy/sleep -- sh
```

执行以下命令，向httpbin服务发送请求。

curl -I httpbin:8000/status/500

预期输出：

HTTP/1.1 500 Internal Server Error
server: envoy
date: Fri, 11 Aug 2023 10:03:06 GMT
content-type: text/html; charset=utf-8
access-control-allow-origin: *
access-control-allow-credentials: true
content-length: 0
x-envoy-upstream-service-time: 2

使用以下内容，构建测试场景，配置httpbin应用的流量规则，重试策略配置为在请求响应5xx时重试五次。具体操作，请参见管理虚拟服务。

apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
  name: httpbin-vs
  namespace: default
spec:
  hosts:
    - httpbin
  http:
    - retries:
        attempts: 5
        retryOn: 5xx
      route:
        - destination:
            host: httpbin

验证配置是否生效。

在ACK集群对应的KubeConfig环境下，执行以下命令，进入sleep环境开启bash。
```
kubectl exec -it deploy/sleep -- sh
```

执行以下命令，向httpbin服务发送请求，设置响应状态500。

curl -I httpbin:8000/status/500

预期输出：

HTTP/1.1 500 Internal Server Error
server: envoy
date: Fri, 11 Aug 2023 10:03:35 GMT
content-type: text/html; charset=utf-8
access-control-allow-origin: *
access-control-allow-credentials: true
content-length: 0
x-envoy-upstream-service-time: 382

修改sleep日志级别，以便查看Retry过程日志。
1. 执行以下命令，进入sleep Pod内部。
```
kubectl exec -it {sleep Pod名称} -- sh 
```
2. 执行以下命令，修改日志级别。
```
curl -XPOST http://localhost:15000/logging\?level\=debug
```

执行以下命令，查看sleep日志。

kubectl logs {sleep Pod名称} -c istio-proxy |grep -i retry

预期输出：

2023-08-14T02:11:01.896684Z	debug	envoy router external/envoy/source/common/router/router.cc:1862	[C159776][S1686768772862290****] performing retry	thread=36
2023-08-14T02:11:01.932148Z	debug	envoy router external/envoy/source/common/router/router.cc:1862	[C159776][S1686768772862290****] performing retry	thread=36
2023-08-14T02:11:02.020689Z	debug	envoy router external/envoy/source/common/router/router.cc:1862	[C159776][S1686768772862290****] performing retry	thread=36
2023-08-14T02:11:02.170440Z	debug	envoy router external/envoy/source/common/router/router.cc:1862	[C159776][S1686768772862290****] performing retry	thread=36
2023-08-14T02:11:02.275478Z	debug	envoy router external/envoy/source/common/router/router.cc:1862	[C159776][S1686768772862290****] performing retry	thread=36