HTTP请求重试条件

• 重试条件（同x-envoy-retry-on标头）

  • 5xx：上游主机返回5xx响应码，或者根本未予响应（断开/重置/读取超时）

  • gateway-error：网关错误，类似于5xx策略，但仅为502、503或504的应用进行重试

  • connection-failure：在TCP级别与上游服务建立连接失败时进行重试

  • retriable-4xx：上游服务器返回可重复的4xx响应码时进行重试

  • refused-stream：上游服器务使用REFUSED——STREAM错误码重置时进行重试

  • retriable-status-codes：上游服务器的响应码与重试策略或x-envoy-retriable-status-codes标头值中定义的响应码匹配时进行重试

  • reset：上游主机完全不响应时（disconnect/reset/read超时），Envoy将进行重试；

  • retriable-headers：如果上游服务器响应报文匹配重试策略或 x-envoy-retriable-header-names标头中包含的任何标头，则Envoy将尝试重试

  • envoy-ratelimited：标头中存在x-envoy-ratelimited时进行重试

• 重试条件2（同x-envoy-retry-grpc-on标头）

  • cancelled：gRPC应答标头中的状态码是“cancelled”时进行重试

  • deadline-exceeded：gRPC应答标头中的状态码是“deadline-exceeded”时进行重试

  • internal：gRPC应答标头中的状态码是“internal”时进行重试

  • resource-exhausted：gRPC应答标头中的状态码是“resource-exhausted”时进行重试

  • unavailable：gRPC应答标头中的状态码是“unavailable”时进行重试

• 默认情况下，Envoy不会进行任何类型的重试操作，除非明确定义

virtualservice-proxy.yaml

apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
  name: proxy
spec:
  hosts:
  - "app.wgs.com"                     # 对应于gateways/proxy-gateway
  - "proxy"
  - "proxy.default.svc"
  gateways:
  - istio-system/proxy-gateway       # 相关定义仅应用于Ingress Gateway上
  #- mesh
  http:
  - name: default
    route:
    - destination:
        host: proxy
    timeout: 1s
    retries:
      attempts: 5
      perTryTimeout: 1s
      retryOn: 5xx,connect-failure,refused-stream

virtualservice-demoapp.yaml

apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
  name: demoapp
spec:
  hosts:
  - demoapp
  http:
  - name: canary
    match:
    - uri:
        prefix: /canary
    rewrite:
      uri: /
    route:
    - destination:
        host: demoapp
        subset: v11
    fault:
      abort:
        percentage:
          value: 50
        httpStatus: 555
  - name: default
    route:
    - destination:
        host: demoapp
        subset: v10
    fault:
      delay:
        percentage:
          value: 50
        fixedDelay: 3s

更新demoapp svc

# kubectl apply -f virtualservice-demoapp.yaml -f virtualservice-proxy.yaml 
virtualservice.networking.istio.io/demoapp configured
virtualservice.networking.istio.io/proxy configured

访问demoapp

测试超时

upstream request timeout

~# while true;do curl app.wgs.com;sleep 0.5;done
upstream request timeoutProxying value: iKubernetes demoapp v1.0 !! ClientIP: 127.0.0.6, ServerName: demoappv10-78b6586d58-kdv4m, ServerIP: 172.20.154.195!
 - Took 5 milliseconds.
Proxying value: iKubernetes demoapp v1.0 !! ClientIP: 127.0.0.6, ServerName: demoappv10-78b6586d58-kdv4m, ServerIP: 172.20.154.195!
 - Took 5 milliseconds.
upstream request timeoutupstream request timeoutupstream request timeoutProxying value: iKubernetes demoapp v1.0 !! ClientIP: 127.0.0.6, ServerName: demoappv10-78b6586d58-kdv4m, ServerIP: 172.20.154.195!
 - Took 4 milliseconds.
upstream request timeoutProxying value: iKubernetes demoapp v1.0 !! ClientIP: 127.0.0.6, ServerName: demoappv10-78b6586d58-kdv4m, ServerIP: 172.20.154.195!
 - Took 4 milliseconds.

image

测试中断

~# while true;do curl app.wgs.com/canary;sleep 0.5;done
Proxying value: fault filter abort - Took 2 milliseconds.
Proxying value: iKubernetes demoapp v1.1 !! ClientIP: 127.0.0.6, ServerName: demoappv11-78bf898c74-hckjf, ServerIP: 172.20.89.189!
 - Took 4 milliseconds.
Proxying value: iKubernetes demoapp v1.1 !! ClientIP: 127.0.0.6, ServerName: demoappv11-78bf898c74-hckjf, ServerIP: 172.20.89.189!
 - Took 4 milliseconds.
Proxying value: iKubernetes demoapp v1.1 !! ClientIP: 127.0.0.6, ServerName: demoappv11-78bf898c74-hckjf, ServerIP: 172.20.89.189!
 - Took 5 milliseconds.
Proxying value: iKubernetes demoapp v1.1 !! ClientIP: 127.0.0.6, ServerName: demoappv11-78bf898c74-hckjf, ServerIP: 172.20.89.189!
 - Took 4 milliseconds.
Proxying value: iKubernetes demoapp v1.1 !! ClientIP: 127.0.0.6, ServerName: demoappv11-78bf898c74-hckjf, ServerIP: 172.20.89.189!
 - Took 5 milliseconds.
Proxying value: iKubernetes demoapp v1.1 !! ClientIP: 127.0.0.6, ServerName: demoappv11-78bf898c74-sn9qp, ServerIP: 172.20.154.253!
 - Took 3 milliseconds.
Proxying value: fault filter abort - Took 4 milliseconds.
Proxying value: fault filter abort - Took 2 milliseconds.
Proxying value: fault filter abort - Took 2 milliseconds.
Proxying value: iKubernetes demoapp v1.1 !! ClientIP: 127.0.0.6, ServerName: demoappv11-78bf898c74-hckjf, ServerIP: 172.20.89.189!
 - Took 4 milliseconds.
Proxying value: fault filter abort - Took 2 milliseconds.
Proxying value: iKubernetes demoapp v1.1 !! ClientIP: 127.0.0.6, ServerName: demoappv11-78bf898c74-hckjf, ServerIP: 172.20.89.189!
 - Took 4 milliseconds.
Proxying value: iKubernetes demoapp v1.1 !! ClientIP: 127.0.0.6, ServerName: demoappv11-78bf898c74-sn9qp, ServerIP: 172.20.154.253!
 - Took 4 milliseconds.

image

参考文档

https://istio.io/latest/zh/docs/reference/config/networking/virtual-service/#HTTPRetry