Envoy流量分流

# HTTP Traffic Shifting Demo

### 环境说明
#### 六个Service:

- envoy：Front Proxy,地址为172.31.55.10
- 5个后端服务
  - demoapp-v1.0-1、demoapp-v1.0-2和demoapp-v1.0-3：对应于Envoy中的demoappv10集群
  - demoapp-v1.1-1和demoapp-v1.1-2：对应于Envoy中的demoappv11集群

#### 使用的路由配置

```
            virtual_hosts:
            - name: demoapp
              domains: ["*"]
              routes:
              - match:
                  prefix: "/"
                  runtime_fraction:
                    default_value:
                      numerator: 100
                      denominator: HUNDRED
                    runtime_key: routing.traffic_shift.demoapp
                route:
                  cluster: demoappv10
              - match:
                  prefix: "/"
                route:
                  cluster: demoappv11

启动

cd servicemesh_in_practise/HTTP-Connection-Manager/http-traffic-shifting
docker-compose up

[root@k8s-master http-traffic-shifting]# cat docker-compose.yaml 
version: '3'

services:
  front-envoy:
    image: envoyproxy/envoy-alpine:v1.21-latest
    environment:
      - ENVOY_UID=0
      - ENVOY_GID=0
    volumes:
      - ./front-envoy.yaml:/etc/envoy/envoy.yaml
    networks:
      envoymesh:
        ipv4_address: 172.31.55.10
    expose:
      # Expose ports 80 (for general traffic) and 9901 (for the admin server)
      - "80"
      - "9901"

  demoapp-v1.0-1:
    image: ikubernetes/demoapp:v1.0
    hostname: demoapp-v1.0-1
    networks:
      envoymesh:
        aliases:
          - demoappv10
    expose:
      - "80"      
      
  demoapp-v1.0-2:
    image: ikubernetes/demoapp:v1.0
    hostname: demoapp-v1.0-2
    networks:
      envoymesh:
        aliases:
          - demoappv10
    expose:
      - "80"  
      
  demoapp-v1.0-3:
    image: ikubernetes/demoapp:v1.0
    hostname: demoapp-v1.0-3
    networks:
      envoymesh:
        aliases:
          - demoappv10
    expose:
      - "80" 
      
  demoapp-v1.1-1:
    image: ikubernetes/demoapp:v1.1
    hostname: demoapp-v1.1-1
    networks:
      envoymesh:
        aliases:
          - demoappv11
    expose:
      - "80"      
      
  demoapp-v1.1-2:
    image: ikubernetes/demoapp:v1.1
    hostname: demoapp-v1.1-2
    networks:
      envoymesh:
        aliases:
          - demoappv11
    expose:
      - "80"  

networks:
  envoymesh:
    driver: bridge
    ipam:
      config:
        - subnet: 172.31.55.0/24
[root@k8s-master http-traffic-shifting]# cat front-envoy.yaml 
admin:
  profile_path: /tmp/envoy.prof
  access_log_path: /tmp/admin_access.log
  address:
    socket_address:
       address: 0.0.0.0
       port_value: 9901

layered_runtime:
  layers:
  - name: admin
    admin_layer: {}
       
static_resources:
  listeners:
  - name: listener_0
    address:
      socket_address: { address: 0.0.0.0, port_value: 80 }
    filter_chains:
    - filters:
      - name: envoy.filters.network.http_connection_manager
        typed_config:
          "@type": type.googleapis.com/envoy.extensions.filters.network.http_connection_manager.v3.HttpConnectionManager
          stat_prefix: ingress_http
          codec_type: AUTO
          route_config:
            name: local_route
            virtual_hosts:
            - name: demoapp
              domains: ["*"]
              routes:
              - match:
                  prefix: "/"
                  runtime_fraction:
                    default_value:
                      numerator: 100
                      denominator: HUNDRED
                    runtime_key: routing.traffic_shift.demoapp
                route:
                  cluster: demoappv10
              - match:
                  prefix: "/"
                route:
                  cluster: demoappv11
          http_filters:
          - name: envoy.filters.http.router

  clusters:
  - name: demoappv10
    connect_timeout: 0.25s
    type: STRICT_DNS
    lb_policy: ROUND_ROBIN
    load_assignment:
      cluster_name: demoappv10
      endpoints:
      - lb_endpoints:
        - endpoint:
            address:
              socket_address:
                address: demoappv10
                port_value: 80

  - name: demoappv11
    connect_timeout: 0.25s
    type: STRICT_DNS
    lb_policy: ROUND_ROBIN
    load_assignment:
      cluster_name: demoappv11
      endpoints:
      - lb_endpoints:
        - endpoint:
            address:
              socket_address:
                address: demoappv11
                port_value: 80
                     
[root@k8s-master http-traffic-shifting]# cat send-request.sh 
#!/bin/bash
declare -i ver10=0
declare -i ver11=0

interval="0.2"

while true; do
	if curl -s http://$1/hostname | grep "demoapp-v1.0" &> /dev/null; then
		# $1 is the host address of the front-envoy.
		ver10=$[$ver10+1]
	else
		ver11=$[$ver11+1]
	fi
	echo "demoapp-v1.0:demoapp-v1.1 = $ver10:$ver11"
	sleep $interval
done

 

运行测试脚本send-request.sh

脚本需要front-envoy的地址为参数，并每隔两秒钟向其发起一次HTTP请求

此时所有流量，都将由集群demoappv10所承载，因为默认配置中，100%的流量比例将保留给该集群

将保留给demoappv10集群的流量比例调整为90%，方法是将指定键的值定义为相应的分子数即可

curl -XPOST http://172.31.55.10:9901/runtime_modify?routing.traffic_shift.demoapp=90

重新运行测试脚本，测试的时间越长，样本数越大，越能接近于实际比例，事实上，我们完全可以阶段性地多次进行流量比例的微调。