Envoy流量分配策略优化

# HTTP Traffic Splitting Demo

### 环境说明
#### 六个Service:

- envoy：Front Proxy,地址为172.31.57.10
- 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:
              routes:
              - match:
                  prefix: "/"
                route:
                  weighted_clusters:
                    clusters:
                    - name: demoappv10
                      weight: 100
                    - name: demoappv11
                      weight: 0
                    total_weight: 100
                    runtime_key_prefix: routing.traffic_split.demoapp

启动

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

[root@k8s-master http-traffic-splitting]# 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: 172.31.57.10
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: 172.31.57.0/24
[root@k8s-master http-traffic-splitting]# 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:
routes:
- match:
prefix: "/"
route:
weighted_clusters:
clusters:
- name: demoappv10
weight: 100
- name: demoappv11
weight: 0
total_weight: 100
runtime_key_prefix: routing.traffic_split.demoapp
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-splitting]# 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

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

./send-request.sh 172.31.57.10

调整分发比例，将集群权重对调来模拟蓝绿部署，方法是在指定键（runtime_key）的值后附加以点号分隔的集群名称，并为其各自定义为相应的新权重值即可；

curl -XPOST 'http://172.31.57.10:9901/runtime_modify?routing.traffic_split.demoapp.demoappv10=0&routing.traffic_split.demoapp.demoappv11=100'