Envoy负载均衡

还用之前下载的代码

cd servicemesh_in_practise/Cluster-Manager/ring-hash

cat docker-compose.yaml 
# Author: MageEdu <mage@magedu.com>
# Version: v1.0.1
# Site: www.magedu.com
#
version: '3.3'

services:
  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: 172.31.25.2
        aliases:
        - front-proxy
    depends_on:
    - webserver01-sidecar
    - webserver02-sidecar
    - webserver03-sidecar

  webserver01-sidecar:
    image: envoyproxy/envoy-alpine:v1.21-latest
    environment:
      - ENVOY_UID=0
      - ENVOY_GID=0
    volumes:
    - ./envoy-sidecar-proxy.yaml:/etc/envoy/envoy.yaml
    hostname: red
    networks:
      envoymesh:
        ipv4_address: 172.31.25.11
        aliases:
        - myservice
        - red

  webserver01:
    image: ikubernetes/demoapp:v1.0
    environment:
      - ENVOY_UID=0
      - ENVOY_GID=0
    environment:
      - PORT=8080
      - HOST=127.0.0.1
    network_mode: "service:webserver01-sidecar"
    depends_on:
    - webserver01-sidecar

  webserver02-sidecar:
    image: envoyproxy/envoy-alpine:v1.21-latest
    environment:
      - ENVOY_UID=0
      - ENVOY_GID=0
    volumes:
    - ./envoy-sidecar-proxy.yaml:/etc/envoy/envoy.yaml
    hostname: blue
    networks:
      envoymesh:
        ipv4_address: 172.31.25.12
        aliases:
        - myservice
        - blue

  webserver02:
    image: ikubernetes/demoapp:v1.0
    environment:
      - ENVOY_UID=0
      - ENVOY_GID=0
    environment:
      - PORT=8080
      - HOST=127.0.0.1
    network_mode: "service:webserver02-sidecar"
    depends_on:
    - webserver02-sidecar

  webserver03-sidecar:
    image: envoyproxy/envoy-alpine:v1.21-latest
    environment:
      - ENVOY_UID=0
      - ENVOY_GID=0
    volumes:
    - ./envoy-sidecar-proxy.yaml:/etc/envoy/envoy.yaml
    hostname: green
    networks:
      envoymesh:
        ipv4_address: 172.31.25.13
        aliases:
        - myservice
        - green

  webserver03:
    image: ikubernetes/demoapp:v1.0
    environment:
      - ENVOY_UID=0
      - ENVOY_GID=0
    environment:
      - PORT=8080
      - HOST=127.0.0.1
    network_mode: "service:webserver03-sidecar"
    depends_on:
    - webserver03-sidecar

networks:
  envoymesh:
    driver: bridge
    ipam:
      config:
        - subnet: 172.31.25.0/24
cat envoy-sidecar-proxy.yaml 
# Author: MageEdu <mage@magedu.com>
# Version: v1.0.1
# Site: www.magedu.com
#
admin:
  profile_path: /tmp/envoy.prof
  access_log_path: /tmp/admin_access.log
  address:
    socket_address:
       address: 0.0.0.0
       port_value: 9901

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: local_service 
              domains: ["*"]
              routes:
              - match: { prefix: "/" }
                route: { cluster: local_cluster }
          http_filters:
          - name: envoy.filters.http.router

  clusters:
  - name: local_cluster
    connect_timeout: 0.25s
    type: STATIC
    lb_policy: ROUND_ROBIN
    load_assignment:
      cluster_name: local_cluster
      endpoints:
      - lb_endpoints:
        - endpoint:
            address:
              socket_address: { address: 127.0.0.1, port_value: 8080 }
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 }

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: webservice
              domains: ["*"]
              routes:
              - match: { prefix: "/" }
                route:
                  cluster: web_cluster_01
                  hash_policy:
                  # - connection_properties:
                  #     source_ip: true
                  - header:
                      header_name: User-Agent
          http_filters:
          - name: envoy.filters.http.router

  clusters:
  - name: web_cluster_01
    connect_timeout: 0.5s
    type: STRICT_DNS
    lb_policy: RING_HASH
    ring_hash_lb_config:
      maximum_ring_size: 1048576
      minimum_ring_size: 512
    load_assignment:
      cluster_name: web_cluster_01
      endpoints:
      - lb_endpoints:
        - endpoint:
            address:
              socket_address:
                address: myservice
                port_value: 80
    health_checks:
    - timeout: 5s
      interval: 10s
      unhealthy_threshold: 2
      healthy_threshold: 2
      http_health_check:
        path: /livez
        expected_statuses:
          start: 200
          end: 399

启动

docker-compose up

我们在路由hash策略中，hash计算的是用户的浏览器类型，因而，使用如下命令持续发起请求可以看出，用户请求将始终被定向到同一个后端端点；因为其浏览器类型一直未变。

while true; do curl 172.31.25.2; sleep .3; done

我们可以模拟使用另一个浏览器再次发请求；其请求可能会被调度至其它节点，也可能仍然调度至前一次的相同节点之上；这取决于hash算法的计算结果；

while true; do curl -H "User-Agent: Hello" 172.31.25.2; sleep .3; done

也可以使用如下命令，将一个后端端点的健康检查结果置为失败，动态改变端点，并再次判定其调度结果，验证此前调度至该节点的请求是否被重新分配到了其它节点；

curl -X POST -d 'livez=FAIL' http://172.31.25.12/livez

可以看到当livez设置为FAIL后ServerName从blue变成了red