Envoy-负载均衡器子集(Subset) 【九】

 

 

实验示例：

[root@k8s-master01 lb-subsets]# ll
total 20
-rw-r--r-- 1 root root 1849 Feb 21 09:00 docker-compose.yaml
-rw-r--r-- 1 root root 5241 Aug  5  2022 front-envoy.yaml
-rw-r--r-- 1 root root 1333 Aug  5  2022 README.md
-rwxr-xr-x 1 root root  293 Aug  5  2022 test.sh

1.README.md

[root@k8s-master01 lb-subsets]# cat README.md
# LB Subset Cluster Demo

### 环境说明
五个Service:
- envoy：Front Proxy,地址为172.31.33.2
- [e1, e7]：7个后端服务

### 运行和测试
1. 创建
```
docker-compose up
```

2. 测试
```
# test.sh脚本接受front-envoy的地址，并持续向该地址发起请求，而后显示流量分配的结果；根据路由规则，未指定x-hardware-test和x-custom-version且给予了相应值的请求，均会调度给默认子集，且在两个组之间进行流量分发；
./test.sh 172.31.33.2

# 我们可以指定特殊的首部发出特定的请求，例如附带有”x-hardware-test: memory”的请求，将会被分发至特定的子集；该子集要求标签type的值为bigmem，而标签stage的值为prod；该子集共有e5和e6两个端点
curl -H "x-hardware-test: memory" 172.31.33.2/hostname

# 或者，我们也可以指定特殊的首部发出特定的请求，例如附带有”x-custom-version: pre-release”的请求，将会被分发至特定的子集；该子集要求标签version的值为1.2-pre，而标签stage的值为dev；该子集有e7一个端点;
curl -H "x-custom-version: pre-release" 172.31.33.2/hostname
```

3. 停止后清理
```
docker-compose down
```

2.docker-compose.yaml

#定义了7个端点 e1~e7

# docker-compose.yaml
[root@k8s-master01 lb-subsets]# 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: 172.31.33.2
    expose:
      # Expose ports 80 (for general traffic) and 9901 (for the admin server)
      - "80"
      - "9901"

  e1:
    image: ikubernetes/demoapp:v1.0
    hostname: e1
    networks:
      envoymesh:
        ipv4_address: 172.31.33.11
        aliases:
          - e1
    expose:
      - "80"

  e2:
    image: ikubernetes/demoapp:v1.0
    hostname: e2
    networks:
      envoymesh:
        ipv4_address: 172.31.33.12
        aliases:
          - e2
    expose:
      - "80"

  e3:
    image: ikubernetes/demoapp:v1.0
    hostname: e3
    networks:
      envoymesh:
        ipv4_address: 172.31.33.13
        aliases:
          - e3
    expose:
      - "80"

  e4:
    image: ikubernetes/demoapp:v1.0
    hostname: e4
    networks:
      envoymesh:
        ipv4_address: 172.31.33.14
        aliases:
          - e4
    expose:
      - "80"

  e5:
    image: ikubernetes/demoapp:v1.0
    hostname: e5
    networks:
      envoymesh:
        ipv4_address: 172.31.33.15
        aliases:
          - e5
    expose:
      - "80"

  e6:
    image: ikubernetes/demoapp:v1.0
    hostname: e6
    networks:
      envoymesh:
        ipv4_address: 172.31.33.16
        aliases:
          - e6
    expose:
      - "80"

  e7:
    image: ikubernetes/demoapp:v1.0
    hostname: e7
    networks:
      envoymesh:
        ipv4_address: 172.31.33.17
        aliases:
          - e7
    expose:
      - "80"

networks:
  envoymesh:
    driver: bridge
    ipam:
      config:
        - subnet: 172.31.33.0/24

3.front-envoy.yaml

#          route_config:下定义了转发路由规则 根据匹配条目转发到指定端点上
#  clusters:下定义各个端点的标签 用于匹配          
#    lb_subset_config: 定义了负载均衡子集 此示例有11个子集

[root@k8s-master01 lb-subsets]# cat front-envoy.yaml
admin:
  access_log_path: "/dev/null"
  address:
    socket_address: { address: 0.0.0.0, port_value: 9901 }

static_resources:
  listeners:
  - address:
      socket_address: { address: 0.0.0.0, port_value: 80 }
    name: listener_http
    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
          codec_type: auto
          stat_prefix: ingress_http
          route_config:
            name: local_route
            virtual_hosts:
            - name: backend
              domains:
              - "*"
              routes:
              - match:
                  prefix: "/"
                  headers:
                  - name: x-custom-version
                    exact_match: pre-release
                route:
                  cluster: webcluster1
                  metadata_match:
                    filter_metadata:
                      envoy.lb:
                        version: "1.2-pre"
                        stage: "dev"
              - match:
                  prefix: "/"
                  headers:
                  - name: x-hardware-test
                    exact_match: memory
                route:
                  cluster: webcluster1
                  metadata_match:
                    filter_metadata:
                      envoy.lb:
                        type: "bigmem"
                        stage: "prod"
              - match:
                  prefix: "/"
                route:
                  weighted_clusters:
                    clusters:
                    - name: webcluster1
                      weight: 90
                      metadata_match:
                        filter_metadata:
                          envoy.lb:
                            version: "1.0"
                    - name: webcluster1
                      weight: 10
                      metadata_match:
                        filter_metadata:
                          envoy.lb:
                            version: "1.1"
                  metadata_match:
                    filter_metadata:
                      envoy.lb:
                        stage: "prod"
          http_filters:
          - name: envoy.filters.http.router

  clusters:
  - name: webcluster1
    connect_timeout: 0.5s
    type: STRICT_DNS
    lb_policy: ROUND_ROBIN
    load_assignment:
      cluster_name: webcluster1
      endpoints:
      - lb_endpoints:
        - endpoint:
            address:
              socket_address:
                address: e1
                port_value: 80
          metadata:
            filter_metadata:
              envoy.lb:
                stage: "prod"
                version: "1.0"
                type: "std"
                xlarge: true
        - endpoint:
            address:
              socket_address:
                address: e2
                port_value: 80
          metadata:
            filter_metadata:
              envoy.lb:
                stage: "prod"
                version: "1.0"
                type: "std"
        - endpoint:
            address:
              socket_address:
                address: e3
                port_value: 80
          metadata:
            filter_metadata:
              envoy.lb:
                stage: "prod"
                version: "1.1"
                type: "std"
        - endpoint:
            address:
              socket_address:
                address: e4
                port_value: 80
          metadata:
            filter_metadata:
              envoy.lb:
                stage: "prod"
                version: "1.1"
                type: "std"
        - endpoint:
            address:
              socket_address:
                address: e5
                port_value: 80
          metadata:
            filter_metadata:
              envoy.lb:
                stage: "prod"
                version: "1.0"
                type: "bigmem"
        - endpoint:
            address:
              socket_address:
                address: e6
                port_value: 80
          metadata:
            filter_metadata:
              envoy.lb:
                stage: "prod"
                version: "1.1"
                type: "bigmem"
        - endpoint:
            address:
              socket_address:
                address: e7
                port_value: 80
          metadata:
            filter_metadata:
              envoy.lb:
                stage: "dev"
                version: "1.2-pre"
                type: "std"
    lb_subset_config:
      fallback_policy: DEFAULT_SUBSET
      default_subset:
        stage: "prod"
        version: "1.0"
        type: "std"
      subset_selectors:
      - keys: ["stage", "type"]
      - keys: ["stage", "version"]
      - keys: ["version"]
      - keys: ["xlarge", "version"]
    health_checks:
    - timeout: 5s
      interval: 10s
      unhealthy_threshold: 2
      healthy_threshold: 1
      http_health_check:
        path: /livez
        expected_statuses:
          start: 200
          end: 399

4.test.sh

#test.sh
[root@k8s-master01 lb-subsets]# cat test.sh
#!/bin/bash
declare -i v10=0
declare -i v11=0

for ((counts=0; counts<200; counts++)); do
        if curl -s http://$1/hostname | grep -E "e[125]" &> /dev/null; then
                # $1 is the host address of the front-envoy.
                v10=$[$v10+1]
        else
                v11=$[$v11+1]
        fi
done

echo "Requests: v1.0:v1.1 = $v10:$v11"

5.测试

# test.sh脚本接受front-envoy的地址，并持续向该地址发起请求，而后显示流量分配的结果；根据路由规则，未指定x-hardware-test和x-custom-version且给予了相应值的请求，均会调度给默认子集，且在两个组之间进行流量分发；
[root@k8s-master01 lb-subsets]# ./test.sh 172.31.33.2
Requests: v1.0:v1.1 = 179:21

# 我们可以指定特殊的首部发出特定的请求，例如附带有”x-hardware-test: memory”的请求，将会被分发至特定的子集；该子集要求标签type的值为bigmem，而标签stage的值为prod；该子集共有e5和e6两个端点
[root@k8s-master01 lb-subsets]# curl -H "x-hardware-test: memory" 172.31.33.2/hostname
ServerName: e5
You have new mail in /var/spool/mail/root
[root@k8s-master01 lb-subsets]# curl -H "x-hardware-test: memory" 172.31.33.2/hostname
ServerName: e6
[root@k8s-master01 lb-subsets]# curl -H "x-hardware-test: memory" 172.31.33.2/hostname
ServerName: e5
[root@k8s-master01 lb-subsets]# curl -H "x-hardware-test: memory" 172.31.33.2/hostname
ServerName: e6
[root@k8s-master01 lb-subsets]# curl -H "x-hardware-test: memory" 172.31.33.2/hostname
ServerName: e6
[root@k8s-master01 lb-subsets]# curl -H "x-hardware-test: memory" 172.31.33.2/hostname
ServerName: e5

# 或者，我们也可以指定特殊的首部发出特定的请求，例如附带有”x-custom-version: pre-release”的请求，将会被分发至特定的子集；该子集要求标签version的值为1.2-pre，而标签stage的值为dev；该子集有e7一个端点;
[root@k8s-master01 lb-subsets]# curl -H "x-custom-version: pre-release" 172.31.33.2/hostname
ServerName: e7
[root@k8s-master01 lb-subsets]# curl -H "x-custom-version: pre-release" 172.31.33.2/hostname
ServerName: e7
[root@k8s-master01 lb-subsets]# curl -H "x-custom-version: pre-release" 172.31.33.2/hostname
ServerName: e7
[root@k8s-master01 lb-subsets]# curl -H "x-custom-version: pre-release" 172.31.33.2/hostname
ServerName: e7