负载报告服务 (LRS)¶
这个简单的例子展示了负载报告服务 (LRS) 的特性以及如何使用它。
假设下游集群 A 和上游集群 B 以及上游集群 C 进行交互。当我们打开了集群 A 的负载报告功能，LRS 服务器即会向集群 A 发送 LoadStatsResponse 并且向集群 B 和 集群 C 发送 LoadStatsResponse.Clusters。 接着，LRS 服务器随后就将收到来自集群 A、集群 B 和集群 C 的 LoadStatsRequests （包括所有请求，成功请求等）。
在这个例子中，所有的入向请求都被 Envoy 路由到一个简单的 golang web server，我们称之为 http_server。 我们为这个 http_server 初始化了两个容器实例，这两个实例会随机地向对方发送请求。并配置 Envoy 建立到 LRS 服务器的连接。 LRS 服务器通过发送 LoadStatsResponse 来使能状态统计。所有发向 http_server 的成功请求会被计数并且显示在 LRS 服务器的log中。
运行沙盒¶
以下文档说明了上述对于 Envoy 容器编译环境进行设置的过程。
步骤 2：克隆 Envoy 仓库¶
如果你还没有克隆 Envoy 仓库，用如下方式进行克隆：
git clone [email protected]:envoyproxy/envoy
git clone https://github.com/envoyproxy/envoy.git
步骤 3: 构建沙盒¶
终端 1
$ pwd
envoy/examples/load_reporting_service
$ docker-compose pull
$ docker-compose up --scale http_service=2
终端 2
$ pwd
envoy/examples/load_reporting_service
$ docker-compose ps
Name Command State Ports
--------------------------------------------------------------------------------------------------------------------------------------
load-reporting-service_http_service_1 /bin/sh -c /usr/local/bin/ ... Up 10000/tcp, 0.0.0.0:80->80/tcp, 0.0.0.0:8081->8081/tcp
load-reporting-service_http_service_2 /bin/sh -c /usr/local/bin/ ... Up 10000/tcp, 0.0.0.0:81->80/tcp, 0.0.0.0:8082->8081/tcp
load-reporting-service_lrs_server_1 go run main.go Up 0.0.0.0:18000->18000/tcp
步骤 4: 开始发送 HTTP 请求流¶
终端 2
$ pwd
envoy/examples/load_reporting_service
$ bash send_requests.sh
上面的脚本（send_requests.sh）会随机地向每个 Envoy 发送请求，随后这些请求会被转发到后端服务。
步骤 5: 查看 Envoy 统计数据¶
你会看到如下结果
终端 1
............................
lrs_server_1 | 2020/02/12 17:08:20 LRS Server is up and running on :18000
lrs_server_1 | 2020/02/12 17:08:23 Adding new cluster to cache `http_service` with node `0022a319e1e2`
lrs_server_1 | 2020/02/12 17:08:24 Adding new node `2417806c9d9a` to existing cluster `http_service`
lrs_server_1 | 2020/02/12 17:08:25 Creating LRS response for cluster http_service, node 2417806c9d9a with frequency 2 secs
lrs_server_1 | 2020/02/12 17:08:25 Creating LRS response for cluster http_service, node 0022a319e1e2 with frequency 2 secs
http_service_2 | 127.0.0.1 - - [12/Feb/2020 17:09:06] "GET /service HTTP/1.1" 200 -
http_service_1 | 127.0.0.1 - - [12/Feb/2020 17:09:06] "GET /service HTTP/1.1" 200 -
............................
lrs_server_1 | 2020/02/12 17:09:07 Got stats from cluster `http_service` node `0022a319e1e2` - cluster_name:"local_service" upstream_locality_stats:<locality:<> total_successful_requests:21 total_issued_requests:21 > load_report_interval:<seconds:1 nanos:998411000 >
lrs_server_1 | 2020/02/12 17:09:07 Got stats from cluster `http_service` node `2417806c9d9a` - cluster_name:"local_service" upstream_locality_stats:<locality:<> total_successful_requests:17 total_issued_requests:17 > load_report_interval:<seconds:1 nanos:994529000 >
http_service_2 | 127.0.0.1 - - [12/Feb/2020 17:09:07] "GET /service HTTP/1.1" 200 -
http_service_1 | 127.0.0.1 - - [12/Feb/2020 17:09:07] "GET /service HTTP/1.1" 200 -
............................
lrs_server_1 | 2020/02/12 17:09:09 Got stats from cluster `http_service` node `0022a319e1e2` - cluster_name:"local_service" upstream_locality_stats:<locality:<> total_successful_requests:3 total_issued_requests:3 > load_report_interval:<seconds:2 nanos:2458000 >
lrs_server_1 | 2020/02/12 17:09:09 Got stats from cluster `http_service` node `2417806c9d9a` - cluster_name:"local_service" upstream_locality_stats:<locality:<> total_successful_requests:9 total_issued_requests:9 > load_report_interval:<seconds:2 nanos:6487000 >