Load reporting service (LRS)

Requirements

Sandbox environment

Setup your sandbox environment with Docker and Docker Compose, and clone the Envoy repository with Git.

This simple example demonstrates Envoy’s Load reporting service (LRS) capability and how to use it.

Lets say Cluster A (downstream) talks to Cluster B (Upstream) and Cluster C (Upstream). When enabling Load Report for Cluster A, LRS server should be sending LoadStatsResponse to Cluster A with LoadStatsResponse.Clusters to be B and C. LRS server will then receive LoadStatsRequests (with total requests, successful requests etc) from Cluster A to Cluster B and from Cluster A to Cluster C.

In this example, all incoming requests are routed via Envoy to a simple goLang web server aka http_server. We scale up two containers and randomly send requests to each. Envoy is configured to initiate the connection with LRS Server. LRS Server enables the stats by sending LoadStatsResponse. Sending requests to http_server will be counted towards successful requests and will be visible in LRS Server logs.

Step 1: Build the sandbox

Change to the examples/load-reporting-service directory.

Terminal 1

  1. $ pwd
  2. envoy/examples/load-reporting-service
  3. $ docker-compose pull
  4. $ docker-compose up --scale http_service=2

Terminal 2

  1. $ pwd
  2. envoy/examples/load_reporting_service
  3. $ docker-compose ps
  5.               Name                               Command               State            Ports
  6. ------------------------------------------------------------------------------------------------------------
  7. load-reporting-service_http_service_1   /bin/sh -c /usr/local/bin/ ... Up      10000/tcp, 0.0.0.0:81->80/tcp
  8. load-reporting-service_http_service_2   /bin/sh -c /usr/local/bin/ ... Up      10000/tcp, 0.0.0.0:80->80/tcp
  9. load-reporting-service_lrs_server_1     go run main.go                 Up      0.0.0.0:18000->18000/tcp

Step 2: Start sending stream of HTTP requests

Terminal 2

  1. $ pwd
  2. envoy/examples/load_reporting_service
  3. $ bash send_requests.sh

The script above (send_requests.sh) sends requests randomly to each Envoy, which in turn forwards the requests to the backend service.

Step 3: See Envoy Stats

You should see

Terminal 1

  1. ............................
  2. lrs_server_1    | 2020/02/12 17:08:20 LRS Server is up and running on :18000
  3. lrs_server_1    | 2020/02/12 17:08:23 Adding new cluster to cache `http_service` with node `0022a319e1e2`
  4. lrs_server_1    | 2020/02/12 17:08:24 Adding new node `2417806c9d9a` to existing cluster `http_service`
  5. lrs_server_1    | 2020/02/12 17:08:25 Creating LRS response for cluster http_service, node 2417806c9d9a with frequency 2 secs
  6. lrs_server_1    | 2020/02/12 17:08:25 Creating LRS response for cluster http_service, node 0022a319e1e2 with frequency 2 secs
  7. http_service_2  | 127.0.0.1 - - [12/Feb/2020 17:09:06] "GET /service HTTP/1.1" 200 -
  8. http_service_1  | 127.0.0.1 - - [12/Feb/2020 17:09:06] "GET /service HTTP/1.1" 200 -
  9. ............................
  10. 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 >
  11. 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 >
  12. http_service_2  | 127.0.0.1 - - [12/Feb/2020 17:09:07] "GET /service HTTP/1.1" 200 -
  13. http_service_1  | 127.0.0.1 - - [12/Feb/2020 17:09:07] "GET /service HTTP/1.1" 200 -
  14. ............................
  15. 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 >
  16. 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 >

See also

Load reporting service

Overview of Envoy’s Load reporting service.

Load reporting service API(V3)

The Load reporting service API.