Load Reporting Service (LRS)

    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.

    The following documentation runs through the setup of Envoy described above.

    Ensure that you have a recent versions of and docker-compose installed.

    If you have not cloned the Envoy repo, clone it with:

    SSH

    HTTPS

    1. git clone https://github.com/envoyproxy/envoy.git

    Terminal 1

    1. $ pwd
    2. envoy/examples/load_reporting_service
    3. $ docker-compose ps
    4.                             Name                               Command               State                           Ports
    5. --------------------------------------------------------------------------------------------------------------------------------------
    7. 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
    8. load-reporting-service_lrs_server_1     go run main.go                   Up      0.0.0.0:18000->18000/tcp

    Terminal 2

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

    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. http_service_2  | 127.0.0.1 - - [12/Feb/2020 17:09:06] "GET /service HTTP/1.1" 200 -
    7. http_service_1  | 127.0.0.1 - - [12/Feb/2020 17:09:06] "GET /service HTTP/1.1" 200 -
    8. ............................
    9. 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 >
    10. 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 >
    11. http_service_2  | 127.0.0.1 - - [12/Feb/2020 17:09:07] "GET /service HTTP/1.1" 200 -
    12. http_service_1  | 127.0.0.1 - - [12/Feb/2020 17:09:07] "GET /service HTTP/1.1" 200 -
    13. ............................
    15. 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 >