ugodiggi / grpc-envoy-loadbalancer

Example gRPC load-balancer using Envoy

Envoy + gRPC - Basic Load-Balancing

This example used an edge-proxy (frontend/front-envoy) to accept incoming GRPC calls and routes them to a set of backend services which fullfil the requests.

The client creates a single gRPC stub to the edge-proxy and calls stub.SayHelloRequest 10 times. When both helloworld services are up and running each succesive call gets properly load-balanced between the backend services. This is an example of L7 load- balancing of HTTP2 requests.

Quickstart

In one window,

docker-compose up

In another window, run the client:

cd client
docker-compose run --rm client

You can target each of the individual instances on ports 9001 and 9002 respectively.

Example output:

ubuntu@dgx:~/gtc_18/envoy/examples/grpc-proxy/client$ docker-compose run --rm client
Greeter client received: Hello, you from host=ca2310cf3b73!
Greeter client received: Hello, you from host=114c199e6bdb!
Greeter client received: Hello, you from host=ca2310cf3b73!
Greeter client received: Hello, you from host=114c199e6bdb!
Greeter client received: Hello, you from host=ca2310cf3b73!
Greeter client received: Hello, you from host=114c199e6bdb!
Greeter client received: Hello, you from host=ca2310cf3b73!
Greeter client received: Hello, you from host=114c199e6bdb!
Greeter client received: Hello, you from host=ca2310cf3b73!
Greeter client received: Hello, you from host=114c199e6bdb!
ubuntu@dgx:~/gtc_18/envoy/examples/grpc-proxy/client$ ADDRESS=localhost:9001 docker-compose run --rm client
Greeter client received: Hello, you from host=ca2310cf3b73!
Greeter client received: Hello, you from host=ca2310cf3b73!
Greeter client received: Hello, you from host=ca2310cf3b73!
Greeter client received: Hello, you from host=ca2310cf3b73!
Greeter client received: Hello, you from host=ca2310cf3b73!
Greeter client received: Hello, you from host=ca2310cf3b73!
Greeter client received: Hello, you from host=ca2310cf3b73!
Greeter client received: Hello, you from host=ca2310cf3b73!
Greeter client received: Hello, you from host=ca2310cf3b73!
Greeter client received: Hello, you from host=ca2310cf3b73!
ubuntu@dgx:~/gtc_18/envoy/examples/grpc-proxy/client$ ADDRESS=localhost:9002 docker-compose run --rm client
Greeter client received: Hello, you from host=114c199e6bdb!
Greeter client received: Hello, you from host=114c199e6bdb!
Greeter client received: Hello, you from host=114c199e6bdb!
Greeter client received: Hello, you from host=114c199e6bdb!
Greeter client received: Hello, you from host=114c199e6bdb!
Greeter client received: Hello, you from host=114c199e6bdb!
Greeter client received: Hello, you from host=114c199e6bdb!
Greeter client received: Hello, you from host=114c199e6bdb!
Greeter client received: Hello, you from host=114c199e6bdb!
Greeter client received: Hello, you from host=114c199e6bdb!

Using EDS

Modify /config/active by commenting out one of the serviceX endpoints. Run ./update.sh the proxy running. This will update the eds.yaml created on startup and trigger an update such that only the hosts in the active file are included in the load-balancing`

Outlier Detection

Added outlier detection to the helloworld cluster. This will drop any endpoint if 5 consecutive 5xx are triggered. For demo purposed, we may need to move that to 1. Hosts will comeback into service when they are alive again on a linearly increasing backoff rate; truly dead hosts/endpoints should be ejected from the EDS list by the active health checker performed by the EDS.