Integrate with Netflix Eureka

Netflix Eureka is an open-source registry service written in Java by Netflix, and it is essential to Netflix's infrastructure. Netflix Eureka provides a lightweight and reliable solution for service discovery. It utilizes a client-server model where microservices register themselves with the server and other services can dynamically locate them through service resolutions.

This guide will walk you through the process of setting up Netflix Eureka for service discovery, and demonstrate how to integrate it with APISIX to dynamically route and load balance traffic across your microservices.

Prerequisite(s)

• Install Docker.
• Install cURL to send requests to the services for validation.
• Follow the Getting Started Tutorial to start a new APISIX instance in Docker.

Start Eureka Instance

Start a Eureka Docker instance named eureka in the same network as the APISIX instance and expose port 8761 to the same port on the host machine:

docker run \
  --name eureka \
  -d -p 8761:8761 \
  --network=apisix-quickstart-net \
  -e ENVIRONMENT=apisix \
  -e spring.application.name=apisix-eureka \
  -e server.port=8761 \
  -e eureka.instance.ip-address=127.0.0.1 \
  -e eureka.client.registerWithEureka=true \
  -e eureka.client.fetchRegistry=false \
  -e eureka.client.serviceUrl.defaultZone=http://127.0.0.1:8761/eureka/ \
  bitinit/eureka

Start Sample Web Services

In this section, you will start two sample web services based on NGINX.

Create two configuration files, web1.conf and web2.conf, which instruct NGINX to serve static text responses at root:

echo 'worker_processes 1;
error_log stderr notice;
events {
    worker_connections 1024;
}

http {
    variables_hash_max_size 1024;
    access_log off;
    real_ip_header X-Real-IP;
    charset utf-8;

    server {
        listen 80;

        location / {
            return 200 "Application 1 is running";
        }

        location /static/ {
            alias static/;
        }
    }
}' > web1.conf

echo 'worker_processes 1;
error_log stderr notice;
events {
    worker_connections 1024;
}

http {
    variables_hash_max_size 1024;
    access_log off;
    real_ip_header X-Real-IP;
    charset utf-8;

    server {
        listen 80;

        location / {
            return 200 "Application 2 is running";
        }

        location /static/ {
            alias static/;
        }
    }
}' > web2.conf

Start the web services web1 and web2:

docker run -d \
  --name web1 \
  --restart always \
  -v $(pwd)/web1.conf:/etc/nginx/nginx.conf \
  -p 9081:80 \
  --network=apisix-quickstart-net \
  nginx:1.19.0-alpine

docker run -d \
  --name web2 \
  --restart always \
  -v $(pwd)/web2.conf:/etc/nginx/nginx.conf \
  -p 9082:80 \
  --network=apisix-quickstart-net \
  nginx:1.19.0-alpine

❶ Mount web1.conf and web2.conf from the host machine to /etc/nginx/nginx.conf inside the containers.

❷ Map port 80 of the containers to port 9081 and 9082 on the host.

Register Services in Eureka

Save the IP address of your host to an environment variable:

HOST_IP=192.168.31.89   # replace with your host IP

Register two services in Eureka:

curl "http://127.0.0.1:8761/eureka/apps/web" -X POST \
  -H "Content-Type: application/json" \
  -d '{
"instance":{
  "instanceId": "'"$HOST_IP"':9081",
  "hostName": "'"$HOST_IP"'",
  "ipAddr": "'"$HOST_IP"'",
  "port":{
    "$":9081,
    "@enabled":true
    },
  "status": "UP",
  "app": "web",
  "dataCenterInfo": {
    "name": "MyOwn",
    "@class":"com.netflix.appinfo.InstanceInfo$DefaultDataCenterInfo"
    }
  }
}'

curl "http://127.0.0.1:8761/eureka/apps/web" -X POST \
  -H "Content-Type: application/json" \
  -d '{
"instance":{
  "instanceId": "'"$HOST_IP"':9082",
  "hostName": "'"$HOST_IP"'",
  "ipAddr": "'"$HOST_IP"'",
  "port":{
    "$":9082,
    "@enabled":true
    },
  "status": "UP",
  "app": "web",
  "dataCenterInfo": {
    "name": "MyOwn",
    "@class":"com.netflix.appinfo.InstanceInfo$DefaultDataCenterInfo"
    }
  }
}'

Verify if the services are registered successfully:

curl "http://127.0.0.1:8761/eureka/apps/web"

You should see an XML response including information of your services.

Connect Eureka to APISIX

Add Eureka discovery configurations to APISIX's config.yaml configuration file:

docker exec apisix-quickstart /bin/sh -c "echo '
discovery:
  eureka:
    host:
      - "http://eureka:8761"
    prefix: /eureka/
    fetch_interval: 30
    weight: 100
    timeout:
      connect: 2000
      send: 2000
      read: 5000
' >> /usr/local/apisix/conf/config.yaml"

❶ host: address of the Eureka server.

Reload APISIX for configuration changes to take effect:

docker exec apisix-quickstart apisix reload

Create a Route in APISIX

Create a route and configure the upstream to use Consul for service discovery of WEB:

curl "http://127.0.0.1:9180/apisix/admin/routes" -X PUT -d '
{
  "id": "eureka-web-route",
  "uri": "/eureka/web/*",
  "upstream": {
    "service_name": "WEB",
    "discovery_type": "eureka",
    "type": "roundrobin"
  }
}'

An HTTP/1.1 200 OK response verifies that the route is created successfully.

Validate

Generate a few requests to the previously created route:

curl "http://127.0.0.1:9080/eureka/web/"

You should see the responses alternating between the following:

Application 1 is running%

Application 2 is running%

Next Steps

In addition to Eureka, APISIX also supports the integration with HashiCorp Consul, Nacos, and other service discovery platforms (coming soon).