By default, Edge-LB uses a round-robin algorithm to distribute network traffic evenly to the appropriate backends. You can change how the workload is distributed by modifying Edge-LB pool configuration settings.

Before you begin

Before you create Edge-LB pools and pool configuration files, you should have DC/OS™ Enterprise cluster nodes installed and ready to use, and have previously downloaded and installed the latest Edge-LB packages.

You must have;

• Edge-LB installed as described in the Edge-LB installation instructions.
• The core DC/OS command-line interface (CLI) installed and configured to communicate with the DC/OS cluster.
• The edgelb command-line interface (CLI) installed.
• An active and properly-configured DC/OS Enterprise cluster, with at least one DC/OS private agent node to run the load-balanced service and at least one DC/OS public agent node for exposing the load-balanced service.

For information about installing Edge-LB packages, see the installation instructions.

Setting weighted values for backend servers

To add relative weights to backend servers, use the pool.haproxy.backend.service.endpoint.miscStr field. The default weight is 1, and the max weight is 256.

In the example below, the /app-v1 service will receive 20 out of every 30 requests, and /app-v2 will receive the remaining 10 out of every 30 requests.

This approach can be used to implement some canary or A/B testing use cases.

{
  "apiVersion": "V2",
  "name": "app-lb",
  "count": 1,
  "haproxy": {
    "frontends": [{
      "bindPort": 80,
      "protocol": "HTTP",
      "linkBackend": {
        "defaultBackend": "default"
      }
    }],
    "backends": [{
      "name": "default",
      "protocol": "HTTP",
      "services": [{
        "marathon": {
          "serviceID": "/app-v1"
        },
        "endpoint": {
          "portName": "web",
          "miscStr": "weight 20"
        }
      },{
        "marathon": {
          "serviceID": "/app-v2"
        },
        "endpoint": {
          "portName": "web",
          "miscStr": "weight 10"
        }
      }]
    }]
  }
}