Configuring per-route options

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By default, communication between Gorouter and backends is configured via general settings at the platform level.

This topic describes how to specify per-route Gorouter options scoped at the application level. This greater granularity lets developers tailor optimal routing behavior for applications’ unique load profiles or other requirements.

Gorouter supports the following per-route option, described in the section below:

• loadbalancing: Configures the load balancing algorithm used by Gorouter for this particular route.
  • Settings: round-robin, least-connections.

loadbalancing: Configure Gorouter’s Load Balancing Algorithm

The per-route option loadbalancing allows configuring the load balancing algorithm, which defines how the load is distributed between Gorouters and backends.

This option supports two settings for load balancing:

• round-robin distributes the load evenly across all available backends
• least-connections directs traffic to the backend with the fewest active connections at any given time, optimizing resource utilization

Configure Load Balancing in an App Manifest

To configure per-route load balancing for an application that has not yet been pushed:

1. In the application manifest, include a route definition with an options: loadbalancing attribute set to round-robin or least-connections. For example:

   ---
   applications:
   - name: MY-APP
     routes:
       - route: MY-APP.EXAMPLE.COM
          options:
            loadbalancing: least-connections
   

   Where MY-APP is the name of your app and MY-APP.EXAMPLE.COM is the route you want to map to your app.

2. Push the app with the manifest:

   cf push -f manifest.yml
   

3. To confirm the setting, query the routes API endpoint for the app’s route:

   cf curl /v3/routes/?hosts=MY-APP
   

   Where MY-APP is the host attribute of the route. The response lists the chosen loadbalancing algorithm setting:

      "options": {
        "loadbalancing": "least-connections"
      }
   

Change Load Balancing of an Existing App

To change the per-route loadbalancing setting of an app that has already been pushed, cf curl the /v3/routes API. For example, to change an app route’s algorithm from least-connections to round-robin:

1. Execute a PATCH request to the targeted API endpoint:

   cf curl /v3/routes/GUID -X PATCH -H "Content-type: application/json" \
     -d '{
      "options": {
        "loadbalancing": "round-robin"
      }
    }'
   

   Where GUID is the unique identifier for the route.

2. To confirm the setting, query the routes API endpoint for the route:

   cf curl /v3/routes/GUID
   

Where GUID is the unique identifier for the route. The response lists the new round-robin setting:

   "options": {
     "loadbalancing": "round-robin"
   }