WRR with Healthchecking

Perhaps the most common situation for load balancing is where you have multiple servers that can each serve an application. Greenlight, like many other global server load balancers calls this a “pool” of servers. By using a Weighted Round Robin (WRR) resource record, traffic can be distributed across the members of the pool.

Scenario

Let’s say we have several web servers. They all host www.example.com.

How-To

1. Create a Weighted Round Robin resource record
2. Add two pool members, one for www1 and another for www2. Use a Conditional Function Kind
   • For the “Condition”, choose an HTTP Check. Configure it to perform a suitable health check against your server. In the above example, the URLs would be https://www1.example.com and https://www2.example.com
   • For the “If True” and “If False” parts of the Conditional, choose a Constant Function Kind
     • “If True” should be the pool member’s IP address; www1 should have 192.0.2.1 and www2 should have 198.51.100.1
     • “If False” should be empty