Route 53 Routing Policies and Health Checks

Routing policies

One of the key features of Route 53 is the ability to create policies to determine how traffic is routed to the resources that we’ve specified. You’ll need to understand all the routing policies to choose appropriate ones for different scenarios in the exam.

Note: Although the illustrations in this lesson show EC2 instances as targets, the targets can be any resource, like load balancers or on-site servers.

Simple routing

A simple routing policy is used when we have a single resource that we want to route traffic to, like a single web server or ALB.

Points to note:

• The simple routing policy doesn’t work with health checks.
• While the simple routing policy is meant for a single resource, it’s possible to specify multiple values in the same record.
  • Route 53 will return all values as possible targets, and one value is chosen at a random client-side.
  • For alias record types, we can only choose one target value.

Failover routing

The failover routing policy allows us to specify a primary and secondary resource for a domain or subdomain name. Route 53 will route traffic to the primary resource unless it determines that the primary resource is unavailable. Traffic will then be routed to the secondary resource.

The following illustration shows two scenarios. When the primary instance is healthy, Route 53 returns its IP as the target. When the primary instance fails health checks, Route 53 returns the secondary instance IP as the target.

Weighted routing

The weighted routing policy allows us to route traffic to multiple resources in proportions that we specify. For example, we can use a weighted routing policy to route 20% of traffic to one group of servers and 80% to another.

When we create a weighted ...