7.81 Simple routing strategy

We start the routing-policy series with the simple strategy. A client browser issues a DNS request to Route 53, which returns a record (typically an A record) mapping the name to an IP — for example 1.2.3.4. You use simple routing when you want to direct all traffic to a single resource. Key constraint: no health checks can be attached to a simple routing record.

If the record contains multiple values, Route 53 returns all of them and the resolver picks one at random. So you cannot guarantee which endpoint a client will land on with this strategy — it is essentially round-robin at the client side.

Hands-on in the console

  • Create a record, choose Simple routing.
  • Name it (for example simple.mon-domaine.com), set TTL to 60 seconds, type A.
  • Define the record by entering the Ireland instance IP.
  • Save — the record is created.

Hitting the URL serves the Ireland instance. To turn this into client-side load balancing, edit the record and add a second IP — for example the Paris instance. Save and wait for the 60-second TTL to expire. From that point on, every refresh has roughly a 50/50 chance of returning the Ireland or the Paris instance. The user gets a different backend depending on which IP the resolver hands out. That is the whole simple routing strategy: one record name, one or more endpoints, random selection, no health awareness.

Summary

This lesson covers AWS Route 53's simple routing strategy, which directs traffic to a single resource or randomly among multiple resources when multiple IP addresses are specified. The strategy does not support health checks and uses a TTL (Time To Live) to control DNS cache duration. The instructor demonstrates setting up simple routing records in Route 53 console and testing how the DNS resolver returns different IP addresses, allowing load distribution across instances in different geographic regions.

Key points

  • Simple routing strategy routes traffic to a single resource or randomly picks from multiple IP addresses when several are defined
  • Health checks cannot be associated with simple routing strategy records
  • TTL (Time To Live) is set to 60 seconds to control how long DNS responses are cached by clients
  • When multiple IP addresses are configured, clients randomly choose one of the returned responses with equal probability
  • Simple routing can distribute traffic across instances in different geographic locations (e.g., Ireland and Paris) without active health monitoring
  • DNS resolution demonstrates a 50/50 chance of being routed to different instances when two IPs are configured

FAQ

What is simple routing strategy in AWS Route 53?

Simple routing strategy is a DNS routing policy in Route 53 that directs traffic to a single resource or, when multiple IP addresses are specified, randomly distributes traffic among them. It is the simplest routing option but does not support health checks.

Can you use health checks with simple routing strategy?

No, health checks cannot be associated with simple routing strategy records. This means Route 53 will return all configured IP addresses regardless of whether the underlying resources are healthy.

How does simple routing work when multiple IP addresses are configured?

When multiple IP addresses are defined for a simple routing record, Route 53 returns all of them in the DNS response. The client randomly selects one of the returned IP addresses to establish the connection, resulting in load distribution across the resources.