Custom endpoints for Amazon Aurora

A custom endpoint for an Aurora cluster represents a set of DB instances that you choose. When you connect to the endpoint, Aurora performs connection balancing and chooses one of the instances in the group to handle the connection. You define which instances this endpoint refers to, and you decide what purpose the endpoint serves.

An Aurora DB cluster has no custom endpoints until you create one. You can create up to five custom endpoints for each provisioned Aurora cluster or Aurora Serverless v2 cluster. You can't use custom endpoints for Aurora Serverless v1 clusters.

The custom endpoint provides balanced database connections based on criteria other than the read-only or read/write capability of the DB instances. For example, you might define a custom endpoint to connect to instances that use a particular AWS instance class or a particular DB parameter group. Then you might tell particular groups of users about this custom endpoint. For example, you might direct internal users to low-capacity instances for report generation or ad hoc (one-time) querying, and direct production traffic to high-capacity instances.

Because the connection can go to any DB instance that is associated with the custom endpoint, we recommend that you make sure that all the DB instances within that group share some similar characteristic. Doing so ensures that the performance, memory capacity, and so on, are consistent for everyone who connects to that endpoint.

This feature is intended for advanced users with specialized kinds of workloads where it isn't practical to keep all the Aurora Replicas in the cluster identical. With custom endpoints, you can predict the capacity of the DB instance used for each connection. When you use custom endpoints, you typically don't use the reader endpoint for that cluster.

The following example illustrates a custom endpoint for a DB instance in an Aurora MySQL DB cluster.

myendpoint.cluster-custom-c7tj4example.us-east-1.rds.amazonaws.com:3306

You use custom endpoints to simplify connection management when your cluster contains DB instances with different capacities and configuration settings.

Previously, you might have used the CNAMES mechanism to set up Domain Name Service (DNS) aliases from your own domain to achieve similar results. By using custom endpoints, you can avoid updating CNAME records when your cluster grows or shrinks. Custom endpoints also mean that you can use encrypted Transport Layer Security/Secure Sockets Layer (TLS/SSL) connections.

Instead of using one DB instance for each specialized purpose and connecting to its instance endpoint, you can have multiple groups of specialized DB instances. In this case, each group has its own custom endpoint. This way, Aurora can perform connection balancing among all the instances dedicated to tasks such as reporting or handling production or internal queries. The custom endpoints distribute connections across instances passively, using DNS to return the IP address of one of the instances randomly. If one of the DB instances within a group becomes unavailable, Aurora directs subsequent custom endpoint connections to one of the other DB instances associated with the same endpoint.