DNS endpoints - Amazon Aurora MySQL Database Administrator’s Handbook

DNS endpoints

An Aurora DB cluster consists of one or more instances and a cluster volume that manages the data for those instances. There are two types of instances:

  • Primary instance – Supports read and write statements. Currently, there can be one primary instance per DB cluster.

  • Aurora Replica – Supports read-only statements. A DB cluster can have up to 15 Aurora Replicas. The Aurora Replicas can be used for read scaling, and are automatically used as failover targets in case of a primary instance failure.

Amazon Aurora supports the following types of Domain Name System (DNS) endpoints:

  • Cluster endpoint – Connects you to the primary instance and automatically follows the primary instance in case of failover, that is, when the current primary instance is demoted and one of the Aurora Replicas is promoted in its place.

  • Reader endpoint – Includes all Aurora Replicas in the DB cluster under a single DNS CNAME. You can use the reader endpoint to implement DNS-based random assignment of instance IP addresses to new read-only connections.

  • Instance endpoint – Each instance in the DB cluster has its own individual endpoint. You can use this endpoint to connect directly to a specific instance.

  • Custom endpoints – User-defined DNS endpoints containing a selected group of instances from a given cluster.

For more information, refer to the Overview of Amazon Aurora page.