Pour un cluster Aurora donné, 3 endpoints :

• cluster endpoint : pointe toujours sur le master
• reader endpoint : pointe toujours sur un slave
• instance endpoint : permet de pointer spécifiquement une instance donnée. Ne garantit pas que cette instance restera un slave ou un master.

You can determine which DB instance in an Aurora DB cluster that a connection is connected to by checking the innodb_read_only global variable, as shown in the following example.
SHOW GLOBAL VARIABLES LIKE 'innodb_read_only';
The innodb_read_only variable will be set to ON if you are connected to an Aurora Replica and OFF if you are connected to the primary instance.