You already know about the Continuent Connector which is the “secret sauce” that routes your application database traffic to the appropriate MySQL data source of your cluster.
Have you ever wondered how the Connector keeps track of the cluster configuration? How it always knows which host is the master (or masters in a Composite Multimaster topology), and which are slaves?
The Short Version
This information is actually held and maintained by the Managers, which monitor and take care of their local MySQL node.
Each one of the Connectors maintains a single connection to one, and only one, manager per data service. In the case of a Composite Multimaster topology, that will be one Manager chosen per site.
The Nitty Gritty
Every 3 seconds, each …[Read more]