You need to select which of the instances in
your system will be master instances.
If you are installing a multi-instance system, the system must have either one or three master instances, regardless of the total number of instances it includes.
Important:
- For a production system, use three master instances.
- You cannot add master instances to a system after it's installed. You can, however, add any number of worker instances.
If you are deploying a single-instance system, that instance will automatically be configured as a master instance and run all services for the system.