How to set preferred master for Instant AP from Aruba Central?
Below are the steps to be followed to make an Instant AP to operate as preferred master:
1. Navigate to All Groups > Select the group > Wireless Configuration > Access Points.
2. Click on Actions for the Access Point that need to operate as Preferred Master.
3. Under the BASIC INFO, click on the dropdown for PREFERED MASTER and select Enabled and then click on Save Settings.
4. Instant AP need to be rebooted to operate as Preferred Master.
Below is the screenshot from the Aruba Central: