ISE in High Availability (HA) mode.. Factors to look upon

Question

We are setting up lab where we have installed 2 ISE on VM.  We  are deploying them in HA mode. While deploying them we are facing error  after registering ISE-2 with Primary ISE-1. Even after periodic refresh  of 'Sync' tab we are getting 'out of sync' Error. 
We have checked certificate which is bound correctly as we could register ISE-2 under primary ISE-1
TIme: Time on all the devices are synched up properly and are in UTC timezone.
What are the factors that play role for HA in ISE. Which things has to look upon while resolving the error.
---Securview Support

Answer 1

Hello,
I went through your query and found some pre-requisite which would help in solving your query:-
Ensure that you have a second ISE node configured with the Administration persona before you can promote it to become your primary Administration ISE node.
•Before you configure the Administration ISE nodes for high availability, we recommend that you obtain a backup of the Cisco ISE configuration from the standalone node that you are going to register as a secondary Administration ISE node.
•Every ISE administrator account is assigned one or more administrative roles. To perform the operations described in the following procedure, you must have one of the following roles assigned: Super Admin or System Admin. See Cisco ISE Admin Group Roles and Responsibilities for more information on the various administrative roles and the privileges associated with each of them.