I have configured HA here with details below;
SSO Integration
- Client provides the SSO portal, operator log in. They can access all applications that they have the right. For Pega we have create custom authentication service called "AISSSOPORTALAuthentication" to support this requirement, the incoming servlet from SSO portal include the token like this;

"​S19kZ6yCDKdc50vCNfTplKYhJ5hGSn2GhCG67YmCpgh0k17m0lwy!2019907939!1505374722937,kasawan,1457,3243,null"

Note: kasawan is user name in this case.

Inside AISSSOPORTALAuthentication we have the activity named "AISSSOPORTALAuthentication", it split above token with "," and check the second split string "kasawan" with existing operator in Pega, if Pega found "kasawan" is defined in Pega, it will open the portal for kasawan.

Then we implemented HA, we tried to test the crash recovery especially the re-login, client prefer seamless experience with the following scenario;

- once node #1 get crashed, F5 load balancer will route the request from operator to another node (node #2 for example).

Note: Preferably operator should continue to work without re-login.

What we found out once F5 load balancer route the request to node 2, Pega cannot find existing operator session, it invokes the AISSSOPORTALAuthentication service again but this time no token provided as request from SSO Portal.

Question:

Does Pega has any pages or other ways to refer to the operator name who send request from crashed node? If we know that pages/servlet parameters then we will update our custom activity and make it seamless for user when node crashed scenario occurred.

Note: I have attached the PPT for this scenario.