1. Do I need to run the setup-ssg-3.5.sh script in both of the nodes or is that only required on the primary node of the cluster?
A: yes
2. Do I need to publish portalman and key management services on both the nodes?
A: Once you create gateway cluster, replication , publishing this on one node will replicate to the other node DB as well
3. While running the config_portal.sh do I need to give my gateway cluster hostname (which is load balancer hostname) for the field where it asks for the gateway host name?
A: Yes, if you are using Load Balancer, make sure that LB is not terminating SSL
4. Do I need to configure the API portal metrics synchronization utility on both instances of the Gateway?
A:No
Configure the Portal Metrics Synchronization Utility - CA API Developer Portal - 3.1 - CA Technologies Documentation
Configure the Portal Metrics Synchronization Utility
Last update June 16, 2015
The Portal Metrics Sync Utility pushes metrics data from the CA API Gateway database to the API Portal database. The configuration is done as a privileged (root) user on the command line. Knowledge of Linux commands is required.
Before proceeding, make sure an API Portal instance has been configured. For more information, see "Install the API Portal".
Note: For clustered Gateways, the API Portal Metrics Synchronization Utility should only be installed on one Gateway node of the cluster.