We tried installing bahmni with FQDN(setting up in /etc/hosts), the following are the observations.
Upgraded from 0.90(with IPs) to 0.91 (with FQDN)
Bahmni installation on primary and secondary is success
Modules look good in smoke testing (not tested odoo)
There are few issues with Nagios
# Sends service unavailability mails even though the service runs
Immediate resolutions taken
Changing FQDN to ips in nagios hosts config resolved the nagios issue.
Things to fix
Making nagios to work with FQDN