*** Bug 1869099 has been marked as a duplicate of this bug. ***
Sunil, just grepped ceph-ansible code and it's only used for setting the GRAFANA_API_URL, so the URL used for the iframe-embedded dashboard matches the Fully Qualified Domain Name field defined in the HTTPS certificate. You can of course test that scenario. Additionally, this allows you to define a hostname for Grafana server other than the default one that Ceph-ansible guesses (that may fix situations where the the default IP address for Grafana is not accessible for end-users, like OpenStack deployments).
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory (Red Hat Ceph Storage 4.1 Bug Fix update), and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHBA-2020:4144