Ceph - Launching Calamari web UI after a restart of admin/Calamari node produces Server Error (500)

Issue

• After a reboot/restart of admin/Calamari node the Calmari web UI will not start and produces a Server Error (500).
  Cthulhu log files (/var/log/calamari/cthulhu.log) will show:

2016-03-08 08:49:40,252 - ERROR - cthulhu Recovery failed
2016-03-08 08:49:41,681 - ERROR - cthulhu Recovery failed
2016-03-08 08:49:44,116 - ERROR - cthulhu Recovery failed
2016-03-08 08:49:48,421 - ERROR - cthulhu Recovery failed

Supervisord reports Cthulhu in the following state:

[root@admin ~]# supervisorctl 
carbon-cache                     RUNNING    pid 1010, uptime 0:06:14
cthulhu                          FATAL      Exited too quickly (process log may have details)