After some time of experiments the Calamari / Romana console lost management connection to SES cluster. The Romana web-GUI reports every management form as follows:
New Calamari Installation
This appears to be the first time you have started Calamari and there are no clusters currently configured.
7 Ceph servers are connected to Calamari, but no Ceph cluster has been created yet. Please use ceph-deploy to create a cluster; please see the SUSE Enterprise Storage documentation for more details.
However, the Ceph cluster is in good health:
admin:~ # ceph -w
cluster f4cbac17-f67d-4a05-b0df-24b5b056143a
health HEALTH_OK
monmap e2: 3 mons at {mon01=,mon02=,mon03=}
election epoch 4176, quorum 0,1,2 mon01,mon02,mon03
fsmap e330: 1/1/1 up {0=mds01=up:active}
osdmap e197: 4 osds: 4 up, 4 in
flags sortbitwise
pgmap v319416: 208 pgs, 14 pools, 2048 MB data, 715 objects
4272 MB used, 16163 MB / 20435 MB avail
208 active+clean
client io 35261 B/s rd, 1647 B/s wr, 11 op/s rd, 3 op/s wr
The main question is: "how to bring the management to operable state?"

Recipe #1: reboot everything. No effect.

Recipe #2: try to reinitialize Calamari databases. No effect.
calamari-ctl clear –-yes-i-am-sure
calamari-ctl initialize
Recipe #3: deinstall and remove data folders for Calamari / Romana, as described at manual tip, reinstall both and reconnect cluster nodes. No effect.

Recipe #4: reinstall the Calamary server from scratch. Left as a last resort.

Thus, the related question is: "how to troubleshoot the Calamari management?"

According to the video, this task seems not simple...