Failover on multi-node systems triggered only on CMAPI absence

When a multi-node system is installed with GlusterFS and a node goes away, CMAPI performs a fail-over. However, the actual conditions are not well documented and this leaves room for wrong interpretations.

It seems that CMAPI will trigger the fail-over only when the peer CMAPI goes away (network cut, power off the peer etc.). It will NOT, however, trigger it on CS process missing or crashed (think systemctl stop mariadb-cloumnstore). As a minimum, this needs to be well documented, which currently it is not (if possible, push for some documentation update). At best, CMAPI should be able to conduct a fail-over if the peer node is unable to process queries for whatever reason (even if its local CMAPI is still up) - if possible, convert this then to a feature request.