I was trying to explore the CLDB HA options with the Enterprise(M5) trial License. I noticed that after applying the Enterprise license, I can choose multiple servers to install CLDB on. This option was disabled with the M3 license.
I also noticed the fact while installing the CLDB services with MCS, that CLDB had to be installed on a odd number of nodes.
I initially had a running cluster with 1 CLDB node. Then I installed the CLDB service on another 2 nodes. After the installations are done(I did a warden restart), the Master CLDB has not been chosen automatically. And hence, the CLDB was not recognised.
[root@ip-172-31-50-195 ~]# maprcli node listcldbzks
ERROR (10009) - Couldn't connect to the CLDB service
I had to run the configure.sh -C with the CLDB server list for the CLDB to start working.
Now, for the failover, I again ran the configure.sh -C and it worked perfectly. My questions are:
1. Why the odd number of nodes? Does it mean there's a automatic leader selection process in place?
2. Is there a way the CLDB fails over automatically?