AnsweredAssumed Answered

CLDB High Availability manual vs automatic

Question asked by Arunav on Mar 16, 2017
Latest reply on Mar 20, 2017 by deborah


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've installed CLDB on 3 nodes on a running 5 node MapR(version 5.2) cluster. I've found these 2 links very useful, CLDB failover on a single CLDB cluster and Adding CLDB Role.

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 -C with the CLDB server list for the CLDB to start working.

Now, for the failover, I again ran the -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?



Arunava Addy