Today, I do some expirements for understanding MySQL cluster better.
MySQL cluster works fine:
ndb_mgm> show Connected to Management Server at: localhost:1186 Cluster Configuration [ndbd(NDB)]2 node(s) firstname.lastname@example.org (mysql-5.6.19 ndb-7.3.6, Nodegroup: 0, *) email@example.com (mysql-5.6.19 ndb-7.3.6, Nodegroup: 0) [ndb_mgmd(MGM)]1 node(s) firstname.lastname@example.org (mysql-5.6.19 ndb-7.3.6) [mysqld(API)]1 node(s) email@example.com (mysql-5.6.19 ndb-7.3.6)
Case 1: I turn off management node by killall ndb_mgmd then kill a data node by killall ndbd. I see remain data node is turned off although I don't do anything with it. There is no live data node so sql node is impossible to get or change data.
Case 2: I keep management node live. I kill a data node by killall ndbd. I see the remain data node is sitll living so sql node still works well.
I have a question. Should I keep the management node for controlling data nodes ? I don't read the mysql reference manual mention the similar case.
Thank you in advance.