This is a cluster management block that handles block initialisation and configuration. During the data node startup process, it takes over from theQMGR block and continues the process. It also assists with graceful (planned) shutdowns of data nodes. This block is implemented instorage/ndb/src/kernel/blocks/ndbcntr, which contains these files:
Ndbcntr.hpp: Defines theNdbcntrclass used to implement cluster management functions.NdbcntrInit.cpp: Initializers forNdbcntrdata and records.NdbcntrMain.cpp: Implements methods used for starts, restarts, and reading of configuration data.NdbcntrSysTable.cpp:NDBCNTRcreates and initializes system tables on initial system start. The tables are defined in static structs in this file.