MySQL 8.0 Reference Manual Including MySQL NDB Cluster 8.0

25.4.3 NDB Cluster Configuration Files

Configuring NDB Cluster requires working with two files:

Caching of configuration data.  NDB uses stateful configuration. Rather than reading the global configuration file every time the management server is restarted, the management server caches the configuration the first time it is started, and thereafter, the global configuration file is read only when one of the following conditions is true:

Configuration cache files.  The management server by default creates configuration cache files in a directory named mysql-cluster in the MySQL installation directory. (If you build NDB Cluster from source on a Unix system, the default location is /usr/local/mysql-cluster.) This can be overridden at runtime by starting the management server with the --configdir option. Configuration cache files are binary files named according to the pattern ndb_node_id_config.bin.seq_id, where node_id is the management server's node ID in the cluster, and seq_id is a cache identifier. Cache files are numbered sequentially using seq_id, in the order in which they are created. The management server uses the latest cache file as determined by the seq_id.


It is possible to roll back to a previous configuration by deleting later configuration cache files, or by renaming an earlier cache file so that it has a higher seq_id. However, since configuration cache files are written in a binary format, you should not attempt to edit their contents by hand.

For more information about the --configdir, --config-cache, --initial, and --reload options for the NDB Cluster management server, see Section 25.5.4, “ndb_mgmd — The NDB Cluster Management Server Daemon”.

We are continuously making improvements in NDB Cluster configuration and attempting to simplify this process. Although we strive to maintain backward compatibility, there may be times when introduce an incompatible change. In such cases we try to let NDB Cluster users know in advance if a change is not backward compatible. If you find such a change and we have not documented it, please report it in the MySQL bugs database using the instructions given in Section 1.5, “How to Report Bugs or Problems”.