16.6.2. Commands in the Management Client
In addition to the central configuration file, a cluster may
also be controlled through a command-line interface available
through the management client ndb_mgm. This
is the primary administrative interface to a running cluster.
Commands for the event logs are given in
Section 16.6.3, “Event Reports Generated in MySQL Cluster”. commands for
creating backups and restoring from backup are provided in
Section 16.6.5, “On-line Backup of MySQL Cluster”.
The management client has the following basic commands. In the
listing that follows, node_id denotes
either a database node ID or the keyword ALL,
which indicates that the command should be applied to all of the
cluster's data nodes.
-
HELP
Displays information on all available commands.
-
SHOW
Displays information on the cluster's status.
Note: In a cluster where
multiple management nodes are in use, this command displays
information only for data nodes that are actually connected
to the current management server.
-
node_id START
Starts the data node identified by
node_id (or all data nodes).
-
node_id STOP
Stops the data node identified by
node_id (or all data nodes).
-
node_id RESTART [-N]
[-I]
Restarts the data node identified by
node_id (or all data nodes).
-
node_id STATUS
Displays status information for the data node identified by
node_id (or for all data nodes).
-
ENTER SINGLE USER MODE
node_id
Enters single-user mode, whereby only the MySQL server
identified by the node ID node_id
is allowed to access the database.
-
EXIT SINGLE USER MODE
Exits single-user mode, allowing all SQL nodes (that is, all
running mysqld processes) to access the
database.
-
QUIT
Terminates the management client.
-
SHUTDOWN
Shuts down all cluster nodes, except for SQL nodes, and
exits.
