With the exception of the MySQL Cluster management server (ndb_mgmd), each node that is part of a MySQL Cluster requires a connectstring that points to the management server's location. This connectstring is used in establishing a connection to the management server as well as in performing other tasks depending on the node's role in the cluster. The syntax for a connectstring is as follows:
node_id is an integer larger than 1 which
identifies a node in
host_name is a string representing a
valid Internet host name or IP address.
port_number is an integer referring
to a TCP/IP port number.
example 1 (long): "nodeid=2,myhost1:1100,myhost2:1100,192.168.0.3:1200" example 2 (short): "myhost1"
localhost:1186 is used as the default
connectstring value if none is provided. If
port_num is omitted from the
connectstring, the default port is 1186.
Prior to MySQL 4.1.8, the default port was 2200.
By listing multiple host definitions, it is possible to designate several redundant management servers. A MySQL Cluster data or API node attempts to contact successive management servers on each host in the order specified, until a successful connection has been established.
There are a number of different ways to specify the connectstring:
Each executable has its own command-line option which enables specifying the management server at startup. (See the documentation for the respective executable.)
Beginning with MySQL 4.1.8, it is also possible to set the
connectstring for all nodes in the cluster at once by
placing it in a
in the management server's
For backward compatibility, two other options are available, using the same syntax:
variable to contain the connectstring.
Write the connectstring for each executable into a text
Ndb.cfg and place this
file in the executable's startup directory.
However, these are now deprecated and should not be used for new installations.
The recommended method for specifying the connectstring is to
set it on the command line or in the
file for each executable.
The maximum length of a connectstring is 1024 characters.