NDB Cluster Configuration Files By listing multiple host definitions, it is possible to designate several redundant management servers. An NDB 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. It is also possible to specify in a connection string one or more bind addresses to be used by nodes having multiple network interfaces for connecting to management servers. A bind address consists of a hostname or network address and an optional port number. This enhanced syntax for connection strings is shown here: If a single bind address is used in the connection string  prior  to specifying any management hosts, then this address is used as the default for connecting to any of them (unless overridden for a given management server; see later in this section for an example). For example, the following connection string causes the node to use  198.51.100.242  regardless of the management server to which it connects: bind-address=198.51.100.242, poseidon:1186, perch:1186 If a bind address is specified  following  a management host definition, then it is used only for connecting to that management node. Consider the following connection string: poseidon:1186;bind-address=localhost, perch:1186;bind-address=198.51.100.242 In this case, the node uses  localhost  to connect to the management server running on the host named poseidon  and  198.51.100.242  to connect to the management server running on the host named perch . You can specify a default bind address and then override this default for one or more specific management hosts. In the following example,  localhost  is used for connecting to the management server running on host  poseidon ; since  198.51.100.242  is specified first (before any management server definitions), it is the default bind address and so is used for connecting to the management servers on hosts  perch  and orca : [nodeid= node_id , ] [bind-address= host-definition , ] host-definition [; bind-address= host-definition ] host-definition [; bind-address= host-definition ] [, ...]] host-definition : host_name [: port_number ] bind-address=198.51.100.242,poseidon:1186;bind-address=localhost,perch:1186,orca:2200 There are a number of different ways to specify the connection string: •Each executable has its own command-line option which enables specifying the management server at startup. (See the documentation for the respective executable.) •It is also possible to set the connection string for all nodes in the cluster at once by placing it in a [mysql_cluster]  section in the management server’s  my.cnf  file. •For backward compatibility, two other options are available, using the same syntax: 1. Set the  NDB_CONNECTSTRING  environment variable to contain the connection string. 2. Write the connection string for each executable into a text file named  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 connection string is to set it on the command line or in the my.cnf  file for each executable. 4060