MySQL Cluster Manager 9.2.0 User Manual

5.4.1 The create cluster Command

create cluster {--package=|-P }package_name
    {--processhosts=|-R }process_host_list cluster_name
    [(--import|-m) cluster_name] [--verbose | -v]

process_host_list:
    process_name[:node_id]@host[,process_name@host[,...]]

process_name:
    {ndb_mgmd|ndbd|ndbmtd|mysqld|ndbapi}

This command creates a cluster to be managed by the MySQL Cluster Manager. However, it does not start the cluster (see Section 5.4.7, “The start cluster Command”).

This command can also be used to create a cluster earmarked specifically as a target for importing another cluster that is not already under MySQL Cluster Manager control, as described later in this section, by employing the --import option. See also Section 4.5, “Importing MySQL NDB Clusters into MySQL Cluster Manager”.

create cluster requires the following arguments:

An additional --verbose option for this command causes create cluster to output extra information as it is executed, as shown later in this section.

The --import option flags the cluster as being created as a target for importing a cluster created outside MySQL Cluster Manager. This option causes the cluster's status to appear as import in the output of show status, as shown here: 

mcm> show status --process newcluster;
+--------+----------+-------+--------+-----------+--------------+
| NodeId | Process  | Host  | Status | Nodegroup | Package      |
+--------+----------+-------+--------+-----------+--------------+
| 1      | ndb_mgmd | alpha | import |           | newpackage   |
| 5      | ndbd     | beta  | import | n/a       | newpackage   |
| 6      | ndbd     | gamma | import | n/a       | newpackage   |
| 10     | mysqld   | delta | import |           | newpackage   |
| 11     | ndbapi   | *     | import |           |              |
+--------+----------+-------+--------+-----------+--------------+
6 rows in set (0.04 sec)

Having the import status causes any of the commands start cluster, restart cluster, start process, and stop process to fail if they are executed before an import cluster command has been executed against this cluster. It is also not possible to execute upgrade cluster on a cluster having processes with import status. Other operations on this cluster continue to be performed normally.

Caution

While it is possible to import into a cluster that was created without this option, it is not advisable, since the cluster is not protected against accidentally performing any of the operations listed previously, which may result in confusing or misleading errors, and possibly other problems. For this reason, it is strongly recommended that you always use the --import option for creating the cluster in such cases.

For more information about importing clusters into MySQL Cluster Manager, including examples, see Section 4.5, “Importing MySQL NDB Clusters into MySQL Cluster Manager”.

Example

Consider the following command issued in the MySQL Cluster Manager client, which creates a cluster named mycluster: 

mcm> create cluster --package=mypackage
  -> --processhosts=ndb_mgmd@flundra,ndbd@tonfisk,ndbd@grindval,mysqld@flundra
  -> mycluster;
+------------------------------+
| Command result               |
+------------------------------+
| Cluster created successfully |
+------------------------------+
1 row in set (7.71 sec)

As defined by the command just shown, mycluster consists of four nodes: a management node on host flundra; two data nodes—one on each of the hosts tonfisk and grindval; and one SQL node, also on host flundra.

Using the --verbose option causes the command to print output similar to that produced by the list processes command, as shown here: 

mcm> create cluster --verbose --package=mypackage
  -> --processhosts=ndb_mgmd@flundra,ndbd@tonfisk,ndbd@grindval,mysqld@flundra
  -> mycluster;
+--------+----------+----------+
| NodeId | Name     | Host     |
+--------+----------+----------+
| 49     | ndb_mgmd | flundra  |
| 1      | ndbd     | tonfisk  |
| 2      | ndbd     | grindval |
| 50     | mysqld   | flundra  |
+--------+----------+----------+
4 rows in set (0.32 sec)

You can also create this cluster in such a way that the mysqld process is permitted to connect to the cluster from any host able to reach the other cluster hosts over the network as shown here: 

mcm> create cluster --package=mypackage
  -> --processhosts=ndb_mgmd@flundra,ndbd@tonfisk,ndbd@grindval,mysqld@*
  -> mycluster;
+------------------------------+
| Command result               |
+------------------------------+
| Cluster created successfully |
+------------------------------+
1 row in set (7.71 sec)
Note

In the case of a “free” ndbapi process, it is not necessary to have the MySQL Cluster Manager software installed on the host where the ndbapi process is running.

Configuration changes to the newly-created cluster can be made using the set command prior to starting the cluster. This is often preferable to doing after the cluster has been started, since set commands used to make configuration changes in a running cluster can require a rolling restart, and rolling restarts of clusters having many nodes or large quantities of data (or both) may take a great deal of time to complete.

Note

When creating a cluster having more than one mysqld process on the same host machine, MySQL Cluster Manager assigns the MySQL default port (3306) to each of them. Therefore, you must assign a unique port for each mysqld process in the cluster.

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