Perform a test run of the proposed import using import cluster with the --dryrun option. When this option is used, MySQL Cluster Manager checks for mismatched configuration attributes, missing or invalid processes or hosts, missing or invalid PID files, and other errors, and warns of any it finds, but does not actually perform any migration of processes or data.

mcm> import cluster --dryrun newcluster;
ERROR 5302 (00MGR): No access for user mcmd to mysqld 100 in cluster newcluster.
Please verify user access and grants adhere to documented requirements.

We omitted a crucial step earlier: we apparently neglected to create the mcmd superuser account needed on all SQL nodes in the “wild” cluster to bring them under control of MySQL Cluster Manager. In this case, there is only one SQL node, running on delta. Log into this SQL node as the MySQL root user, and create the mcmd account in the mysql client, as shown here:

$> ./mysql -uroot -p
Enter password: ************
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.6.24-ndb-7.4.6 Source distribution

Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> CREATE USER 'mcmd'@'localhost' IDENTIFIED BY 'super';
Query OK, 0 rows affected (0.00 sec)

mysql> GRANT ALL PRIVILEGES ON *.*
    ->     TO 'mcmd'@'localhost' IDENTIFIED BY 'super'
    ->     WITH GRANT OPTION;
Query OK, 0 rows affected (0.00 sec)

mysql> SHOW GRANTS FOR 'mcmd'@'localhost'\G
*************************** 1. row ***************************
Grants for mcmd@localhost: GRANT ALL PRIVILEGES ON *.* TO 'mcmd'@'localhost'
IDENTIFIED BY PASSWORD '*F85A86E6F55A370C1A115F696A9AD71A7869DB81' WITH GRANT OPTION
1 row in set (0.00 sec)

Having corrected this issue on the SQL node, we repeat the dry run in the mcm client:

mcm> import cluster --dryrun newcluster;
ERROR 5310 (00MGR): Process ndb_mgmd 50 reported 6 processes, while 5 processes
are configured for cluster newcluster

This error means that there are one or more cluster processes not accounted for the configuration for the target cluster. Checking the contents of the file /etc/mysql-cluster/config.ini on host alpha, we see that we overlooked a section in it earlier. This section is shown here:

[mysqld]
NodeId=102

To address this discrepancy, we need to add another “free” ndbapi process to newcluster, which we can do by executing the following add process command in the mcm client:

mcm> add process -R ndbapi:102@* newcluster;
+----------------------------+
| Command result             |
+----------------------------+
| Process added successfully |
+----------------------------+
1 row in set (0.38 sec)

You can verify this by checking the output of show status -r command, as shown here:

mcm> show status -r newcluster;
+--------+----------+-------+--------+-----------+------------+
| NodeId | Process  | Host  | Status | Nodegroup | Package    |
+--------+----------+-------+--------+-----------+------------+
| 50     | ndb_mgmd | alpha | import |           | newpackage |
| 5      | ndbd     | beta  | import | n/a       | newpackage |
| 6      | ndbd     | gamma | import | n/a       | newpackage |
| 100    | mysqld   | delta | import |           | newpackage |
| 101    | ndbapi   | *     | import |           |            |
| 102    | ndbapi   | *     | import |           |            |
+--------+----------+-------+--------+-----------+------------+
6 rows in set (0.11 sec)

Now we can run another test, using import cluster with the --dryrun as we did previously:

mcm> import cluster --dryrun newcluster;

Continue to correct any errors or other discrepancies found using --dryrun, repeating the dry run shown in the previous step to ensure that no errors were missed. The following list contains some common errors you may encounter, and their likely causes:

When import cluster --dryrun no longer warns of any errors, you can perform the import with the import cluster command, this time omitting the --dryrun option.