# MySQL Cluster setup and MaxScale configuration Massimiliano Pinto Last Updated: 1st August 2014 ## Contents ## Document History
Date Change Who
31st July 2014 Initial version Massimiliano Pinto
## Overview The document covers the MySQL Cluster 7.2.17 setup and MaxScale configuration in order to load balancing the SQL nodes access. ## MySQL Cluster setup The MySQL Cluster 7.2.17 setup is based on two virtual servers with Linux Centos 6.5 - server1: NDB Manager process SQL data node1 MySQL 5.5.38 as SQL node1 - server2: SQL data node2 MySQL 5.5.38 as SQL node2 Cluster configuration file is /var/lib/mysql-cluster/config.ini, copied on all servers [ndbd default] NoOfReplicas=2 DataMemory=60M IndexMemory=16M [ndb_mgmd] hostname=178.62.38.199 id=21 datadir=/var/lib/mysql-cluster [mysqld] hostname=178.62.38.199 [mysqld] hostname=162.243.90.81 [ndbd] hostname=178.62.38.199 [ndbd] hostname=162.243.90.81 Note, it’s possible to specify all node ids and datadir as well for each cluster component Example: [ndbd] hostname=162.243.90.81 id=43 datadir=/usr/local/mysql/data and /etc/my.cnf, copied as well in all servers [mysqld] ndbcluster ndb-connectstring=178.62.38.199 innodb_buffer_pool_size=16M [mysql_cluster] ndb-connectstring=178.62.38.199 ## Startup of MySQL Cluster Each cluster node process must be started separately, and on the host where it resides. The management node should be started first, followed by the data nodes, and then finally by any SQL nodes: - On the management host, server1, issue the following command from the system shell to start the management node process: [root@server1 ~]# ndb_mgmd -f /var/lib/mysql-cluster/config.ini - On each of the data node hosts, run this command to start the ndbd process: [root@server1 ~]# ndbd —-initial -—initial-start [root@server2 ~]# ndbd —-initial -—initial-start - On each SQL node start the MySQL server process: [root@server1 ~]# /etc/init.d/mysql start [root@server2 ~]# /etc/init.d/mysql start ## Check the cluster status If all has gone well, and the cluster has been set up correctly, the cluster should now be operational. It’s possible to test this by invoking the ndb_mgm management node client. The output should look like that shown here, although you might see some slight differences in the output depending upon the exact version of MySQL that you are using: [root@server1 ~]# ndb_mgm -- NDB Cluster -- Management Client -- ndb_mgm> show Connected to Management Server at: 178.62.38.199:1186 Cluster Configuration --------------------- [ndbd(NDB)] 2 node(s) id=24 @178.62.38.199 (mysql-5.5.38 ndb-7.2.17, Nodegroup: 0, *) id=25 @162.243.90.81 (mysql-5.5.38 ndb-7.2.17, Nodegroup: 0) [ndb_mgmd(MGM)] 1 node(s) id=21 @178.62.38.199 (mysql-5.5.38 ndb-7.2.17) [mysqld(API)] 2 node(s) id=22 @178.62.38.199 (mysql-5.5.38 ndb-7.2.17) id=23 @162.243.90.81 (mysql-5.5.38 ndb-7.2.17) ndb_mgm> The SQL node is referenced here as [mysqld(API)], which reflects the fact that the mysqld process is acting as a MySQL Cluster API node. ## Working with NDBCLUSTER engine in MySQL - First create a table with NDBCLUSTER engine: [root@server1 ~]# mysql mysql> CREATE TABLE `t1` ( `a` int(11) DEFAULT NULL ) ENGINE=NDBCLUSTER; Query OK, 0 rows affected (3.28 sec) mysql> show create table t1; +------- +-------------------------------------------------------------------------------------------+ | Table | Create Table | +-------+-------------------------------------------------------------------------------------------+ | t1 | CREATE TABLE `t1` ( `a` int(11) DEFAULT NULL ) ENGINE=ndbcluster DEFAULT CHARSET=latin1 | +-------+-------------------------------------------------------------------------------------------+ 1 row in set (0.01 sec) - Just add a row in the table: mysql> insert into test.t1 values(11); Query OK, 1 row affected (0.15 sec) - Select the current number of rows: mysql> select count(1) from t1; +----------+ | count(1) | +----------+ | 1 | +----------+ 1 row in set (0.07 sec) - The same from the MySQL client pointing to SQL node on server2 [root@server2 ~]# mysql mysql> select count(1) from test.t1; +----------+ | count(1) | +----------+ | 1 | +----------+ 1 row in set (0.08 sec) ## Configuring MaxScale for connection load balancing of SQL nodes Add these sections in maxscale.cnf config file: [Cluster Service] type=service router=readconnroute router_options=ndb servers=server1,server2 user=test passwd=test version_string=5.5.37-CLUSTER [Cluster Listener] type=listener service=Cluster Service protocol=MySQLClient port=4906 [NDB Cluster Monitor] type=monitor module=ndbclustermon servers=server1,server2 user=monitor passwd=monitor monitor_interval=8000 [server1] #SQL node1 type=server address=127.0.0.1 port=3306 protocol=MySQLBackend [server2] #SQL node2 type=server address=162.243.90.81 port=3306 protocol=MySQLBackend Assuming MaxScale is installed in server1, start it [root@server1 ~]# cd /usr/bin [root@server1 bin]# ./maxscale -c ../ Using the debug interface it’s possible to check the status of monitored servers MaxScale> show monitors Monitor: 0x387b880 Name: NDB Cluster Monitor Monitor running Sampling interval: 8000 milliseconds Monitored servers: 127.0.0.1:3306, 162.243.90.81:3306 MaxScale> show servers Server 0x3873b40 (server1) Server: 127.0.0.1 Status: NDB, Running Protocol: MySQLBackend Port: 3306 Server Version: 5.5.38-ndb-7.2.17-cluster-gpl Node Id: 22 Master Id: -1 Repl Depth: 0 Number of connections: 0 Current no. of conns: 0 Current no. of operations: 0 Server 0x3873a40 (server2) Server: 162.243.90.81 Status: NDB, Running Protocol: MySQLBackend Port: 3306 Server Version: 5.5.38-ndb-7.2.17-cluster-gpl Node Id: 23 Master Id: -1 Repl Depth: 0 Number of connections: 0 Current no. of conns: 0 Current no. of operations: 0 It’s now possible to run basic tests with the read connection load balancing for the two configured SQL nodes (1) test MaxScale load balancing requesting the Ndb_cluster_node_id variable: [root@server1 ~]# mysql -h 127.0.0.1 -P 4906 -u test -ptest -e "SHOW STATUS LIKE 'Ndb_cluster_node_id'" +---------------------+-------+ | Variable_name | Value | +---------------------+-------+ | Ndb_cluster_node_id | 23 | +---------------------+-------+ [root@server1 ~]# mysql -h 127.0.0.1 -P 4906 -u test -ptest -e "SHOW STATUS LIKE 'Ndb_cluster_node_id'" +---------------------+-------+ | Variable_name | Value | +---------------------+-------+ | Ndb_cluster_node_id | 22 | +---------------------+-------+ The MaxScale connection load balancing is working. (2) test a select statement on an NBDBCLUSTER table, database test and table t1 created before: [root@server1 ~] mysql -h 127.0.0.1 -P 4906 -utest -ptest -e "SELECT COUNT(1) FROM test.t1" +----------+ | COUNT(1) | +----------+ | 1 | +----------+ (3) test an insert statement mysql -h 127.0.0.1 -P 4906 -utest -ptest -e "INSERT INTO test.t1 VALUES (19)" (4) test again the select and check the number of rows [root@server1 ~] mysql -h 127.0.0.1 -P 4906 -utest -ptest -e "SELECT COUNT(1) FROM test.t1" +----------+ | COUNT(1) | +----------+ | 2 | +----------+