Setup
I have installed three Oracle Linux 7.3. 2 for data nodes, 1 for management and SQL API node. The machines can ping each other, SSH working, "etc/hosts" files are properly filled:
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
172.16.1.101 mysqld_mgmt_1
172.16.1.103 mysql_data_1
172.16.1.104 mysql_data_2
The management node has the following config in the "/var/lib/mysql-cluster/config.ini" file:
# Options affecting ndbd processes on all data nodes:
[NDBD DEFAULT]
NoOfReplicas=2 # Number of replicas
[ndb_mgmd]
# Management process options:
hostname=mysqld_mgmt_1 # Hostname of the manager
datadir=/var/lib/mysql-cluster # Directory for the log files
[ndbd]
hostname=mysql_data_1 # Hostname of the first data node
datadir=/var/lib/mysql-cluster # Remote directory for the data files
ServerPort=50501
[ndbd]
hostname=mysql_data_2 # Hostname of the second data node
datadir=/var/lib/mysql-cluster # Remote directory for the data files
ServerPort=50502
[mysqld]
# SQL node options:
hostname=mysqld_mgmt_1 # In our case the MySQL server/client is on the same Droplet as the cluster manager
The SQL API node (same with the management) has the following config in the "/etc/my.cnf" file:
[mysqld]
ndbcluster # Run NDB storage engine
ndb-connectstring=172.16.1.101
[mysql_cluster]
ndb-connectstring=mysqld_mgmt_1 # IP address for server management node
The two data nodes has the same config file ("/etc/my.cnf") on each node:
[mysqld]
ndbcluster
ndb-connectstring=172.16.1.101
[mysql_cluster]
ndb-connectstring=172.16.1.101 # IP address of Management Node 1
Starting the cluster:
1. management: ndb_mgmd -f /var/lib/mysql-cluster/config.ini
or with a new config to erase the cache:
ndb_mgmd --initial --config-file=/var/lib/mysql-cluster/config.ini
2. data node 1 and 2: ndbd
3. mysql server: service mysql start
Status of the cluster:
[root@mysqld-mgmt-1 ~]# ndb_mgm
-- NDB Cluster -- Management Client --
ndb_mgm> show
Connected to Management Server at: mysqld_mgmt_1:1186
Cluster Configuration
---------------------
[ndbd(NDB)] 2 node(s)
id=2 @172.16.1.103 (mysql-5.6.37 ndb-7.3.18, Nodegroup: 0, *)
id=3 @172.16.1.104 (mysql-5.6.37 ndb-7.3.18, Nodegroup: 0)
[ndb_mgmd(MGM)] 1 node(s)
id=1 @172.16.1.101 (mysql-5.6.37 ndb-7.3.18)
[mysqld(API)] 1 node(s)
id=4 (not connected, accepting connect from 172.16.1.101)
I can login to MySQL from command line on the server node (and from MySQL Workbench as well from another VM):
[root@mysqld-mgmt-1 ~]# mysql -u root -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.6.37-ndb-7.3.18-cluster-gpl MySQL Cluster Community Server (GPL)
Copyright (c) 2000, 2017, 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> show engines;
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| Engine | Support | Comment | Transactions | XA | Savepoints |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| ndbcluster | YES | Clustered, fault-tolerant tables | YES | NO | NO |
| MRG_MYISAM | YES | Collection of identical MyISAM tables | NO | NO | NO |
| MyISAM | YES | MyISAM storage engine | NO | NO | NO |
| ndbinfo | YES | MySQL Cluster system information storage engine | NO | NO | NO |
| CSV | YES | CSV storage engine | NO | NO | NO |
| BLACKHOLE | YES | /dev/null storage engine (anything you write to it disappears) | NO | NO | NO |
| ARCHIVE | YES | Archive storage engine | NO | NO | NO |
| FEDERATED | NO | Federated MySQL storage engine | NULL | NULL | NULL |
| PERFORMANCE_SCHEMA | YES | Performance Schema | NO | NO | NO |
| InnoDB | DEFAULT | Supports transactions, row-level locking, and foreign keys | YES | YES | YES |
| MEMORY | YES | Hash based, stored in memory, useful for temporary tables | NO | NO | NO |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
11 rows in set (0.01 sec)
Testing
I created a sample table without "engine" parameter, just to try things. I wanted to alter table to use ndb engine, but I have the following problem:
mysql> use clusterdb;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> select * from simples;
+----+
| id |
+----+
| 1 |
| 2 |
| 3 |
| 4 |
+----+
4 rows in set (0.00 sec)
mysql> alter table simples engine=ndb;
ERROR 157 (HY000): Could not connect to storage engine
mysql> show warnings;
+---------+------+---------------------------------------------------------------------------------+
| Level | Code | Message |
+---------+------+---------------------------------------------------------------------------------+
| Warning | 1296 | Got error 4009 'Cluster Failure' from NDB. Could not acquire global schema lock |
| Error | 157 | Could not connect to storage engine |
| Error | 1499 | Too many partitions (including subpartitions) were defined |
+---------+------+---------------------------------------------------------------------------------+
3 rows in set (0.00 sec)
mysql> show global status like 'ndb_number_of%';
+--------------------------------+-------+
| Variable_name | Value |
+--------------------------------+-------+
| Ndb_number_of_data_nodes | 2 |
| Ndb_number_of_ready_data_nodes | 0 |
+--------------------------------+-------+
2 rows in set (0.00 sec)
Also, creating table with "engine=ndb" parameter also fails and give the same error. I see the db working with InnoDB engine fine, but I need a fault tolerant (like) database.
