设置
我已经安装了三个Oracle Linux 7.3。2 个用于数据节点，1 个用于管理和 SQL API 节点。机器可以互相 ping 通，SSH 工作，“etc/hosts”文件被正确填充：
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
管理节点在“/var/lib/mysql-cluster/config.ini”文件中有如下配置：
# 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
SQL API 节点（与管理相同）在“/etc/my.cnf”文件中具有以下配置：
[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
两个数据节点在每个节点上都有相同的配置文件（“/etc/my.cnf”）：
[mysqld]
ndbcluster
ndb-connectstring=172.16.1.101
[mysql_cluster]
ndb-connectstring=172.16.1.101 # IP address of Management Node 1
启动集群：
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
集群状态：
[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)
我可以从服务器节点上的命令行登录到 MySQL（以及从 MySQL Workbench 以及从另一个 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)
测试
我创建了一个没有“引擎”参数的示例表，只是为了尝试。我想更改表以使用 ndb 引擎，但我有以下问题：
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)
此外，使用“engine=ndb”参数创建表也会失败并给出相同的错误。我看到数据库可以与 InnoDB 引擎一起正常工作，但我需要一个容错（类似）数据库。