三台linux 1、配置yum源
[root@localhost ~]# vim /etc/yum.repos.d/galera.repo
[mysql]
baseurl=https://mirrors.tuna.tsinghua.edu.cn/mariadb/mariadb-5.5.64/yum/centos7-amd64/
gpgcheck=0
enabled=1
2、安装软件
所有要实现galera的都需要安装，MariaDB-Galera-server会自动把mariadb-server替换掉
[root@localhost ~]# yum -y install MariaDB-Galera-server
3、配置文件
[root@localhost ~]# vim /etc/my.cnf.d/server.cnf
[galera]
wsrep_provider=/usr/lib64/galera/libgalera_smm.so #库文件路径
wsrep_cluster_address="gcomm://192.168.2.6,192.168.2.16,192.168.2.16" #gcomm协议，集群主机
binlog_format=row
4、同步配置文件
[root@localhost ~]# scp /etc/my.cnf.d/server.cnf 192.168.2.16:/etc/my.cnf.d/
[root@localhost ~]# scp /etc/my.cnf.d/server.cnf 192.168.2.26:/etc/my.cnf.d/
5、首次启动，需要初始化集群，在其中一个节点上执行，然后再正常启动其他节点
[root@localhost ~]# service mysql start --wsrep-new-cluster #（脚本启动方法）
Starting MariaDB.190509 23:16:39 mysqld_safe Logging to '/var/log/mariadb/mariadb.log'.
190509 23:16:39 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
.... SUCCESS!
[root@localhost ~]# service mysql start
Starting MariaDB.190509 23:18:37 mysqld_safe Logging to '/var/log/mariadb/mariadb.log'.
190509 23:18:37 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
....SST in progress, setting sleep higher.. SUCCESS!
root@localhost ~]# service mysql start
Starting MariaDB.190509 23:19:07 mysqld_safe Logging to '/var/log/mariadb/mariadb.log'.
190509 23:19:07 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
...SST in progress, setting sleep higher. SUCCESS!
6、一台机器执行安全脚本（会同步部分数据库信息）
[root@localhost ~]# mysql_secure_installation
7、测试同步
主机1：
MariaDB [(none)]> create database db1;
主机2：
MariaDB [(none)]> show databases;
主机3：
MariaDB [(none)]> show databases;
主机2：
MariaDB [(none)]> create database db1;
ERROR 1007 (HY000): Can't create database 'db1'; database exists
主机3：
MariaDB [(none)]> create database db1;
ERROR 1007 (HY000): Can't create database 'db1'; database exists
测试成功
8、查看集群中相关系统变量和状态变量
MariaDB [(none)]> show variables like 'wsrep_%'\G;
MariaDB [(none)]> show status like 'wsrep_%';
MariaDB [(none)]> show status like 'wsrep_cluster_size';
