1. 添加hosts

   cat /etc/hosts
   192.168.100.17  mariadb01
   192.168.100.17  mariadb02

2. 添加yum源

   cat /etc/yum.repos.d/mariadb.repo 
   [mariadb]
   name=mariadb
   baseurl=http://yum.mariadb.org/10.3.9/centos7-amd64/
   gpgcheck=0
   enabled=1

3. 安装数据库软件包

   yum install MariaDB-server

4. 备份数据库配置文件，并修改/etc/my.cnf.d/server.cnf配置文件
   mariadb01配置：

   [galera]
   wsrep_on=ON
   wsrep_provider=/usr/lib64/galera/libgalera_smm.so
   wsrep_cluster_address="gcomm://192.168.100.17:4567,192.168.100.18:4567"
   wsrep_node_name= mariadb01
   wsrep_node_address=192.168.100.17
   binlog_format=row
   default_storage_engine=InnoDB
   innodb_autoinc_lock_mode=2
   wsrep_slave_threads=1
   innodb_flush_log_at_trx_commit=0
   innodb_buffer_pool_size=120M
   wsrep_sst_method=rsync
   wsrep_causal_reads=ON

   mariadb02配置：

   [galera]
   wsrep_on=ON
   wsrep_provider=/usr/lib64/galera/libgalera_smm.so
   wsrep_cluster_address="gcomm://192.168.100.18:4567,192.168.100.17:4567"
   wsrep_node_name= mariadb02
   wsrep_node_address=192.168.100.18
   binlog_format=row
   default_storage_engine=InnoDB
   innodb_autoinc_lock_mode=2
   wsrep_slave_threads=1
   innodb_flush_log_at_trx_commit=0
   innodb_buffer_pool_size=120M
   wsrep_sst_method=rsync
   wsrep_causal_reads=ON

5. 配置iptables规则

   iptables -I INPUT 1 -p tcp -m multiport --dport 3306,4567 -j ACCEPT
   service iptables save

6. 第一个节点第一次启动

   galera_new_cluster
   systemctl enable mariadb

   其他节点启动

   systemctl enable mariadb
   systemctl start mariadb

7. 查看集群状态

   MariaDB [(none)]> show status like "wsrep%";
   +------------------------------+-----------------------------------------+
   | Variable_name                | Value                                   |
   +------------------------------+-----------------------------------------+
   | wsrep_apply_oooe             | 0.000000                                |
   | wsrep_apply_oool             | 0.000000                                |
   | wsrep_apply_window           | 0.000000                                |
   | wsrep_causal_reads           | 3                                       |
   | wsrep_cert_deps_distance     | 0.000000                                |
   | wsrep_cert_index_size        | 0                                       |
   | wsrep_cert_interval          | 0.000000                                |
   | wsrep_cluster_conf_id        | 10                                      |
   | wsrep_cluster_size           | 2                                       |
   | wsrep_cluster_state_uuid     | 7425394a-d931-11e8-86a0-d29d9b403794    |
   | wsrep_cluster_status         | Primary                                 |
   | wsrep_commit_oooe            | 0.000000                                |
   | wsrep_commit_oool            | 0.000000                                |
   | wsrep_commit_window          | 0.000000                                |
   | wsrep_connected              | ON                                      |
   | wsrep_desync_count           | 0                                       |
   | wsrep_evs_delayed            |                                         |
   | wsrep_evs_evict_list         |                                         |
   | wsrep_evs_repl_latency       | 0/0/0/0/0                               |
   | wsrep_evs_state              | OPERATIONAL                             |
   | wsrep_flow_control_paused    | 0.000000                                |
   | wsrep_flow_control_paused_ns | 0                                       |
   | wsrep_flow_control_recv      | 0                                       |
   | wsrep_flow_control_sent      | 0                                       |
   | wsrep_gcomm_uuid             | d0460120-d932-11e8-8779-7fda4c3b845f    |
   | wsrep_incoming_addresses     | 192.168.100.18:3306,192.168.100.17:3306 |