Mariadb galera Cluster安装：
操作系统：CentOS 7.4版本
集群数量：3个节点
主机信息： 192.168.153.142 node1 selinux=disabled firewalld关闭
192.168.153.143 node2 selinux=disabled firewalld关闭
192.168.153.144 node3 selinux=disabled firewalld关闭
搭建步骤
1.主机之间互相解析：三台节点都要执行
vim /etc/hosts
192.168.153.142 node1
192.168.153.143 node2
192.168.153.144 node3
2.安装软件包
第一种方法：（yum install -y MariaDB-server MariaDB-client galera）
配置yum安装源和配置mariadb galera安装源
yum源配置挂iso
设置mariadb的yum源并安装（所有节点都要）
修改yum源文件
vi /etc/yum.repos.d/mariadb.repo
[mariadb]
name = MariaDB
baseurl =
gpgkey=https://yum.mariadb.org/RPM-GPG-KEY-MariaDB
gpgcheck=1
enabled=0
安装galera软件时需要解决它的依赖包：boost-program-options.x86_64 （直接yum源安装即可）
第二种方法：（rpm包安装）三个节点都需要安装
从网上下载rpm包： galera-25.3.23-1.rhel7.el7.centos.x86_64.rpm
MariaDB-10.3.5-centos74-x86_64-client.rpm
MariaDB-10.3.5-centos74-x86_64-compat.rpm
MariaDB-10.3.5-centos74-x86_64-common.rpm
MariaDB-10.3.5-centos74-x86_64-server.rpm
rpm -ivh MariaDB-10.3.5-centos74-x86_64-compat.rpm --nodeps
rpm -ivh MariaDB-10.3.5-centos74-x86_64-common.rpm
rpm -ivh MariaDB-10.3.5-centos74-x86_64-client.rpm
yum install -y boost-program-options.x86_64 (解决安装galera的依赖包)
rpm -ivh galera-25.3.23-1.rhel7.el7.centos.x86_64.rpm
rpm -ivh MariaDB-10.3.5-centos74-x86_64-server.rpm
3.mariadb初始化 （三个节点都需要执行）
安装完成后会提示需要对mariadb进行初始化（设置密码）
systemctl start mariadb
mysql_secure_installation (按提示设置mysql密码)
systemctl stop mariadb
4.配置galera
主节点配置文件server.cnf
vim /etc/my.cnf.d/server.cnf
[galera]
wsrep_on=ON
wsrep_provider=/usr/lib64/galera/libgalera_smm.so
wsrep_cluster_address="gcomm://192.168.153.142,192.168.153.143,192.168.153.144"
wsrep_node_name= node1
wsrep_node_address=192.168.153.142
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
将此文件复制到mariadb-2、mariadb-3，注意要把 wsrep_node_name 和 wsrep_node_address 改成相应节点的 hostname 和 ip。
5.启动集群服务：
启动 MariaDB Galera Cluster 服务：
[root@node1 ~]# /bin/galera_new_cluster
剩余两节点启动方式为：
[root@node1 ~]# systemctl start mariadb
查看集群状态：（集群服务使用了4567和3306端口））
[root@node1 ~]# netstat -tulpn | grep -e 4567 -e 3306
tcp 0 0 0.0.0.0:4567 0.0.0.0: LISTEN 3557/mysqld
tcp6 0 0 :::3306 ::: LISTEN 3557/mysqld
6.验证集群状态：
在node1上执行：
[root@node1 ~]# mysql -uroot -p ##进入数据库
查看是否启用galera插件
连接mariadb,查看是否启用galera插件
MariaDB [(none)]> show status like "wsrep_ready";
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| wsrep_ready | ON |
+---------------+-------+
1 row in set (0.004 sec)
目前集群机器数
MariaDB [(none)]> show status like "wsrep_cluster_size";
+--------------------+-------+
| Variable_name | Value |
+--------------------+-------+
| wsrep_cluster_size | 3 |
+--------------------+-------+
1 row in set (0.001 sec)
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 | 1.000000 |
| wsrep_causal_reads | 14 |
| wsrep_cert_deps_distance | 1.200000 |
| wsrep_cert_index_size | 3 |
| wsrep_cert_interval | 0.000000 |
| wsrep_cluster_conf_id | 22 |
| wsrep_cluster_size | 3 | ##集群成员
| wsrep_cluster_state_uuid | b8ecf355-233a-11e8-825e-bb38179b0eb4 | ##UUID 集群唯一标记
| wsrep_cluster_status | Primary | ##主服务器
| wsrep_commit_oooe | 0.000000 |
| wsrep_commit_oool | 0.000000 |
| wsrep_commit_window | 1.000000 |
| wsrep_connected | ON | ##当前是否连接中
| 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 | 0eba3aff-2341-11e8-b45a-f277db2349d5 |
| wsrep_incoming_addresses | 192.168.153.142:3306,192.168.153.143:3306,192.168.153.144:3306 | ##连接中的数据库
| wsrep_last_committed | 9 | ##sql 提交记录
| wsrep_local_bf_aborts | 0 | ##从执行事务过程被本地中断
| wsrep_local_cached_downto | 5 |
| wsrep_local_cert_failures | 0 | ##本地失败事务
| wsrep_local_commits | 4 | ##本地执行的sql
| wsrep_local_index | 0 |
| wsrep_local_recv_queue | 0 |
| wsrep_local_recv_queue_avg | 0.057143 |
| wsrep_local_recv_queue_max | 2 |
| wsrep_local_recv_queue_min | 0 |
| wsrep_local_replays | 0 |
| wsrep_local_send_queue | 0 | ##本地发出的队列
| wsrep_local_send_queue_avg | 0.000000 | ##队列平均时间间隔
| wsrep_local_send_queue_max | 1 |
| wsrep_local_send_queue_min | 0 |
| wsrep_local_state | 4 |
| wsrep_local_state_comment | Synced |
| wsrep_local_state_uuid | b8ecf355-233a-11e8-825e-bb38179b0eb4 | ##集群ID
| wsrep_protocol_version | 8 |
| wsrep_provider_name | Galera |
| wsrep_provider_vendor | Codership Oy <info@codership.com> |
| wsrep_provider_version | 25.3.23(r3789) |
| wsrep_ready | ON | ##插件是否应用中
| wsrep_received | 35 | ##数据复制接收次数
| wsrep_received_bytes | 5050 |
| wsrep_repl_data_bytes | 1022 |
| wsrep_repl_keys | 14 |
| wsrep_repl_keys_bytes | 232 |
| wsrep_repl_other_bytes | 0 |
| wsrep_replicated | 5 | ##随着复制发出的次数
| wsrep_replicated_bytes | 1600 | ##数据复制发出的字节数
| wsrep_thread_count | 2 |
+------------------------------+----------------------------------------------------------------+
58 rows in set (0.003 sec)
查看连接的主机
MariaDB [(none)]> show status like "wsrep_incoming_addresses";
+--------------------------+----------------------------------------------------------------+
| Variable_name | Value |
+--------------------------+----------------------------------------------------------------+
| wsrep_incoming_addresses | 192.168.153.142:3306,192.168.153.143:3306,192.168.153.144:3306 |
+--------------------------+----------------------------------------------------------------+
1 row in set (0.002 sec)
7.测试集群mariad数据是否同步
MariaDB [(none)]> create database lizk;
Query OK, 1 row affected (0.010 sec)