下载与安装 MariaDB Galera Cluster
10.1之前的版本安装，输入以下命令进行安装：
sudo dnf install mariadb-galera-server
如果电脑上还没安装Mariadb Server，会顺便安装上，如果已经安装了，则会更新相关的包。
10.1之后的版本，Mariadb Server把群集功能打包在一起了，所以直接安装数据库，不用单独安装：
sudo dnf install mariadb-server
配置
基本步骤，使用--wsrep-new-cluster创建一个集群(只在第一个节点上使用），用--wsrep_cluster_address=gcomm://192.168.0.1加入节点。
由于文本使用的是Fedora，服务管理是systemd，所以需要修改mariadb.service，将参数加进去。
修改后的启动文件：
[Unit]
Description=MariaDB 10.1 database server
After=network.target
[Service]
Type=notify
User=mysql
Group=mysql
ExecStartPre=/usr/libexec/mysql-check-socket
# '%n' expands to 'Full unit name'; man systemd.unit
ExecStartPre=/usr/libexec/mysql-prepare-db-dir %n
# MYSQLD_OPTS here is for users to set in /etc/systemd/system/mariadb@.service.d/MY_SPECIAL.conf
# Note: we set --basedir to prevent probes that might trigger SELinux alarms,
# per bug #547485
ExecStart=/usr/libexec/mysqld --basedir=/usr $MYSQLD_OPTS $_WSREP_NEW_CLUSTER $_WSREP_CLUSTER_ADDRESS
ExecStartPost=/usr/libexec/mysql-check-upgrade
ExecStopPost=/usr/libexec/mysql-wait-stop
# Setting this to true can break replication and the Type=notify settings
# See also bind-address mysqld option.
PrivateNetwork=false
KillMode=process
KillSignal=SIGTERM
# Don't want to see an automated SIGKILL ever
SendSIGKILL=no
# Restart crashed server only, on-failure would also restart, for example, when
# my.cnf contains unknown option
Restart=on-abort
RestartSec=5s
UMask=007
# Give a reasonable amount of time for the server to start up/shut down
TimeoutSec=300
# Place temp files in a secure directory, not /tmp
PrivateTmp=true
[Install]
WantedBy=multi-user.target
第一个节点的环境设置：
systemctl show-environment
LANG=en_US.UTF-8
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin
_WSREP_CLUSTER_ADDRESS=--wsrep_cluster_address=gcomm://192.168.30.184
_WSREP_NEW_CLUSTER=--wsrep-new-cluster
第二个节点的环境配置
systemctl show-environment
LANG=en_US.UTF-8
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin
_WSREP_CLUSTER_ADDRESS=--wsrep_cluster_address=gcomm://192.168.30.184
测试
为测试方便，先将防火墙关闭，还有selinux。先启动第一个节点，再启动第二个节点。在其中一个节点上创建一个数据库，切换到另一个节点上就可以看到这个数据库。
通过数据命令可以查看集群的状态：
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 | 0 | | wsrep_cert_deps_distance | 1.000000 | | wsrep_cert_index_size | 2 | | wsrep_cert_interval | 0.000000 | | wsrep_cluster_conf_id | 189 | | wsrep_cluster_size | 2 | | wsrep_cluster_state_uuid | e5b100e2-7f7e-11e7-9266-de309a905227 | | wsrep_cluster_status | Primary | | wsrep_commit_oooe | 0.000000 | | wsrep_commit_oool | 0.000000 | | wsrep_commit_window | 1.000000 | | 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 | f023c418-7f81-11e7-bfbb-86741b99a879 | | wsrep_incoming_addresses | 192.168.30.184:3306,192.168.30.186:3306 | | wsrep_last_committed | 3 | | wsrep_local_bf_aborts | 0 | | wsrep_local_cached_downto | 1 | | wsrep_local_cert_failures | 0 | | wsrep_local_commits | 0 | | wsrep_local_index | 1 | | wsrep_local_recv_queue | 0 | | wsrep_local_recv_queue_avg | 0.125000 | | wsrep_local_recv_queue_max | 2 | | wsrep_local_recv_queue_min | 0 | | wsrep_local_replays | 0 | | wsrep_local_send_queue | 0 | | wsrep_local_send_queue_avg | 0.000000 | | 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 | e5b100e2-7f7e-11e7-9266-de309a905227 | | wsrep_protocol_version | 7 | | wsrep_provider_name | Galera | | wsrep_provider_vendor | Codership Oy <info@codership.com> | | wsrep_provider_version | 3.16(r5c765eb) | | wsrep_ready | ON | | wsrep_received | 8 | | wsrep_received_bytes | 2148 | | wsrep_repl_data_bytes | 0 | | wsrep_repl_keys | 0 | | wsrep_repl_keys_bytes | 0 | | wsrep_repl_other_bytes | 0 | | wsrep_replicated | 0 | | wsrep_replicated_bytes | 0 | | wsrep_thread_count | 2 | +------------------------------+-----------------------------------------+