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/[email protected]/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 <[email protected]>       |
| 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                                       |
+------------------------------+-----------------------------------------+