（注意：
（1）文中红色字体部分不一定需要操作
（2）由于word文档编辑的原因，实际操作时部分命令需要手动输入！！直接复制粘贴会提示错误！！
）
一 搭建环境：
1 Ubuntu16.04版本（系统登录：root（199077））
2 mysql5.7（用户名root 密码199077）
二 安装环境：
首先，不论是在云服务器、物理机还是虚拟机上，至少需要3台主机（我们将这三台主机称为“Nodes”），对于每一个”Node”，硬件最低配置要求为：
- 1GHz单核CPU
- 512M的内存
- 100Mbps的网络连接
- 三台主机IP为：
- Node1: 192.168.93.135（主节点）
- Node2: 192.168.93.132（从节点1）
- Node3: 192.168.93.134（从节点2）
其次要禁用SElinux、防火墙配置、禁用AppArmor，
这些在Ubuntu14.04下都是不用配置的，所以就不详细说明配置步骤。但在16.04环境下需严格配置：
（1）禁用SELinux的mysqld
如果你启用了SELinux,它可能会阻止 mysqld从执行所需的操作。你必须禁用SELinux mysqld或允许配置它 mysqld上运行外部程序和开放的监听套接字端口外,非特权用户可以做的事情。
禁用SELinux mysql运行以下命令:
semanage permissive -a mysqld_t
（2）防火墙配置：我们需要在每个节点上设置其防火墙规则，使得各个节点能与集群通信。在每个节点上均执行如下命令：
iptables --append INPUT --protocol tcp
--source 192.168.93.135 --jump ACCEPT
iptables --apend INPUT --protocol tcp
--source 192.168.93.132 --jump ACCEPT
iptables --append INPUT --protocol tcp
--source 192.168.93.134 --jump ACCEPT
然后保存防火墙规则：
iptables-save
(3)禁用Ubuntu的apparmor：apparmor主要是Ubuntu系统中对mysql访问权限的控制，我们必须禁用AppArmor，以便配置mysql的mysqld能够运行外部程序。
禁用apparmor：
sudo ln -s /etc/apparmor.d/usr /etc/apparmor.d/disable/.sbin.mysqld
重启apparmor：
sudo service apparmor restart
注：如果不禁用，则在登录mysql时会出现如下错误：
apparmor="DENIED" operation="open" ........
对应解决方案：
第一种：依次执行如下命令：
apt install apparmor-utils
sudo aa-complain/etc/apparmor.d/usr.sbin.mysqld
service apparmor restart
第二种：直接修改apparmor配置文件
nano /etc/apparmor.d/usr.sbin.mysqld
在配置文件中增加”flags=(complain)”
/usr/sbin/mysqld flags=(complain) {
#include <abstractions/base>
#include <abstractions/nameservice>
#include <abstractions/user-tmp>
#include <abstractions/mysql>
........
三 开始安装
（1）安装对应依赖
apt-get install python-software-properties
apt-get install software-properties-common
（2）添加GunPG key
apt-key adv --keyserver keyserver.ubuntu.com --recv BC19DDBA
（3）配置Ubuntu下galera源
创建galera.list文件：
cd /etc/apt/sources.list.d
touch galera.list
nano -w galera.list
在galera.list中添加内容：
#deb http://releases.galeracluster.com/mysql-wsrep-5.7/ubuntu xenial main
#deb http://releases.galeracluster.com/galera-3/ubuntu xenial main
deb http://releases.galeracluster.com/ubuntu xenial main
如果不清楚自己的Ubuntu详细信息，可通过命令lsb_release -a来查看。
（4）继续配置源
cd /etc/apt/preferences.d
touch galera.pref
nano -w /etc/apt/preferences.d/galera.pref
在galera.pref文件中添加内容：
Package: *
Pin: origin releases.galeracluster.com
Pin-Priority: 1001
（5）接下来更新一下：apt-get update
(6) 一旦在所有三个服务器上更新了存储库，我们就可以在三台服务器上运行以下命令安装MySQL5.7的修补程序与Galera
apt-get install galera-3 galera-arbitrator-3 mysql-wsrep-5.7
（7）安装完成之后，在每一个节点上启动Mysql：
Service mysql start
（8）验证节点之间是否能互相ping通：
主节点135上：
Ping 192.168.93.132
Ping 192.168.93.134
从节点132上：
Ping 192.168.93.135
Ping 192.168.93.134
从节点134上：
Ping 192.168.93.135
Ping 192.168.93.132
能ping同则表示三节点之间能互相通信。
（9）分别在三个节点上修改mysql的配置文件/etc/mysql/my.cnf
主节点135上：
# Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 2 of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
#
# The MySQL database server configuration file.
#
# You can copy this to one of:
# - "/etc/mysql/my.cnf" to set global options,
# - "~/.my.cnf" to set user-specific options.
#
# One can use all long options that the program supports.
# Run program with --help to get a list of available options and with
# --print-defaults to see which it would actually understand and use.
#
# For explanations see
# http://dev.mysql.com/doc/mysql/en/server-system-variables.html
#
# * IMPORTANT: Additional settings that can override those from this file!
# The files must end with '.cnf', otherwise they'll be ignored.
#
!includedir /etc/mysql/conf.d/
!includedir /etc/mysql/mysql.conf.d/
[mysqld]
binlog_format=ROW
default-storage-engine=innodb
innodb_autoinc_lock_mode=2
wsrep_provider=/usr/lib/libgalera_smm.so
wsrep_provider_options="gcache.size=300M; gcache.page_size=1G"
wsrep_cluster_name="galeracluster1"
wsrep_cluster_address="gcomm://"
wsrep_sst_method=rsync
wsrep_sst_auth=wsrep:199077
wsrep_node_address="192.168.93.135"
wsrep_node_name=node135
bind-address=0.0.0.0
从节点132上：
# Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 2 of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
#
# The MySQL database server configuration file.
#
# You can copy this to one of:
# - "/etc/mysql/my.cnf" to set global options,
# - "~/.my.cnf" to set user-specific options.
#
# One can use all long options that the program supports.
# Run program with --help to get a list of available options and with
# --print-defaults to see which it would actually understand and use.
#
# For explanations see
# http://dev.mysql.com/doc/mysql/en/server-system-variables.html
#
# * IMPORTANT: Additional settings that can override those from this file!
# The files must end with '.cnf', otherwise they'll be ignored.
#
!includedir /etc/mysql/conf.d/
!includedir /etc/mysql/mysql.conf.d/
[mysqld]
binlog_format=ROW
default-storage-engine=innodb
innodb_autoinc_lock_mode=2
wsrep_provider=/usr/lib/libgalera_smm.so
wsrep_provider_options="gcache.size=300M; gcache.page_size=1G"
wsrep_cluster_name="galeracluster1"
wsrep_cluster_address="gcomm://192.168.93.135"
wsrep_sst_method=rsync
wsrep_sst_auth=wsrep:199077
wsrep_node_address="192.168.93.132"
wsrep_node_name=node132
bind-address=0.0.0.0
从节点134上：
# Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 2 of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
#
# The MySQL database server configuration file.
#
# You can copy this to one of:
# - "/etc/mysql/my.cnf" to set global options,
# - "~/.my.cnf" to set user-specific options.
#
# One can use all long options that the program supports.
# Run program with --help to get a list of available options and with
# --print-defaults to see which it would actually understand and use.
#
# For explanations see
#
# * IMPORTANT: Additional settings that can override those from this file!
# The files must end with '.cnf', otherwise they'll be ignored.
#
!includedir /etc/mysql/conf.d/
!includedir /etc/mysql/mysql.conf.d/
[mysqld]
binlog_format=ROW
default-storage-engine=innodb
innodb_autoinc_lock_mode=2
wsrep_provider=/usr/lib/libgalera_smm.so
wsrep_provider_options="gcache.size=300M; gcache.page_size=1G"
wsrep_cluster_name="galeracluster1"
wsrep_cluster_address="gcomm://192.168.93.135"
wsrep_sst_method=rsync
wsrep_sst_auth=wsrep:199077
wsrep_node_address="192.168.93.134"
wsrep_node_name=node134
bind-address=0.0.0.0
（10）
在每个节点上重启mysql：
Service mysql restart
(11) 试着在任意一个节点上登录其余两个节点，如果都能彼此登录，则表明三台服务器上的mysql彼此监听成功。
如在135上登录132，134
mysql -h 192.168.93.132 -u root -p
mysql -h 192.168.93.134 -u root -p
如果彼此登录不成功，则需要在每个节点上创建用户以实现mysql的远程登录。
。创建用户时，需要对应每个节点的mysql的配置文件/etc/mysql/my.cnf中的“wsrep_sst_auth=wsrep:199077”项，该项用来设置服务器之间mysql彼此访问的用户名和密码，其中wsrep为用户名，199077为密码。
具体创建命令如下：
每个节点数据库远程访问的创建
create user 'wsrep'@'%' identified by '199077';
create user 'root'@'%' identified by '199077';#这一句不是很清楚是否可以去掉
GRANT ALL PRIVILEGES ON *.* TO 'wsrep'@'%' WITH GRANT OPTION;
FLUSH PRIVILEGES;
创建完后重启各个节点的mysql,再试着在每个节点上登录其他节点是否成功。
如在从节点132上登录135、134的mysql
mysql -h 192.168.93.135 -u root -p #成功
mysql -h 192.168.93.134 -u root -p #成功
mysql -h 192.168.93.135 -u wsrep -p #成功
mysql -h 192.168.93.134 -u wsrep -p #成功
主节点135和从节点134也进行同样操作，如果均能登录，则设置成功！
（12）接下来，Ubuntu有一个特别的用户叫debian-sys-maint会来维持Mysql的运行任务，由于数据库的复制，这个维护的运行只会在第一个节点（即主节点）成功进行，在其他节点上则会失败，所以要将启动节点（即主节点）上的/etc/mysql/debian.cnf文件拷贝到其他节点上。
即在主节点135上执行如下命令：
scp /etc/mysql/debian.cnf root@192.168.93.132:/etc/mysql/
scp /etc/mysql/debian.cnf root@192.168.93.134:/etc/mysql/
执行过程中可能会失败，这个问题是因为在主节点的/etc/mysql/my.cnf文件中有一行要改为：
PermitRootLogin yes
这样就会成功了！当以上步骤都完成了之后，可以准备开始启动集群了！
注：步骤（12）我在实际中未操作过，但集群也成功了，Debian 对mysql集群的日常维护可能有一定影响，读者可自行研究。
四 启动集群
在主节点上将mysql服务先停掉然后重启，注意一定要在前面提到的wsrep_cluster_address="gcomm://"的节点上执行最开始的启动程序：
service mysql stop
service mysql start --wsrep-new-cluster
在其他节点上执行：service mysql restart
五 验证是否成功
查看数据表
登录主节点135：
mysql -u root -p
Enter password:
mysql> SHOW STATUS LIKE 'wsrep%';
重点关注的是下面这几行：
wsrep_ready | ON
如果状态是 ON，那么就要看：
wsrep_cluster_size | 3
如果是3，那么是成功的，否则是不成功的！
六 数据库复制测试
在主节点135上创建一个表：
CREATE database test;
立刻到节点132和134上使用 show databases; 查看是否也有了test这个数据库，如果有则成功！
七 集群的状态监控相关参数
（1）wsrep_cluster_state_uuid显示了cluster的state UUID,由此可看出该节点是否还是集群的一员；
SHOW GLOBAL STATUS LIKE 'wsrep_cluster_state_uuid'
（2）wsrep_cluster_conf_id显示了整个集群的变化次数。所有节点都应相同，否则说明某个节点与集群断开了；
（3）wsrep_cluster_status显示集群里节点的主状态。标准返回primary。如返回non-Primary或其他值说明是多个节点改变导致的节点丢失或者脑裂。如果所有节点都返回不是Primary，则要重设quorum。具体参见http://galeracluster.com/documentation-webpages/quorumreset.html如果返回都正常，说明复制机制在每个节点都能正常工作；
show global status like 'wsrep_cluster_status';
+----------------------+---------+
| Variable_name | Value |
+----------------------+---------+
| wsrep_cluster_status | Primary |
+----------------------+---------+
八 重启集群
偶尔，您可能不得不重新启动整个Galera集群。例如，在停电的情况下，每个节点都被关闭，并且根本没有mysqld进程，这可能会发生。
要重新启动整个Galera集群，请完成以下步骤：
九 配置过程中可能遇到的错误：
（1）Failed to restart mysql.service: Unit mysql.service is masked.
systemctl unmask mysql.service
service mysql start
（2）Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock'
解决途径：http://blog.csdn.net/luoxia0805/article/details/30265479
（3）