注意：不要创建偶数个数的集群，这会导致脑裂

1、安装PXC

先决条件

1. 需要主机root权限

2. 开放所需端口
   
   

   ~]# firewall-cmd --add-port=3306/tcp --permanent
   ~]# firewall-cmd --add-port=4444/tcp --permanent
   ~]# firewall-cmd --add-port=4567/tcp --permanent
   ~]# firewall-cmd --add-port=4568/tcp --permanent
   ~]# firewall-cmd --reload

   
   
3. 关闭SELinux

4. 安装必要软件

   ~]# yum install -y openssl socat  \
   procps-ng chkconfig procps-ng coreutils shadow-utils \
   grep libaio libev libcurl perl-DBD-MySQL perl-Digest-MD5 \
   libgcc libstdc++ libgcrypt libgpg-error zlib glibc openssl-libs

下载安装

1. https://www.percona.com/doc/percona-xtradb-cluster/LATEST/install/yum.html#yum

2. 本例下载后安装
   在三个节点上分别安装。

   [root@db1 pxc]# # yum install percona-xtradb-cluster-server-8.0.19-10.1.el7.x86_64.rpm \
   percona-xtradb-cluster-shared-8.0.19-10.1.el7.x86_64.rpm \
   percona-xtrabackup-24-2.4.12-1.el7.x86_64.rpm  \
   percona-xtradb-cluster-client-8.0.19-10.1.el7.x86_64.rpm  \
   percona-xtradb-cluster-shared-compat-8.0.19-10.1.el7.x86_64.rpm \
   qpress-1.1-9.2.x86_64.rpm

   
   

3. 首先启动第一个节点

   [root@db1 tmp]# systemctl start mysql
   [root@db1 tmp]# grep 'temporary password' /var/log/mysqld.log
   2020-07-02T16:35:09.693714Z 5 [Note] [MY-010454] [Server] A temporary password is generated for root@localhost: fr6H(XEP%i*i
   [root@db1 tmp]# mysql -u root -p
   Enter password: 
   Welcome to the MySQL monitor.  Commands end with ; or \g.
   Your MySQL connection id is 18
   Server version: 8.0.19-10
   
   Copyright (c) 2009-2020 Percona LLC and/or its affiliates
   Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
   
   Oracle is a registered trademark of Oracle Corporation and/or its
   affiliates. Other names may be trademarks of their respective
   owners.
   
   Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
   
   mysql> alter user 'root'@'localhost' identified by 'fr6H(XEP%i*i';
   Query OK, 0 rows affected (0.01 sec)
   
   mysql> flush privileges;
   Query OK, 0 rows affected (0.01 sec)
   
   mysql> 
   
   
   ######################################
   # 然后关闭该节点数据库!!!!!!
   ######################################
   [root@db1 tmp]# systemctl stop mysql

4. 配置Write-Set复制

   [root@db1 ~]# vim /etc/percona-xtradb-cluster.conf.d/wsrep.cnf
   [mysqld]
   # Path to Galera library
   wsrep_provider=/usr/lib64/libgalera_smm.so
    
   # Cluster connection URL contains IPs of nodes
   #If no IP is found, this implies that a new cluster needs to be created,
   #in order to do that you need to bootstrap this node
   wsrep_cluster_address=gcomm://192.168.56.104,192.168.56.105,192.168.56.106
    
   # In order for Galera to work correctly binlog format should be ROW
   binlog_format=ROW  
    
   # MyISAM storage engine has only experimental support
   default_storage_engine=InnoDB   
    
   # Slave thread to use
   wsrep_slave_threads= 8   
    
   wsrep_log_conflicts   
    
   # This changes how InnoDB autoincrement locks are managed and is a requirement for Galera
   innodb_autoinc_lock_mode=2   
    
   # Cluster name
   wsrep_cluster_name=pxc-cluster
    
   #If wsrep_node_name is not specified,  then system hostname will be used
   wsrep_node_name=db1
   # Node IP address
   wsrep_node_address=192.168.56.104
    
   #pxc_strict_mode allowed values: DISABLED,PERMISSIVE,ENFORCING,MASTER
   pxc_strict_mode=ENFORCING
    
   # SST method
   wsrep_sst_method=xtrabackup-v2 
   #Authentication for SST method
   # wsrep_sst_auth="sstuser:s3cp4tretPass"    # pxc 8.0 不需要此配置
    
   #############################################################
   #  如果配置如下ssl，请确保所有节点 datadir下具有相同的 *pem
   #############################################################
   wsrep_provider_options="socket.ssl_key=server-key.pem;socket.ssl_cert=server-cert.pem;socket.ssl_ca=ca.pem"
   
   [sst]
   encrypt=4
   ssl-key=server-key.pem
   ssl-ca=ca.pem
   ssl-cert=server-cert.pem
   ############################################################
   
   
   
    
   [root@db2 ~]# vim /etc/percona-xtradb-cluster.conf.d/wsrep.cnf
   #……
   #If wsrep_node_name is not specified,  then system hostname will be used
   wsrep_node_name=db2
   # Node IP address
   wsrep_node_address=192.168.56.105
   #……
    
    
   [root@db3 ~]# vim /etc/percona-xtradb-cluster.conf.d/wsrep.cnf
   #……
   #If wsrep_node_name is not specified,  then system hostname will be used
   wsrep_node_name=db3
   # Node IP address
   wsrep_node_address=192.168.56.106
   #……
   
   
   
   PS: 将该配置文件!include到/etc/my.cnf
   ######## wsrep ###############
   !include /etc/percona-xtradb-cluster.conf.d/wsrep.cnf

5. 启动第一个节点
   
   

   [root@db1 ~]# systemctl start mysql@bootstrap.service  
               # 当有其他节点正常加入进集群之后，可以关闭该节点，以正常方式再次启动
    
   [root@db1 tmp]# mysql -u root -h 127.0.0.1 -P 3306 -p
   Enter password: 
   Welcome to the MySQL monitor.  Commands end with ; or \g.
   Your MySQL connection id is 18
   Server version: 8.0.19-10 Percona XtraDB Cluster (GPL), Release rel10, Revision 727f180, WSREP version 26.4.3
   
   Copyright (c) 2009-2020 Percona LLC and/or its affiliates
   Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
   
   Oracle is a registered trademark of Oracle Corporation and/or its
   affiliates. Other names may be trademarks of their respective
   owners.
   
   Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
   
   mysql> show status like 'wsrep%';

   创建sst用户，【 pxc 8.0中不需要此步骤 】

   mysql> CREATE USER 'sstuser'@'localhost' IDENTIFIED BY 's3cp4tretPass';
   Query OK, 0 rows affected (0.01 sec)
    
   mysql> GRANT RELOAD, LOCK TABLES, PROCESS, REPLICATION CLIENT ON *.* TO  'sstuser'@'localhost';
   Query OK, 0 rows affected (0.01 sec)
    
   mysql> flush privileges;
   Query OK, 0 rows affected (0.00 sec)

6. 添加其他节点到集群
   
   配置好的节点启动之后会自动加入集群。
   
   

   [root@db2 ~]# systemctl start mysql
              # 这里有个蹩脚的问题， 如果要启动，datadir下需要为空，但是ssl pem文件需要用于传输（ssh pem文件位于datadir）
               # 因此，第一次启动失败，然后从节点1传送pem文件到datadir，再次启动即可成功。
    
   [root@db2 tmp]# mysql -u root -p
   Enter password: 
   Welcome to the MySQL monitor.  Commands end with ; or \g.
   Your MySQL connection id is 19
   Server version: 8.0.19-10 Percona XtraDB Cluster (GPL), Release rel10, Revision 727f180, WSREP version 26.4.3
   
   Copyright (c) 2009-2020 Percona LLC and/or its affiliates
   Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
   
   Oracle is a registered trademark of Oracle Corporation and/or its
   affiliates. Other names may be trademarks of their respective
   owners.
   
   Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
   
   mysql> show status like 'wsrep%';

   [root@db3 ~]# systemctl start mysql
              # 这里有个蹩脚的问题， 如果要启动，datadir下需要为空，但是ssl pem文件需要用于传输（ssh pem文件位于datadir）
               # 因此，第一次启动失败，然后从节点1传送pem文件到datadir，再次启动即可成功。
    
    
   [root@db3 tmp]# mysql -u root -p
   Enter password: 
   Welcome to the MySQL monitor.  Commands end with ; or \g.
   Your MySQL connection id is 19
   Server version: 8.0.19-10 Percona XtraDB Cluster (GPL), Release rel10, Revision 727f180, WSREP version 26.4.3
   
   Copyright (c) 2009-2020 Percona LLC and/or its affiliates
   Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
   
   Oracle is a registered trademark of Oracle Corporation and/or its
   affiliates. Other names may be trademarks of their respective
   owners.
   
   Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
   
   mysql> show status like 'wsrep%';

   
   

7. 关闭并正常启动节点1

   [root@db1 tmp]# systemctl stop mysql@bootstrap.service
   [root@db1 tmp]# 
   [root@db1 tmp]# systemctl start mysql

8. 验证节点间复制