刪除節點
直接停掉一個就可以了，比如停掉23之後
user_3306.sock>show status like 'wsrep_incoming_addresses';
+--------------------------+---------------------------------------+
| Variable_name | Value |
+--------------------------+---------------------------------------+
| wsrep_incoming_addresses | 192.168.56.22:3306,192.168.56.21:3306 |
+--------------------------+---------------------------------------+
1 row in set (0.00 sec)如果以後不用23，其它節點可以更改/etc/my.cnf中的參數
[root@pxc21 user_3306]# cat /etc/my.cnf | grep 23
wsrep_cluster_address=gcomm://192.168.56.21,192.168.56.22,192.168.56.23 #cluster 中的節點i去掉裏面的192.168.56.23，不需要重啓21和22
增加節點
要確認各機子中安裝了xtrabackup和socat
yum install
percona-xtrabackup-2.2.6-5042.el6.x86_64.rpm
yum install socat-1.7.2.4-1.el6.rf.x86_64.rpm
不然會報錯（當pxc中的一臺主機停止後重新與其它主機同步時也需要這兩個工具）
WSREP_SST: [ERROR] innobackupex not in path: /usr/sbin:/sbin:/usr/local/Percona-XtraDB-Cluster-5.5.39-rel36.0-25.11.828.Linux.x86_64//bin:/sbin:/usr/sbin:/bin:/usr/bin:/usr/local/Percona-XtraDB-Cluster-5.5.39-rel36.0-25.11.828.Linux.x86_64/bin (20150314
00:29:50.433)
WSREP_SST: [ERROR] socat not found in path: /usr/sbin:/sbin:/usr/local/Percona-XtraDB-Cluster-5.5.39-rel36.0-25.11.828.Linux.x86_64//bin:/sbin:/usr/sbin:/bin:/usr/bin:/usr/local/Percona-XtraDB-Cluster-5.5.39-rel36.0-25.11.828.Linux.x86_64/bin (20150314 00:36:42.763)
以上工具都有了後，直接更改新機的my.cnf，並啓動就可以了
[root@oel64 user_3306]# cat /etc/my.cnf | grep 22
wsrep_cluster_address=gcomm://192.168.56.21,192.168.56.22,192.168.56.24 #cluster 中的節點ip 會自動把21與22的數據複製過來，包括用戶
啓動後可以看到參數變了
user_3306.sock>show status like 'wsrep_incoming_addresses';
+--------------------------+----------------------------------------------------------+
| Variable_name | Value |
+--------------------------+----------------------------------------------------------+
| wsrep_incoming_addresses | 192.168.56.24:3306,192.168.56.22:3306,192.168.56.21:3306 |
+--------------------------+----------------------------------------------------------+
1 row in set (0.00 sec)登錄24檢查裏面的數據，可以看到21與22裏的數據在24也有了