Percona XtraDB Cluster 集群环境建立与验证指南

Percona XtraDB Cluster 是MySQL数据库的一种集群方案。并且与 MySQL Server 社区版本、Percona Server 和 MariaDB 兼容。
一、在Ubuntu上安装Percona XtraDB Cluster
实验环境：
    假设有3台计算机设备安装了ubuntu系统，将被用作3个节点：
    Node        Host        IP
    Node1       pxc1        172.16.24.209
    Node2       pxc2        172.16.24.208
    Node3       pxc3        172.16.24.207
前置条件：
    (1) 确保一下端口没被防火墙屏蔽或被其他进程占用：
    3306
    4444
    4567
    4568
    (2) 卸载 apparmor
    sudo apt-get remove apparmor
安装步骤：
    在每一台设备上执行下列命令：
    wget https://repo.percona.com/apt/percona-release_0.1-4.$(lsb_release -sc)_all.deb
    sudo dpkg -i percona-release_0.1-4.$(lsb_release -sc)_all.deb
    sudo apt update
    sudo apt install percona-xtradb-cluster-full-57
    passord:（设置root用户的密码）
    
    至此，percona-xtradb-cluster已经安装，mysql进程会自动开始运行.
    sudo service mysql stop
    
二、配置节点
1. 初始化集群
以第1台设备作为第1个集群节点。在 /etc/mysql/my.cnf 添加如下配置：
###############################################################
[mysqld]
wsrep_provider=/usr/lib/libgalera_smm.so
wsrep_cluster_name=pxc-cluster
wsrep_cluster_address=gcomm://
wsrep_node_name=pxc1
wsrep_node_address=172.16.24.209
wsrep_sst_method=xtrabackup-v2
wsrep_sst_auth=sstuser:passw0rd
pxc_strict_mode=ENFORCING
binlog_format=ROW
default_storage_engine=InnoDB
innodb_autoinc_lock_mode=2
log_error=/var/log/mysql/error.log
###############################################################
完成修改之后，执行：
sudo /etc/init.d/mysql bootstrap-pxc
数据库将以自举模式启动。至此，集群初始化工作已经完成。登录MySQL，查看初始化结果：
bn@u16:~$ mysql -uroot -p
Enter password: （输入root用户的密码）
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 15
Server version: 5.7.19-17-57-log Percona XtraDB Cluster (GPL), Release rel17, Revision c10027a, WSREP version 29.22, wsrep_29.22
Copyright (c) 2009-2017 Percona LLC and/or its affiliates
Copyright (c) 2000, 2017, 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> CREATE USER 'sstuser'@'localhost' IDENTIFIED BY 'passw0rd';
mysql> GRANT ALL PRIVILEGES ON *.* TO 'sstuser'@'localhost';
mysql> FLUSH PRIVILEGES;
mysql> quit
mysql> show status like 'wsrep%';
+----------------------------------+--------------------------------------+
| Variable_name                    | Value                                |
+----------------------------------+--------------------------------------+
| wsrep_local_state_uuid           | 0d718de1-a19c-11e7-81e3-127c64915155 |
| wsrep_protocol_version           | 7                                    |
| wsrep_last_committed             | 4                                    |
...
| wsrep_local_state_comment        | Synced                               |
...
| wsrep_cluster_conf_id            | 1                                    |
| wsrep_cluster_size               | 1                                    |
| wsrep_cluster_state_uuid         | 0d718de1-a19c-11e7-81e3-127c64915155 |
| wsrep_cluster_status             | Primary                              |
| wsrep_connected                  | ON                                   |
| wsrep_local_bf_aborts            | 0                                    |
| wsrep_local_index                | 0                                    |
| wsrep_provider_name              | Galera                               |
| wsrep_provider_vendor            | Codership Oy <info@codership.com>    |
| wsrep_provider_version           | 3.22(r8678538)                       |
| wsrep_ready                      | ON                                   |
+----------------------------------+--------------------------------------+
67 rows in set (0.00 sec)
2. 添加节点
添加第2台设备，修改其配置文件 /etc/mysql/my.cnf ，添加如下语句：
###############################################################
[mysqld]
wsrep_provider=/usr/lib/libgalera_smm.so
wsrep_cluster_name=pxc-cluster
wsrep_cluster_address=gcomm://172.16.24.209,172.16.24.208,172.16.24.207
wsrep_node_name=pxc2
wsrep_node_address=172.16.24.208
wsrep_sst_method=xtrabackup-v2
wsrep_sst_auth=sstuser:passw0rd
pxc_strict_mode=ENFORCING
binlog_format=ROW
default_storage_engine=InnoDB
innodb_autoinc_lock_mode=2
log_error=/var/log/mysql/error.log
###############################################################
退出重启即可。重启后也登录MySQL,执行“show status like 'wsrep%';”，查看添加结果。
添加第3台设备，修改其配置文件 /etc/mysql/my.cnf ，添加如下语句：
###############################################################
[mysqld]
wsrep_provider=/usr/lib/libgalera_smm.so
wsrep_cluster_name=pxc-cluster
wsrep_cluster_address=gcomm://172.16.24.209,172.16.24.208,172.16.24.207
wsrep_node_name=pxc3
wsrep_node_address=172.16.24.207
wsrep_sst_method=xtrabackup-v2
wsrep_sst_auth=sstuser:passw0rd
pxc_strict_mode=ENFORCING
binlog_format=ROW
default_storage_engine=InnoDB
innodb_autoinc_lock_mode=2
log_error=/var/log/mysql/error.log
###############################################################
退出重启即可。重启后也登录MySQL,执行“show status like 'wsrep%';”，查看添加结果。
三、验证写集复制功能(Write-Set Replication)
1. Create a new database on the second node:
mysql> CREATE DATABASE testDB1;
Query OK, 1 row affected (0.00 sec)
2. Create a table on the third node:
mysql> USE testDB1
Database changed
mysql> CREATE TABLE example (node_id INT PRIMARY KEY, node_name VARCHAR(30));
Query OK, 0 rows affected (0.01 sec)
3. Insert records on the first node:
mysql> INSERT INTO testDB1.example VALUES (1, 'percona1');
Query OK, 1 row affected (0.01 sec)
4. Retrieve rows from that table on the second node:
mysql> SELECT * FROM testDB1.example;
+---------+-----------+
| node_id | node_name |
+---------+-----------+
|       1 | percona1  |
+---------+-----------+
1 row in set (0.00 sec)
四、PXC集群开机关机顺序
    集群的第1个节点启动完成之后，才可以启动其他节点。。
    集群的第1个节点必须等待其他节点都关机完成之后才能关机。
参考文档：
Percona-XtraDB-Cluster-5.7.18-29.20.pdf