PXC（PerconaXtraDBCluster）集群安装

作者在2014Oracle数据库嘉年华中有幸听到了关于去哪网的MySQL数据库基于PXC的高可用架构设计主题。 MySQL和Oracle是完全不同的两种数据库，Oracle重于管理，而MySQL更重要的是架构设计。笔者对MySQL以及新技术也是充满了好奇，索性回来自己搭建一个测试环境

作者在2014Oracle数据库嘉年华中有幸听到了关于去哪网的MySQL数据库基于PXC的高可用架构设计主题。

MySQL和Oracle是完全不同的两种数据库，Oracle重于管理，而MySQL更重要的是架构设计。笔者对MySQL以及新技术也是充满了好奇，索性回来自己搭建一个测试环境。

操作系统：CentOS 6.6

软件版本：5.5.39-36.0-55 PerconaXtraDB Cluster (GPL)

节点信息：

安装PXC，这里使用的是Percona以及EPEL的官方repositories ：

http://www.percona.com/doc/percona-server/5.5/installation/yum_repo.html?id=repositories:yum

http://fedoraproject.org/wiki/EPEL

yum installhttp://www.percona.com/downloads/percona-release/redhat/0.1-3/percona-release-0.1-3.noarch.rpm
yum installhttp://mirrors.ustc.edu.cn/fedora/epel/6/i386/epel-release-6-8.noarch.rpm
yum -y install Percona-XtraDB-Cluster-serverPercona-XtraDB-Cluster-client Percona-Server-shared-compat percona-xtrabackup

每台机器开启PXC，之后添加SST账户：

DELETE FROM mysql.user WHERE user='';
GRANT RELOAD, LOCK TABLES, REPLICATION CLIENT ON *.* TO 'sstuser'@'localhost' IDENTIFIED BY 'sstuser';;
FLUSH PRIVILEGES;

每个节点关闭PXC。编辑第一个节点的PXC设置。

[mysqld]
server_id=1
wsrep_provider=/usr/lib64/libgalera_smm.so
wsrep_cluster_address="gcomm://192.168.0.200,192.168.0.201,192.168.0.202"
wsrep_sst_auth=sstuser:sstuser
wsrep_provider_options="gcache.size=4G"
wsrep_cluster_name=Percona
wsrep_sst_method=xtrabackup
wsrep_node_name=pxc1
wsrep_slave_threads=4
log_slave_updates
innodb_locks_unsafe_for_binlog=1
innodb_autoinc_lock_mode=2

开启第一个节点（如果集群关闭，每次拥有正确信息的节点使用此命令开启集群）

[root@pxc1 ~]# service mysql bootstrap-pxc
Bootstrapping PXC (Percona XtraDBCluster)Starting MySQL (Percona XtraDB Cluster)..[  OK  ]
 

编辑另外两个节点的my.cnf配置文件需要修改的内容：

server_id=2
wsrep_node_name=pxc2

将其他两个节点加入到集群中

service mysql start

至此，集群安装结束。

以下是配置过程中的报错信息以及解决方法：

现象：

开启PXC节点的时候遇到

Failed to read output of: 'ip addr show | grep -E '^[ ]*inet' | grep -m1global | awk '{ print $2 }' | sed -e 's/\/.*//''
........
141120 22:46:35 [ERROR] WSREP: Permission denied
141120 22:46:35 [ERROR] WSREP: failed to open gcomm backend connection: 13:error while trying to listen 'tcp://0.0.0.0:4567?socket.non_blocking=1', asioerror 'Permission denied': 13 (Permission denied)

原因：

由于开启了SELINUX。

解决方法：

编辑文件/etc/sysconfig/selinux

把SELINUX设为disabled

重启后就会忽略selinux，或者直接执行命令

setenforce 0

立即生效。

现象：

添加节点到集群中的时候遇到

last inactive check morethan PT1.5S ago (PT3.50529S), skipping check

卡在这里

原因：

iptables

解决方法：

关闭iptables

chkconfig iptables off

service iptables stop

[root@pxc1 ~]# mysql

Welcome to the MySQL monitor.  Commands end with ; or \g.

Your MySQL connection id is 7

Server version: 5.5.39-36.0-55 Percona XtraDB Cluster (GPL), Release rel36.0, Revision 824, WSREP version 25.11, wsrep_25.11.r4023


Copyright (c) 2009-2014 Percona LLC and/or its affiliates

Copyright (c) 2000, 2014, 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 global status like 'wsrep_cluster_size';

+--------------------+-------+

| Variable_name      | Value |

+--------------------+-------+

| wsrep_cluster_size | 2     |

+--------------------+-------+

1 row in set (0.00 sec)


mysql> show global status like 'wsrep_cluster_size';

+--------------------+-------+

| Variable_name      | Value |

+--------------------+-------+

| wsrep_cluster_size | 3     |

+--------------------+-------+

1 row in set (0.00 sec)


mysql> create database dexdb ;

Query OK, 1 row affected (0.01 sec)


mysql> use dexdb

Database changed

mysql> create table dextb (id int ,name char(10))  engine=innodb ;

Query OK, 0 rows affected (0.03 sec)


mysql> insert into dextb values (1,'22') ;

Query OK, 1 row affected (0.01 sec)


mysql> insert into dextb values (1,'22') ;

Query OK, 1 row affected (0.00 sec)


mysql> commit ;

Query OK, 0 rows affected (0.00 sec)


mysql> select * from dextb ;

+------+------+

| id   | name |

+------+------+

|    1 | 22   |

|    1 | 22   |

+------+------+

2 rows in set (0.00 sec)





[root@pxc2 ~]# mysql

Welcome to the MySQL monitor.  Commands end with ; or \g.

Your MySQL connection id is 6

Server version: 5.5.39-36.0-55 Percona XtraDB Cluster (GPL), Release rel36.0, Revision 824, WSREP version 25.11, wsrep_25.11.r4023


Copyright (c) 2009-2014 Percona LLC and/or its affiliates

Copyright (c) 2000, 2014, 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 database ;

ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'database' at line 1

mysql> show databases ;

+--------------------+

| Database           |

+--------------------+

| information_schema |

| dexdb              |

| mysql              |

| performance_schema |

| test               |

+--------------------+

5 rows in set (0.01 sec)


mysql> use dexdb

Reading table information for completion of table and column names

You can turn off this feature to get a quicker startup with -A


Database changed

mysql> select * from dextb ;

+------+------+

| id   | name |

+------+------+

|    1 | 22   |

|    1 | 22   |

+------+------+

2 rows in set (0.00 sec)





[root@pxc3 ~]# service mysql start

MySQL (Percona XtraDB Cluster) is not running, but lock file (/var/lock/subsys/mysql) exists[FAILED]

Starting MySQL (Percona XtraDB Cluster).....[  OK  ]

[root@pxc3 ~]# mysql

Welcome to the MySQL monitor.  Commands end with ; or \g.

Your MySQL connection id is 6

Server version: 5.5.39-36.0-55 Percona XtraDB Cluster (GPL), Release rel36.0, Revision 824, WSREP version 25.11, wsrep_25.11.r4023


Copyright (c) 2009-2014 Percona LLC and/or its affiliates

Copyright (c) 2000, 2014, 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> use dexdb

Reading table information for completion of table and column names

You can turn off this feature to get a quicker startup with -A


Database changed

mysql> select * from dextb ;

+------+------+

| id   | name |

+------+------+

|    1 | 22   |

|    1 | 22   |

+------+------+

2 rows in set (0.00 sec)