如何搭建Percona XtraDB Cluster集群

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如何搭建 Percona XtraDB Cluster 集群

一、环境准备

主机 IP 主机名操作系统版本 PXC

192.168.244.146 node1 CentOS7.1 Percona-XtraDB-Cluster-56-5.6.30

192.168.244.147 node2 CentOS7.1 Percona-XtraDB-Cluster-56-5.6.30

192.168.244.148 node3 CentOS7.1 Percona-XtraDB-Cluster-56-5.6.30

关闭防火墙或者允许 3306, 4444, 4567 和 4568 四个端口的连接

关闭 SElinux

二、下载 PXC

安装 PXC yum 源

# yum install http://www.percona.com/downloads/percona-release/RedHat/0.1-3/percona-release-0.1-3.noarch.rpm

这样会在 /etc/yum.repos.d 下生成 percona-release.repo 文件

安装 PXC

# yum install Percona-XtraDB-Cluster-56

最终下载下来的版本是 Percona-XtraDB-Cluster-56-5.6.30

注意：三个节点上均要安装。

三、配置节点

配置节点一

修改 node1 的 /etc/my.cnf

[mysqld]

datadir=/var/lib/mysql
user=mysql

# Path to Galera library
wsrep_provider=/usr/lib64/galera3/libgalera_smm.so

# Cluster connection URL contains the IPs of node#1, node#2 and node#3
wsrep_cluster_address=gcomm://192.168.244.146,192.168.244.147,192.168.244.148

# 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

# This changes how InnoDB autoincrement locks are managed and is a requirement for Galera
innodb_autoinc_lock_mode=2

# Node #1 address
wsrep_node_address=192.168.244.146

# SST method
wsrep_sst_method=xtrabackup-v2

# Cluster name
wsrep_cluster_name=my_centos_cluster

# Authentication for SST method
wsrep_sst_auth="sstuser:s3cret"

启动 node1

# systemctl start mysql@bootstrap.service

注意：这个是 CentOS 7 下的启动方式，如果是 CentOS 6，则启动方式为 # /etc/init.d/mysql bootstrap-pxc

之所以采用 bootstrap 启动，其实是告诉数据库，这是第一个节点，不用进行数据的同步。

利用这种方式启动，相当于 wsrep_cluster_address 方式设置为 gcomm://。

此时，可登录客户端查看数据库的状态

mysql> show status like ‘wsrep%’;

主要关注以下参数的状态

+------------------------------+--------------------------------------+
| Variable_name                | Value                                |
+------------------------------+--------------------------------------+
| wsrep_local_state_uuid       | 1fbb69e3-32a3-11e6-a571-aeaa962bae0c |
 ...
| wsrep_local_state            | 4   
| wsrep_local_state_comment    | Synced                               |
 ...
| wsrep_cluster_size           | 1
 ...
| wsrep_cluster_status         | Primary                              |
| wsrep_connected              | ON                                   |
 ...
| wsrep_ready                  | ON                                   |

在上面的配置文件中，有个 wsrep_sst_auth 参数。该参数是用于其它节点加入到该集群中，利用 XtraBackup 执行 State Snapshot Transfer（类似于全量同步）的。

所以，接下来是授权

mysql> CREATE USER 'sstuser'@'localhost' IDENTIFIED BY 's3cret';
mysql> GRANT RELOAD, LOCK TABLES, REPLICATION CLIENT ON *.* TO 'sstuser'@'localhost';
mysql> FLUSH PRIVILEGES;

配置节点二

修改 node2 的 /etc/my.cnf

[mysqld]

datadir=/var/lib/mysql
user=mysql

# Path to Galera library
wsrep_provider=/usr/lib64/galera3/libgalera_smm.so

# Cluster connection URL contains the IPs of node#1, node#2 and node#3
wsrep_cluster_address=gcomm://192.168.244.146,192.168.244.147,192.168.244.148

# 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

# This changes how InnoDB autoincrement locks are managed and is a requirement for Galera
innodb_autoinc_lock_mode=2

# Node #2 address
wsrep_node_address=192.168.244.147

# SST method
wsrep_sst_method=xtrabackup-v2

# Cluster name
wsrep_cluster_name=my_centos_cluster

# Authentication for SST method
wsrep_sst_auth="sstuser:s3cret"

启动 node2

# systemctl start mysql

如果是 CentOS 6，则启动方式为 # /etc/init.d/mysql start

如果在启动的过程中出现问题，可查看 mysql 的错误日志，如果是 RPM 安装，默认是 /var/lib/mysql/ 主机名.err

启动完毕后，也可通过 mysql> show status like ‘wsrep%’; 命令查看集群的信息。

配置节点三

修改 node3 的 /etc/my.cnf

[mysqld]
datadir=/var/lib/mysql
user=mysql

# Path to Galera library
wsrep_provider=/usr/lib64/galera3/libgalera_smm.so

# Cluster connection URL contains the IPs of node#1, node#2 and node#3
wsrep_cluster_address=gcomm://192.168.244.146,192.168.244.147,192.168.244.148

# 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

# This changes how InnoDB autoincrement locks are managed and is a requirement for Galera
innodb_autoinc_lock_mode=2

# Node #3 address
wsrep_node_address=192.168.244.148

# SST method
wsrep_sst_method=xtrabackup-v2

# Cluster name
wsrep_cluster_name=my_centos_cluster

# Authentication for SST method
wsrep_sst_auth="sstuser:s3cret"

启动 node3

# systemctl start mysql

登录数据库，查看集群的状态

+------------------------------+--------------------------------------+
| Variable_name                | Value                                |
+------------------------------+--------------------------------------+
| wsrep_local_state_uuid       | 1fbb69e3-32a3-11e6-a571-aeaa962bae0c |
 ...
| wsrep_local_state            | 4   
| wsrep_local_state_comment    | Synced                               |
 ...
| wsrep_cluster_size           | 3
 ...
| wsrep_cluster_status         | Primary                              |
| wsrep_connected              | ON                                   |
 ...
| wsrep_ready                  | ON

通过 wsrep_cluster_size 可以看出集群有 3 个节点。

四、测试

下面来测试一把，在 node3 中创建一张表，并插入记录，看 node1 和 node2 中能否查询得到。

node3 中创建测试表并插入记录

root@node3 > create table test.test(id int,description varchar(10));
Query OK, 0 rows affected (0.18 sec)

root@node3 > insert into test.test values(1,'hello,pxc');
Query OK, 1 row affected (0.01 sec)

node1 和 node2 中查询

root@node1 > select * from test.test;
+------+-------------+
| id   | description |
+------+-------------+
|    1 | hello,pxc   |
+------+-------------+
1 row in set (0.00 sec)

root@node2 > select * from test.test;
+------+-------------+
| id   | description |
+------+-------------+
|    1 | hello,pxc   |
+------+-------------+
1 row in set (0.05 sec)

至此，Percona XtraDB Cluster 搭建完毕~

总结：

1. 刚开始启动 node2 的时候，启动失败，错误日志中报如下信息：

2016-06-15 20:06:09 4937 [ERROR] WSREP: failed to open gcomm backend connection: 110: failed to reach primary view: 110 (Connection timed out)
         at gcomm/src/pc.cpp:connect():162
2016-06-15 20:06:09 4937 [ERROR] WSREP: gcs/src/gcs_core.cpp:gcs_core_open():208: Failed to open backend connection: -110 (Connection timed out)
2016-06-15 20:06:09 4937 [ERROR] WSREP: gcs/src/gcs.cpp:gcs_open():1387: Failed to open channel 'my_centos_cluster' at 'gcomm://192.168.244.146,192.168.244.147,192.168.244.148': -110 (Connection timed out)
2016-06-15 20:06:09 4937 [ERROR] WSREP: gcs connect failed: Connection timed out
2016-06-15 20:06:09 4937 [ERROR] WSREP: wsrep::connect(gcomm://192.168.244.146,192.168.244.147,192.168.244.148) failed: 7
2016-06-15 20:06:09 4937 [ERROR] Aborting

2016-06-15 20:27:03 5870 [ERROR] WSREP: Failed to read 'ready <addr>' from: wsrep_sst_xtrabackup-v2 --role 'joiner' --address '192.168.244.147' --datadir '/var/lib/mysql/' --defaults-file '/etc/my.cnf' --defaults-group-suffix ''--parent'5870'''
        Read: '(null)'
2016-06-15 20:27:03 5870 [ERROR] WSREP: Process completed with error: wsrep_sst_xtrabackup-v2 --role 'joiner' --address '192.168.244.147' --datadir '/var/lib/mysql/' --defaults-file '/etc/my.cnf' --defaults-group-suffix ''--parent'5870''' : 2 (No such file or directory)
2016-06-15 20:27:03 5870 [ERROR] WSREP: Failed to prepare for 'xtrabackup-v2' SST. Unrecoverable.
2016-06-15 20:27:03 5870 [ERROR] Aborting