Configuring Percona XtraDB Cluster on Ubuntu¶

This tutorial describes how to install and configure three Percona XtraDB Cluster nodes on Ubuntu 12.04.2 LTS servers, using the packages from Percona repositories.

Node 1
Host name: pxc1
IP address: 192.168.70.61
Node 2
Host name: pxc2
IP address: 192.168.70.62
Node 3
Host name: pxc3
IP address: 192.168.70.63

Prerequisites¶

The procedure described in this tutorial requires he following:

All three nodes have Ubuntu 12.04.2 LTS installed.
Firewall on all nodes is configured to allow connecting to ports 3306, 4444, 4567 and 4568.
AppArmor profile for MySQL is disabled.

Step 1. Installing PXC¶

Install Percona XtraDB Cluster on all three nodes as described in Installing Percona XtraDB Cluster on Debian or Ubuntu.

Note

Debian/Ubuntu installation prompts for root password. For this tutorial, set it to Passw0rd. After the packages have been installed, mysqld will start automatically. Stop mysqld on all three nodes using /etc/init.d/mysql stop.

Step 2. Configuring the first node¶

Individual nodes should be configured to be able to bootstrap the cluster. For more information about bootstrapping the cluster, see Bootstrapping the First Node.

Make sure that the configuration file /etc/mysql/my.cnf for the first node (pxc1) contains the following:

[mysqld]

datadir=/var/lib/mysql
user=mysql

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

# Cluster connection URL contains the IPs of node#1, node#2 and node#3
wsrep_cluster_address=gcomm://192.168.70.61,192.168.70.62,192.168.70.63

# In order for Galera to work correctly, the binary log format should be ROW
binlog_format=ROW

# MyISAM storage engine has only experimental support
default_storage_engine=InnoDB

# This InnoDB autoincrement locking mode is a requirement for Galera
innodb_autoinc_lock_mode=2

# Node #1 address
wsrep_node_address=192.168.70.61

# SST method
wsrep_sst_method=xtrabackup-v2

# Cluster name
wsrep_cluster_name=my_ubuntu_cluster

# Authentication for SST method
wsrep_sst_auth="sstuser:s3cretPass"

Start the first node with the following command:

[root@pxc1 ~]# /etc/init.d/mysql bootstrap-pxc

This command will start the first node and bootstrap the cluster.

After the first node has been started, cluster status can be checked with the following command:

mysql> show status like 'wsrep%';

This output shows that the cluster has been successfully bootstrapped.

+----------------------------+--------------------------------------+
| Variable_name              | Value                                |
+----------------------------+--------------------------------------+
| wsrep_local_state_uuid     | b598af3e-ace3-11e2-0800-3e90eb9cd5d3 |
...
| wsrep_local_state          | 4                                    |
| wsrep_local_state_comment  | Synced                               |
...
| wsrep_cluster_size         | 1                                    |
| wsrep_cluster_status       | Primary                              |
| wsrep_connected            | ON                                   |
...
| wsrep_ready                | ON                                   |
+----------------------------+--------------------------------------+
40 rows in set (0.01 sec)

To perform State Snapshot Transfer using XtraBackup, set up a new user with proper privileges:

mysql@pxc1> CREATE USER 'sstuser'@'localhost' IDENTIFIED BY 's3cretPass';
mysql@pxc1> GRANT PROCESS, RELOAD, LOCK TABLES, REPLICATION CLIENT ON *.* TO 'sstuser'@'localhost';
mysql@pxc1> FLUSH PRIVILEGES;

Note

MySQL root account can also be used for performing SST, but it is more secure to use a different (non-root) user for this.

Step 3. Configuring the second node¶

Make sure that the configuration file /etc/mysql/my.cnf on the second node (pxc2) contains the following:

[mysqld]

datadir=/var/lib/mysql
user=mysql

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

# Cluster connection URL contains IPs of node#1, node#2 and node#3
wsrep_cluster_address=gcomm://192.168.70.61,192.168.70.62,192.168.70.63

# 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 InnoDB autoincrement locking mode is a requirement for Galera
innodb_autoinc_lock_mode=2

# Node #2 address
wsrep_node_address=192.168.70.62

# Cluster name
wsrep_cluster_name=my_ubuntu_cluster

# SST method
wsrep_sst_method=xtrabackup-v2

# Authentication for SST method
wsrep_sst_auth="sstuser:s3cretPass"

Start the second node with the following command:

[root@pxc2 ~]# /etc/init.d/mysql start

After the server has been started, it should receive SST automatically. Cluster status can now be checked on both nodes. The following is an example of status from the second node (pxc2):

mysql> show status like 'wsrep%';

This output shows that the new node has been successfully added to the cluster.

+----------------------------+--------------------------------------+
| Variable_name              | Value                                |
+----------------------------+--------------------------------------+
| wsrep_local_state_uuid     | b598af3e-ace3-11e2-0800-3e90eb9cd5d3 |
...
| wsrep_local_state          | 4                                    |
| wsrep_local_state_comment  | Synced                               |
...
| wsrep_cluster_size         | 2                                    |
| wsrep_cluster_status       | Primary                              |
| wsrep_connected            | ON                                   |
...
| wsrep_ready                | ON                                   |
+----------------------------+--------------------------------------+
40 rows in set (0.01 sec)

Step 4. Configuring the third node¶

Make sure that the MySQL configuration file /etc/mysql/my.cnf on the third node (pxc3) contains the following:

[mysqld]

datadir=/var/lib/mysql
user=mysql

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

# Cluster connection URL contains IPs of node#1, node#2 and node#3
wsrep_cluster_address=gcomm://192.168.70.61,192.168.70.62,192.168.70.63

# 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 InnoDB autoincrement locking mode is a requirement for Galera
innodb_autoinc_lock_mode=2

# Node #3 address
wsrep_node_address=192.168.70.63

# Cluster name
wsrep_cluster_name=my_ubuntu_cluster

# SST method
wsrep_sst_method=xtrabackup-v2

#Authentication for SST method
wsrep_sst_auth="sstuser:s3cretPass"

Start the third node with the following command:

[root@pxc3 ~]# /etc/init.d/mysql start

After the server has been started, it should receive SST automatically. Cluster status can be checked on all nodes. The following is an example of status from the third node (pxc3):

mysql> show status like 'wsrep%';

This output confirms that the third node has joined the cluster.

+----------------------------+--------------------------------------+
| Variable_name              | Value                                |
+----------------------------+--------------------------------------+
| wsrep_local_state_uuid     | b598af3e-ace3-11e2-0800-3e90eb9cd5d3 |
...
| wsrep_local_state          | 4                                    |
| wsrep_local_state_comment  | Synced                               |
...
| wsrep_cluster_size         | 3                                    |
| wsrep_cluster_status       | Primary                              |
| wsrep_connected            | ON                                   |
...
| wsrep_ready                | ON                                   |
+----------------------------+--------------------------------------+
40 rows in set (0.01 sec)

This output confirms that the third node has joined the cluster.

Testing replication¶

To test replication, lets create a new database on the second node, create a table for that database on the third node, and add some records to the table on the first node.

Create a new database on the second node:

mysql@pxc2> CREATE DATABASE percona;

The following output confirms that a new database has been created:

Query OK, 1 row affected (0.01 sec)

Switch to a newly created database:

mysql@percona3> USE percona;

The following output confirms that a database has been changed:

Database changed

Create a table on the third node:

mysql@pxc3> CREATE TABLE example (node_id INT PRIMARY KEY, node_name VARCHAR(30));

The following output confirms that a table has been created:

Query OK, 0 rows affected (0.05 sec)

Insert records on the first node:

mysql@percona1> INSERT INTO percona.example VALUES (1, 'percona1');

The following output confirms that the records have been inserted:

Query OK, 1 row affected (0.02 sec)

Retrieve all the rows from that table on the second node:

mysql@percona2> SELECT * FROM percona.example;

The following output confirms that all the rows have been retrieved:

+---------+-----------+
| node_id | node_name |
+---------+-----------+
|       1 | percona1  |
+---------+-----------+
1 row in set (0.00 sec)

This simple procedure should ensure that all nodes in the cluster are synchronized and working as intended.