Setup MariaDB Galera Cluster 10.0 On CentOS7

This guide looks into how to setup MariaDB Galera Cluster on CentOS7. MariaDB Galera Cluster is a synchronous multi-master cluster for MariaDB. It is is an easy-to-use, high-availability solution, which provides high system uptime, no data loss and scalability for future growth. It only supports the XtraDB/InnoDB storage engines

Features:
Synchronous replication
Active-active multi-master topology
Read and write to any cluster node
Automatic membership control, failed nodes drop from the cluster
Automatic node joining
True parallel replication, on row level
Direct client connections, native MySQL look & feel

Benefits:
The above features yield several benefits for a DBMS clustering solution, including:
No slave lag
No lost transactions
Both read and write scalability
Smaller client latencies

For this setup, we have 2 nodes.(ie 192.168.1.11,192.168.1.12.) MariaDB will first setup in (.11) and start in bootstrap mode. After (.11) has started, (.12) will setup next. Once the MariaDB service on (.12) started, Galera process will sync database data and transactions from (.11) to (.12), and after in sync, MariaDB in (.12) will turn on. Both servers will be multi masters and in sync constantly.

To begin with the setup, for simplicity, we will switch off selinux and firewall.

[root@centos7-11 ~]#systemctl stop firewalld
[root@centos7-11 ~]#systemctl disable firewalld
[root@centos7-11 ~]#vi /etc/selinux/config

disabled

[root@centos7-11 ~]#reboot

We will add a repository from MariaDB.

[root@centos7-11 ~]# vi /etc/yum.repos.d/mariadb.repo

[mariadb]
name = MariaDB
baseurl = http://yum.mariadb.org/10.0/centos6-amd64
gpgkey=https://yum.mariadb.org/RPM-GPG-KEY-MariaDB
gpgcheck=1

Install the package using YUM.

[root@centos7-11 ~]# yum clean all
[root@centos7-11 ~]# yum install MariaDB-Galera-server

Setup MariaDB.(At this point,the service is still call mysql.)

[root@centos7-11 ~]# service mysql start
[root@centos7-11 ~]# mysql_secure_installation

Stop the mysql service to adjust the MariaDB config file.

[root@centos7-11 ~]# service mysql stop
[root@centos7-11 ~]# vi /etc/my.cnf

!includedir /etc/my.cnf.d

Add replication parameters to server.cnf

[root@centos7-11 ~]# vi /etc/my.cnf.d/server.cnf 

[galera]
# Mandatory settings
wsrep_provider=/usr/lib64/galera/libgalera_smm.so
wsrep_cluster_address=gcomm://
binlog_format=row
default_storage_engine=InnoDB
innodb_autoinc_lock_mode=2
bind-address=192.168.1.11
#
# Optional setting
#wsrep_slave_threads=1
#innodb_flush_log_at_trx_commit=0

We can start the MariaDB on first node.(.11)

[root@centos7-11 ~]# service mysql start

By now, this node has setup to be the first master database. We shell proceed to setup the second master database.

Similarly, we will switch off selinux and firewall.

[root@centos7-12 ~]#systemctl stop firewalld
[root@centos7-12 ~]systemctl disable firewalld
[root@centos7-12 ~]vi /etc/selinux/config

disabled

[root@centos7-12 ~]reboot

We will add a repository from MariaDB.

[root@centos7-12 ~]# vi /etc/yum.repos.d/mariadb.repo

[mariadb]
name = MariaDB
baseurl = http://yum.mariadb.org/10.0/centos6-amd64
gpgkey=https://yum.mariadb.org/RPM-GPG-KEY-MariaDB
gpgcheck=1

Install the package using YUM.

[root@centos7-12 ~]# yum clean all
[root@centos7-12 ~]# yum install MariaDB-Galera-server

At this point, we just need to configure the MariaDB config files

[root@centos7-12 ~]# vi /etc/my.cnf

!includedir /etc/my.cnf.d

Add replication parameters to server.cnf

[root@centos7-12 ~]# vi /etc/my.cnf.d/server.cnf

[galera]
# Mandatory settings
wsrep_provider=/usr/lib64/galera/libgalera_smm.so
wsrep_cluster_address=gcomm://192.168.1.11
binlog_format=row
default_storage_engine=InnoDB
innodb_autoinc_lock_mode=2
bind-address=192.168.1.12

#
# Optional setting
#wsrep_slave_threads=1
#innodb_flush_log_at_trx_commit=0

We can start the MariaDB on second node.(.12)

[root@centos7-12 ~]# service mysql start

And thats it, 2 node multi masters MariaDB clusters.