Mariadb Server

What we really want to set up is a galera cluster. We will use 3 systems for this.

• 192.168.1.54 mariadb (virtual IP)
• 192.168.1.55 mariadb01
• 192.168.1.56 mariadb02
• 192.168.1.57 mariadb03

Software

apt-get install mariadb-server rsync

Configuration

Set the mariadb root password.

mysql_secure_installation

Stop mariadb on all nodes.

service mariadb stop

Configure mariadb to listen on all interfaces by commenting in /etc/mysql/mariadb.conf.d/50-server.cnf.

#bind-address           = 127.0.0.1

Add the configuration for galera to /etc/mysql/conf.d/galera.cnf. Replace names so they fit the current node.

[galera]
wsrep_on=ON
wsrep_provider=/usr/lib/galera/libgalera_smm.so
wsrep_cluster_address=gcomm://mariadb01,mariadb02,mariadb03
wsrep_node_address=mariadb01
wsrep_node_name=mariadb01.kallenberg.dk
binlog_format=row
default_storage_engine=InnoDB
innodb_autoinc_lock_mode=2
wsrep_cluster_name="mariadb_galera" 
wsrep_sst_method=rsync
bind-address=0.0.0.0

On the first node the cluster is started.

galera_new_cluster

On additional nodes the service is started.

service mariadb start

Health Checks

To enable HA-proxy to be able to perform health checks, we have to create a haproxy user on the galera cluster. Requests can come from both haproxy01 and haproxy02.

create user 'haproxy'@'192.168.1.49';
create user 'haproxy'@'192.168.1.50';

References

• https://blog.cloudandheat.com/index.php/en/2016/09/09/tutorial-simple-mariadb-galera-cluster-with-haproxy-load-balancing/