Setting up a Galera MariaDB Cluster

How to setup a Galera MariaDB Cluster

Remove any existing packages:

yum remove maria*

Update:

yum update

Add the official repo for MariaDB by creating the file /etc/yum.repos.d/MariaDB.repo

[mariadb]
name = MariaDB
baseurl = http://yum.mariadb.org/10.1/centos7-amd64
gpgkey=https://yum.mariadb.org/RPM-GPG-KEY-MariaDB
gpgcheck=1

Now install MariaDB:

yum install -y MariaDB-server MariaDB-client MariaDB-compat galera socat jemalloc

Setup MariaDB:

systemctl start mariadb
mysql_secure_installation
systemctl stop mariadb

To generate the CA certificate:

openssl genrsa 2048 > ca-key.pem
openssl req -new -x509 -nodes -days 3600 -key ca-key.pem -out ca.pem

To generate the server certificate, remove passphrase, and sign it:

openssl req -newkey rsa:2048 -days 3600 -nodes -keyout server-key.pem -out server-req.pem
openssl rsa -in server-key.pem -out server-key.pem
openssl x509 -req -in server-req.pem -days 3600 -CA ca.pem -CAkey ca-key.pem -set_serial -1 -out server-cert.pem

(Optional) To generate the client certificate, remove passphrase, and sign it:

openssl req -newkey rsa:2048 -days 3600 -nodes -keyout client-key.pem -out client-req.pem
openssl rsa -in client-key.pem -out client-key.pem
openssl x509 -req -in client-req.pem -days 3600 -CA ca.pem -CAkey ca-key.pem -set_serial 01 -out client-cert.pem

Edit the file: /etc/my.cnf.d/server.cnf

[sst]
encrypt=4
ssl-ca=/etc/pki/ca.pem
ssl-cert=/etc/pki/server-cert.pem
ssl-key=/etc/pki/server-key.pem

[galera]
wsrep_on=ON
wsrep_provider=/usr/lib64/galera/libgalera_smm.so
wsrep_cluster_address='gcomm://a.a.a.a,b.b.b.b,c.c.c.c'
wsrep_cluster_name='cluster.name'
wsrep_node_address='10.0.0.11'
wsrep_node_name='node1'
wsrep_sst_method=rsync
wsrep_sst_receive_address='x.x.x.x'
wsrep_provider_options='socket.ssl_key=/etc/pki/server-key.pem;socket.ssl_cert=/etc/pki/server-cert.pem;socket.ssl_ca=/etc/pki/ca.pem;evs.inactive_timeout=PT45S;evs.install_timeout=PT45S;evs.keepalive_period=PT3S;evs.max_install_timeouts=8;evs.send_window=512;evs.suspect_timeout=PT30S;evs.user_send_window=256;'
binlog_format=row
default_storage_engine=InnoDB
innodb_autoinc_lock_mode=2

In the file above the line “wsrep_sst_receive_address=’x.x.x.x'” is required if any of the nodes are behind a NAT router on private IP addresses, where x.x.x.x is the public IP address of the router. Without this SST donors will try to send snapshot data to the nodes private IP address which will invariably fail.

The “wsrep_provider_options” are tailored to for nodes that talk to each other over a WAN (i.e. the internet). If your nodes are all on the same LAN then you can leave this option out completely – it adjusts some timeout default values to better cope with varying connectivity quality across a WAN.

Start the primary node:

galera_new_cluster

Start the other nodes:

systemctl start mariadb

show status like 'wsrep%';