Galera Cluster

Setup the Cluster

Install the packages

On each node do as root:

• Add sources

# cat > /etc/apt/sources.list.d/mariadb.list << EOF
# MariaDB Server
# To use a different major version of the server, or to pin to a specific minor version, change URI below.
deb [arch=amd64] http://downloads.mariadb.com/MariaDB/mariadb-10.5/repo/ubuntu $(lsb_release -cs) main

deb [arch=amd64] http://downloads.mariadb.com/MariaDB/mariadb-10.5/repo/ubuntu $(lsb_release -cs) main/debug

# MariaDB MaxScale
# To use the latest stable release of MaxScale, use "latest" as the version
# To use the latest beta (or stable if no current beta) release of MaxScale, use "beta" as the version
deb [arch=amd64] https://dlm.mariadb.com/repo/maxscale/latest/apt $(lsb_release -cs) main

# MariaDB Tools
deb [arch=amd64] http://downloads.mariadb.com/Tools/ubuntu $(lsb_release -cs) main
EOF

• Install the packages

# apt update
# apt install mariadb-server mariadb-backup galera-4

Setup certificates for the cluster comunication

Make a CA certificate

Make a CA certificate with a very long lifetime as you dont want to make normal certificate updates at this point.

$ subject='/C=DE/ST=Hamburg/L=Hamburg/O=Organisation/OU=Databases/CN=Galera Cluster'
$ openssl req -new -x509 -nodes -days 365000 -newkey rsa:4096 -sha256 -keyout ca-key.pem -out ca-cert.pem -batch -subj "${subject}"

Create a certificate for each cluster node

$ for node in {1..4}
do
  emailAddress="dbadmin@server.de"
  servername="maria-${node}.server.de"
  subject="/C=DE/ST=Hamburg/L=Hamburg/O=Organisation/OU=Databases/CN=${servername}/emailAddress=${emailAddress}"
  openssl req  -newkey rsa:4096 -nodes -keyout ${servername}-key.pem    -out ${servername}-req.pem -batch -subj "${subject}"
  openssl x509 -req -days 365000 -set_serial $(printf "%02d" "${node}") -in  ${servername}-req.pem -out ${servername}-cert.pem -CA ca-cert.pem -CAkey ca-key.pem
done

Copy keys and certificates to the nodes

Copy the specific keys and certs to each node:

$ sudo mkdir --mode=0700 /etc/mysql/priv # put in here: maria-${node}.server.de-key.pem
$ sudo mkdir --mode=0750 /etc/mysql/cert # put in here: maria-${node}.server.de-cert.pem , ca-cert.pem

Configure the MariaDB Galera Cluster

Show wsrep_provider_options

$ mariadb -NBABe 'show variables like "wsrep_provider_options"' | awk '{gsub(/$/,":\n",$1); gsub(/(;|$)/,";\n"); printf $0; }'