This service provides a mysql server and nothing more!
iocage fetch --plugin-name "mariadb" --git_repository https://github.com/m1ch/iocage-plugin-index --branch mariadb --name mariadb vnet=On dhcp=Off nat=On
iocage destroy --recursive mariadb
iocage exec mariadb bash -c 'PASS=$(</root/mysqlrootpassword); mysql -u root -p"${PASS}"'
iocage exec mariadb bash -c 'PASS=$(</root/mysqlrootpassword); mysql -u root -p"${PASS}" -e "SHOW DATABASES"'
or
iocage exec mariadb bash -c 'PASS=$(\</root/mysqlrootpassword); mysql -u root -p"${PASS}"' << EOF
SHOW DATABASES;
USE MYSQL;
SHOW TABLES;
EOF
set jail_name=mariadb
set socket=`zfs list -o mountpoint | grep "iocage/.*${jail_name}/root" | head -n 1`/var/run/mysql
iocage exec second_jail mkdir /var/run/mysql
iocage fstab -a second_jail $socket /var/run/mysql nullfs ro 0 0