# sudo apt-get install software-properties-common
# sudo apt-key adv --recv-keys --keyserver hkp://keyserver.ubuntu.com:80 0xF1656F24C74CD1D8
# sudo add-apt-repository 'deb [arch=amd64,arm64,ppc64el] http://mirror.mva-n.net/mariadb/repo/10.3/ubuntu bionic main'
# sudo apt update
# sudo apt install mariadb-server