A failure was seen in
repository installation script on ubuntu.
The failure is related to the script not finding the MariaDB public key mariadb-keyring-2019.gpg
W: http://archive.ubuntu.com/ubuntu/dists/bionic/InRelease: The key(s) in the keyring /etc/apt/trusted.gpg.d/mariadb-keyring-2019.gpg are ignored as the file is not readable by user '_apt' executing apt-key.
Apparently the default umask 0022 assumption by the script creates a problem on hardened systems with umask 0027.
ls -l /etc/apt/trusted.gpg.d/mariadb-keyring-2019.gpg -rw-r----- 1 root root 43345 Mar 3 16:44 mariadb-keyring-2019.gpg