Installing from repo:
---------------------

    sudo sh -c 'cat >/etc/apt/sources.list.d/osso-aptly.list' <<EOF
deb [signed-by=/etc/apt/keyrings/osso-aptly.gpg] http://aptly.osso.io/cumulus/ cumulus3 main
EOF

    sudo apt update
    # (yields: public key is not available: NO_PUBKEY 9794ED215423E1D2

    sudo wget -qO /etc/apt/keyrings/osso-aptly.gpg https://aptly.osso.io/app+aptly.osso.nl.gpg
    sha256sum /etc/apt/keyrings/osso-aptly.gpg | sed -e 's/\(......\)/\1 /g;s/  .*//'
    # yields: 0c5015 c5b5a4 8eb82c f349bf 73f421 ebb485 5ed209 77ecef f772ff fc8cc1 d43b

    sudo apt update

    sudo apt install cumulus-tools frr