Systemd ping daemon

ping@.service

[root@stage ~]# cat /etc/systemd/system/ping@.service
[Unit]
Description=One time ping check of host %I
After=network.target

[Service]
Type=forking #forking makes the unit stay in starting state until ping finishes. oneshot does not work with RemainAfterExit, while type simple makes the unit started as soon as ping starts, which is something we DON'T want
Restart=on-failure
ExecStart=/bin/ping -q -c 5 %i
RemainAfterExit=true

[Install]
WantedBy=multi-user.target

#

systemctl enable ping@remotehost

#

systemctl edit --full some-service-that-needs-external-connectivity
After=ping@remotehost
Requires=ping@remotehost