[Unit]
Description=Run check_updates
OnFailure=systemd_failure_notify@%n.service
Wants=network-online.target
After=network-online.target
Requires=network-online.target

[Service]
Type=oneshot
#ExecStartPre=/bin/bash -c 'until host captiveportal.myservermanager.com; do sleep 1; done'
ExecStart=check_updates

[Install]
WantedBy=default.target