Start NRPE after openvpn tunnel is connected

NRPE will not start if its server address is a openvpn ip and the tunnel is not yet established when NRPE tries to start. to solve this. create a new systemd file

systemctl -all | grep ovpn
cp /usr/lib/systemd/system/nrpe.service /etc/systemd/system/nrpe.service

Add your tun device to Requires and After. Note you need the systemD name of your tune device. in this case. OpenVPN was configured to use tun ovpn-gwSamuel check systemctl for its correct name. The result should look something like this. Notice the esacped dash sign in the name.

[Unit]
Description=Nagios Remote Program Executor
Documentation=http://www.nagios.org/documentation
Conflicts=nrpe.socket
Requires=network.target sys-devices-virtual-net-ovpn\x2dgwSamuel.device
After=network-online.target sys-devices-virtual-net-ovpn\x2dgwSamuel.device

[Install]
WantedBy=multi-user.target

[Service]
Type=forking
User=nrpe
Group=nrpe
EnvironmentFile=/etc/sysconfig/nrpe
ExecStart=/usr/sbin/nrpe -c /etc/nagios/nrpe.cfg -d $NRPE_SSL_OPT