CentOS: Delay eth1 until eth0 is up

Ghostwheel · 04-18-2019, 10:47 AM

I have a VPN using eth1 but requires eth0 to be up first so it can connect.

I can set a delayed cron script to force a reconnect but that is pretty hacky and distateful.

Is there a way to either delay eth1 from starting for x seconds or, ideally, delay it until eth0 is started and connected?

wolfperkins · 04-18-2019, 12:22 PM

You could change the /etc/sysconfig/network-scripts/ifup-eth system script to insert a delay for any ${DEVICE} other than eth0 like so:

if [ "${DEVICE}" != "eth0" ]; then
is_available_wait eth0 ${DEVTIMEOUT} || {
net_log $"Device eth0 does not seem to be present, delaying initialization of ${DEVICE}."
exit 1
}
fi

One caveat is you would need to edit the script on every update of the initscripts package.

szboardstretcher · 04-18-2019, 01:18 PM

Systemd should be able to accomlish this as well. Although I don't remember how, off the top of my head.

jefro · 04-18-2019, 03:12 PM

"I have a VPN using eth1 but requires eth0 to be up first so it can connect." Seems odd to me. Wonder why it could do that?