dhcpcd-discuss

On 15/12/2020 03:34, msg board wrote:
> I have multiple interfaces on my machine. I was hoping command_args="-d -j 
> /var/log/dhcpcd.log --waitip=4 -c /usr/libexec/dhcpcd-run-hooks" in 
> /etc/openrc.d/dhcpcd will bring up all of them at boot. But it did not as I 
> write in previous post. I changed this to command_args="-d -j 
> /var/log/dhcpcd.log --waitip=4 eth3" and eth3 comes up at boot without any 
> errors (eth3 has ethernet cable connected in this scenario) . However I am not 
> sure where the ethernet cable may be connected in future amongst the 4 
> interfaces that I have, therefore I changed it to command_args="-d -j 
> /var/log/dhcpcd.log --waitip=4 eth0 eth1 eth2 eth3" and again I get error
>
> eth0 : no valid interfaces found
> eth1 : no valid interfaces found
> eth2 : no valid interfaces found
> eth3 : no valid interfaces found
>
> Even when ethernet is connected to eth3, it does not come up with 
> command_args="-d -j /var/log/dhcpcd.log --waitip=4 eth0 eth1 eth2 eth3" .
>
> So, I created 4 different startup scripts.
>
> /etc/openrc.d/dhcpcdeth0 which has command_args="-d -j /var/log/dhcpcd.log 
> --waitip=4 eth0"
> /etc/openrc.d/dhcpcdeth1 which has command_args="-d -j /var/log/dhcpcd.log 
> --waitip=4 eth1"
> /etc/openrc.d/dhcpcdeth2 which has command_args="-d -j /var/log/dhcpcd.log 
> --waitip=4 eth2"
> /etc/openrc.d/dhcpcdeth3 which has command_args="-d -j /var/log/dhcpcd.log 
> --waitip=4 eth3"
>
> Now when ethernet cable is connected to anyone, that interface comes up and the 
> rest also comes up, but without any IP as there is not ethernet cable connected 
> to other 3 interfaces. However, after boot, only dhcpcdeth3 (the one on which 
> cable is connected) is running. All other dhcpcd instances show stopped. 
> Therefore, if I disconnect cable from eth3 and connect it to e.g. eth1, I cannot 
> see eth1 with IP automatically
>
> So,
>
> 1) How do I specify multiple ethernet interfaces on a single instance of dhcpcd 
> (or single command_args commandline of dhcpcd) so that only one instance of 
> dhcpcd manages all the interfaces
> 2) How do I specify arguments such that after removing ethernet cable from one 
> instance to another, the new interface gets IP address automatically.
>
> Please let me know if any of this is possible and how. I will report my findings 
> if I am able to figure out myself. Thank you for your time


It's perfectly possible.
I generally debug with this:
	dhcpcd -dB

and dhcpcd will try and manage all interfaces by default.
I suspect udev is at fault on your machine, disable it with nodev please.

Roy