Re: [gentoo-user] root on nfs and multiple ip addresses

[William Kenworthy]

On 17/3/21 3:46 pm, J. Roeleveld wrote:
> On Wednesday, March 17, 2021 7:31:52 AM CET William Kenworthy wrote:
>> Hi,
>>
>> I have just reinstalled my 32 bit Gentoo on a raspberry pi 3B with a
>> Gentoo aarch64 image also with boot on an sdcard and root on nfs (both
>> working fine with boot on an sdcard and root on an nfs share hosted on
>> an moosefs cluster).  Both have a problem where the initial boot loader
>> requests an IP address using "IP=dhcp", then the main operating system
>> requests it again on initialising the interface.  Despite asking using
>> the same MAC address, ISC dhcp issues a new and different IP address -
>> this seems counter intuitive so why is it happening?  Have I missed a
>> configuration option somewhere?
>>
>> The standard advice is to stop the OS requesting an address (Ubuntu and
>> the like) - but shouldn't dhcp know that its already issued a valid IP
>> address to that MAC address?
>>
>> BillK
> Normally I get the same IP, but not if the lease is expired:
>
> What is the "default-lease-time" and "max-lease-time" set to on your DHCP
> server?
>
> Or it gets "released", which can happen when the client informs the DHCP
> server it no longer needs the IP.
>
> Also, why not fix the IP for the MAC on the DHCP server?
>
>
Hi Joost, I have been moving away from fixed IP's using scripts to
update via dynamic DNS (which is why two IP numbers per MAC are
problematic).  I might fix it on the DHCP server to see what happens. 
The lease times are relatively long considering the boot time. 
Interestingly, dhcp issues the same IP addresses consistently to both
the boot process and OS.  While stopping the OS requesting an address is
easy enough ... the question is why is that necessary.  Google shows a
number of recommendations and howtos saying to do just that but it seems
a "kludge".

BillK