On 04/06/2012 06:23 PM, zxq9 wrote:
> On 04/07/2012 03:28 AM, Konstantin Olchanski wrote:
>> I tend to think that these days one should go back to static IP addresses
>> for server-type machines, after all, all DHCP, network manager&   co do is assign
>> the same IP address to the same machine over and over and over again with the only
>> variation when they fail to do the boring thing and you have a machine down, staying
>> down until somebody physically walks to it to reboot it.
>
> Do you mean there are serious networks that use DHCP by default for
> systems other than transient network guests residing in their own little
> subnet (like laptops)? And server IP assignment by DHCP... I can't
> believe this is really done, or am I being naive about naivete?

It is really being done.  I do it for 150+ Linux workstations at work across several subnets.  For 10 systems I might not care, but manual host-specific configurations are time-consuming to manage.  95% of my boxes are identical (that itself is a challenge), replicable from bare metal to deployment (via kickstart and lots of scripting).

> That just sounds like a recipe for disaster for a lot of reasons.
> Without some thought and preparation any network setup is doomed to get
> wacky after a while, and maybe I'm just being too old school -- but
> being explicit about setup I've never had a single network problem like
> the ones described here, whether letting NM run the show or using the
> older networking subsystem.


IMHO, there is no better way than to use DHCP for centralized administration of all the network parameters.  We distribute: IP (statically assigned based on Ethernet), NIS servers, NIS domain, default router, netmask, netbios servers, PXE boot params, DNS servers, NTP servers, and hostname.

When we changed our central DNS servers, I didn't have to change every host, I just changed my DHCP server config file and let the clients pick up the change when they renewed the lease.  Seamless and easy.  If I need to change a host or IP, I just edit the dhcpd.conf file and reboot...great for prepping new deployments to replace existing systems.

That said, I have seen a few bugs with NetworkManager on EL6 where we've had a switch go down (bad UPS battery) and a couple clients have gone offline, where they should have tried to bring the net back up.  The few Fedora boxes and EL5 systems running NM have not had these issues.  But those are BUGS that should be replicated, debugged and fixed, otherwise the world won't improve.

And we don't allow any 'guests' on our networks; we never hand out dynamic addresses for accountability and policy-based reasons.

Just thought I'd toss out another perspective -- it works for us quite well, and surely there are better methods we could apply too, but that's for another day.

Regards,
chris