[CentOS] NetworkManager fights with DHCP-only backup NIC

[Warren Young]

On Dec 2, 2014, at 2:34 PM, Les Mikesell <lesmikesell at gmail.com> wrote:

> On Tue, Dec 2, 2014 at 3:17 PM, Warren Young <wyml at etr-usa.com> wrote:
>> On Dec 2, 2014, at 2:10 PM, Les Mikesell <lesmikesell at gmail.com> wrote:
>> 
>>>> Think 'laptop'.
>>> 
>>> Why would you need a static IP to stick to a laptop?   Or have
>>> multiple NICs on one?
>> 
>> Wired and WiFi.
>> 
>> If you configure a static IP with the wired Ethernet plugged in, you probably want that static IP to continue being used when you unplug the Ethernet cable and NM switches you over automatically to WiFi.  NM does this.
> 
> 
> Really?  That's insane.  Our wired jacks are not on the same subnets
> as our access points.   I'm not sure that's even possible with the
> Cisco units that have separate controllers.

In such a network, you won’t run static IP configuration on such boxes.  You’ll use DHCP.

On my home LAN, this automatic static IP migration is *exactly* what I want on my laptop.

The current NetworkManager design isn’t unequivocally wrong.  It’s a sensible default for Fedora.  It’s just not the right choice for enterprise Linux servers.

If you want to go and argue that Fedora shouldn’t be driving CentOS, it’s not an impossible position to take, but you have to fill in the blank spot it leaves.  What would drive CentOS instead?

>> This is why I want a checkbox in the NM GUI: “This is a 4U server, dummy, not a laptop.”
> 
> How about just 'don't be stupid’ ?

More like “Don’t be clever, NetworkManager, I’m better at it.”