On Sun, Dec 9, 2012 at 6:38 PM, Tom H <[log in to unmask]> wrote:
> On Sun, Dec 9, 2012 at 5:21 PM, Nico Kadel-Garcia <[log in to unmask]> wrote:
>> On Sun, Dec 9, 2012 at 11:05 AM, Eero Volotinen <[log in to unmask]> wrote:
>>> 2012/12/9 José Pablo Méndez Soto <[log in to unmask]>:
>>>> Hello,
>>>>
>>>> I am playing around with SL instead of CentOS so to know which one behaves
>>>> better or just to have a criteria on how they both differ, being RedHat
>>>> re-distros.
>>>>
>>>> I noticed that my virtual machine with GUI, that I built from the
>>>> SL-63-x86_64-2012-08-02-Install-DVD.iso, won't reply to pings or open SSH
>>>> sessions until a user logs in.
>>>>
>>>> I tried the same on a CentOS  6.2 built similarly, and no matter if there
>>>> are users or no users logged in, it always have networking and you can SSH
>>>> into it.
>>>>
>>>> Any idea about this difference? Can it be changed in SL so to initiate
>>>> connections before a GUI log in?
>>>
>>> On RHEL 6 and clones, network is managed by network-manager by
>>> default. You need to disable network manager and configure interfaces
>>> on traditional way.
>>>
>>> Take look at NM_MANAGED on /etc/sysconfig/network-scripts/ifcfg*
>>
>> NetworkManager is *not the friend* of anyone running a server. It's
>> unfortunately difficult to rip out by the roots, because other
>> components depend on it. And the "system-config-network" tool has no
>> way to gracefully turn it off, you have to use a text editor.
>>
>> You can put "NM_MANAGER=no" in /etc/sysconfig/network, along with
>> "NO_ZEROCONF=yes" to aovid generating those default, irritating
>> "169.254.*" IP addresses at network startup time.
>
> "NM_MANAGER=no" in /etc/sysconfig/network?
>
> You must mean NM_CONTROLLED.
> Are you sure that you can set it in "/etc/sysconfig/network"?

Yes, quite right. It's already been a day....

If you look at the /ets/sysconfig/network-scripts maze of twisty
little scripts, all different, you'll see that most of the "ifup",
"ifdown", and similar executable scripts actually source
"/etc/sysconfig/network" somewhere in their actual operation. So yes,
"/etc/sysconfig/network" actuall works to shut down NetworkManager
without having to maintain and edit individual components.

Unfortunately, if you don't read the source code, you won't know about
this sort of thing.

> I thought that it was meant to be used in
> "/etc/sysconfig/network-scripts/ifcfg-*".

It's like turning off the circuit breakers. You're not relying on the
local switch for individual channels, and it's much safer in case you
re-arrange the network in the future (by adding network ports,
replacing a network card, or cloning a virtual machine).

> (I've never had a problem removing NM from an X-less box.)

And on a machine that's a pure LAMP stack, DNS server, or other pure
server that can work.