Network Manager...why?, for a minimalist server installation

For a minimalist server installation, why do I need Network Manager? Is there a serious technical benefit that the Network Manager provides?

If not, is there a way I can get rid of it and just use the network-scripts like I've always done?

thx

You should be able to uninstall it and just connect from the terminal, or with a start up script. I always liked the famous Sidux program that was pretty much invisible if you wanted it to be. Can't remember the name right now. We do this in Slackware too....so it "just connects" with scripting(IF Up, Down, etc). But, yes, I would just uninstall "NetworkManager" which I think, will only remove the GUI layer. Redman?

Strip that thing out. First thing I do every time on a desktop system.

I use wicd on laptops now it really is excellent if you havn't tried it. Network Manager is a proper pain in the backside imho. If you need vpn or dial-up or something then i suppose you might want it, but it causes so many problems I don't think it's worth it. Google around on linux forums for network problems and NM crops up again and again.


john - was it wpa_cli on sidux?

This post has been edited by spoovy: Aug 6 2011, 04:02 AM

Ceni ? something like that...I used to use it, then just use a standard panel applet for wifi if I wanted some visuals

During installation you can configure Network for Lan (eth1) and Internet (eth0) depending on your configuration. In Sceintific Linux 6.1 this will start the NetworkManager (not for Basic Server). to bring up the interfaces you need to provide the following command:
ifup eth1
ifup eth0

Similarly for bringing down the interfaces:
ifdown eth1
ifdown eth0

@john - yeah it was ceni. Very good. Shame to see sidux circling the drain these days, I really liked that project.

Back on topic, it seems that NetworkManager is the future of networking for TUV so we'd all better start getting used to it. (taken from the TUV6 Deployment Guide -

This post has been edited by spoovy: Aug 6 2011, 05:04 AM

And right you are. I didn't particularly care for NM myself (I still don't really like it that much), but this was really a case of my not wishing to learn something else new to get consistent results across the network. A lot of other things changed in Fedora, and later EL sort of at once, and this was just one more thing to deal with.

You can turn off NM and use the old-fashioned networking utilities, but I recommend against it, as it is considered a stale technology at this point.

For the SL 6x I don't think systemd will rear its head at all (and hopefully will be a nice piece of work by the time 7.0 comes around), so for the duration of 6x you should be able to use NM without having to change anything once you learn it (under systemd "ethX" becomes "emZ", and that can break ifup~ scripts, which is unneccessarily annoying in my opinion, but whatever).

Some tips on learnig to live with NM in a server setting (it generally "just works" on laptops and desktops -- unless you have a Dell for some reason):

/etc/sysconfig/networking-scripts/

• Your NM configurations all live in /etc/sysconfig/network-scripts/ and are named ifcfg-$INTERFACE by default (and remember, an interface is not the same thing as a device, a concept that comes naturally with wireless but is hard to remember at first with wired networks). Reading these files is easy and there is a tag reference here: http://man-wiki.net/index.php/5:ifcfg (this is not a Fedora/EL reference, so /etc/sysconfig/network/ifcfg-* == /etc/sysconfig/network-scripts/ifcfg-* here)
• Defaults for NM as a subsystem can be changed in /etc/NetworkManager/NetworkManager.conf, but I strongly advise against this. The defaults are sane already and if you mess with things you will be on your own troubleshooting problems in most cases.
• Don't expect the contents of /etc/sysconfig/network-scripts/ifcfg-ethX to be accurate if you have a minimal installation and are running a dedicated server. Most server setups have static IPs, at least across the LAN, and this has to be set manually (I find post install to be better than during installation for servers) because the default is to make DHCP requests at every "ifup". Most servers have somewhat unique networking requirements anyway, so expect a manual configuration if you want things to work right.
• Without a GUI applet to play with, NM can be confusing for an administrator who has only dealt with NM via the desktop.
• The ifconfig is not the same ifcfg. man ifcfg before you run off typing a lot of weird ifcfg commands on a remote system you can't physically access. I loved ifconfig because of familiarity, but keep in mind that its deprecated and if you are new to deeper networking I recommend learning the newer stuff, as you will be forced to by the time 7.0 comres out anyway. These sort of minor systems are like highschool girlfriends anyway: Don't get too attached to any particular one; most of them wind up behaving about the same and will be temporary anyway.

NM does not go to any pains to take care of hostname foo.bar.com calls and hostnames are stored all over the place in different ways that can make otherwise simple network utilities fail. For example, rpcgssd, sssd, krb5kdc, kadmind, rpcidmapd etc. all take the local hostname and pass it to their server counterparts which then check the value the client daemon thinks is correct against what a reverse DNS query on the requesting IP says. If the values don't match, then things don't work. The client daemons will try pulling the hostname from a few places: /etc/hosts, /etc/sysconfig/network and a call to hostname to get the current environment variable. If these say different things expect something in the daemon chain to not work correctly (one might derive the value one way while another gets it from somewhere else, depending on how old the mesh of versions you're running is).

To avoid problems of this sort:

• Check /etc/hosts and make sure that the real hostname is not set there (you only want "localhost.localdomain localhost" / "localhost6.localdomain6 localhost6" type entries there for 127.0.0.1 and ::1 ). NM will often append the hostname to ::1 and screw this up for you.
• If you have ever changed hostnames (or even set it one way during install and then set it a different way in an ifcfg-* file) then check your /etc/sysconfig/network file and make sure things line up or things will still fail.

For wired networks ifconfig or nm-tool will show you both the current/defaukt interface names (eth0, eth1, ethX, whatever, which can change with the whims of udev, so...) and, critically, what the MACs are. If you're not aliasing/spoofing MACs (as in, dodging banhammers without proxies) then the MAC can be more useful than the ethX naming scheme if you have a load of wired interfaces on a single card, so one of the keys to making NM work well for you in multi-interface situations is to include the MAC address in the ifcfg-* file for the interface. Note also that because you can declare the device name inside the ifcfg file, the name of the ifcfg file can be almost anything, but it is best to keep the file name and the device name consistent (this is the type of thing you are guaranteed to forget 6 months later).

Learning the ifcfg file tags, how to use the command-line utilities to get necessary information, and knowing where to check to make sure your hostname variable is consistent will make about 90% of network setups pretty easy without resorting to disabling NM. Its a bit like SELinux in this regard. A lot of folks disregard it and just turn it off because they don't understand where to start to get their head wrapped around it and so just shut it off (sometimes recent Windows converts do the same thing with file permissions when trying to set up web or file servers, heading straight for chmod -R 3777 /var/* once they find out they can do that, which is equivalent to shutting off SELinux from a certain perspective).

Sorry for posting a book's worth of text. I really should have just written a blog post and linked it instead of being a wall-texter, I suppose.

To disable NetworkManager:

# service NetworkManager stop

To disable NetworkManager during startup
#chkconfig NetworkManager off

Ensure that the interfaces are not NM_Controlled..

# vi /etc/sysconfig/network-scripts/ifcfg-eth0 ...eth1 etc....

NM_controlled = no


and
ONBOOT=yes

to start the interfaces during boot...