Scrapping NetworkManager for config files

Issues related to configuring your network
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JeffMings
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Joined: 2014/01/05 02:23:14

Scrapping NetworkManager for config files

Post by JeffMings » 2020/02/13 01:56:17

Hello All!

I am again underwhelmed by NetworkManager and want to use the ifcfg* files exclusively to set the NICs and bridge and not have to worry about anything screwing with it. E.g., I created a bridge with a lot of frustration using nmtui with eno1 slaved to it. NM decided it would be fun to add a DHCP address to the eno1 and consider the bridge "empty".

I should be able to use the more reliable method of config files by installing:
network-scripts.x86_64 : Legacy scripts for manipulating of network devices

Is there any _real_ downside to using the ifcfg* files? They have proven to be so simple and reliable in Centos7. I have reliably created bridges using SSH from a remote location countless times. If I try to do that with nmtui / nmcli, I will invariably lock myself out on single-connected-NIC boxes. I can set all of the parameters of a bridge and "underlying" physical/slave interface, review them and then "apply" them by restarting the network service. This is vastly simpler than entering a list of numerous commands and making potential errors or omissions in nmcli. Once I set a NIC, it _never_ needs to change its config automatically. NetworkManager is like a loose cannon or an additional complexity.

I know I will see the whining about deprecation. Is there anything else to watch out for if I use the config files and disable NM in Centos 8?
-Thanks.

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KernelOops
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Re: Scrapping NetworkManager for config files

Post by KernelOops » 2020/02/13 05:24:47

I think its safe to use the old network-scripts.

But it would also be a good idea, to create a test VM, that you can use to learn more about NetworkManager, test various methods of setting it up, or how to manipulate NM-controlled files. Just in case CentOS 9 has no network-scripts package :)
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TrevorH
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Re: Scrapping NetworkManager for config files

Post by TrevorH » 2020/02/13 07:24:32

There are no network-scripts in CentOS 8. The ones that are provided are all wrappers around NetworkManager which is now the only true way :-(

You can use ifcfg files but you still have NM.
CentOS 6 will die in November 2020 - migrate sooner rather than later!
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JeffMings
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Re: Scrapping NetworkManager for config files

Post by JeffMings » 2020/02/13 21:28:03

Thanks for your comments!

I was able to create a bridge without disconnecting myself from the remote server. However, I had to use nmcli commands to do it. Using nmtui to create the bridge and slave device just doesn't work correctly.

For the overwhelming majority of servers, once a NIC is set, it should NEVER change automatically. Requiring the use of multi-step tools, which are then "interpreted" by a networking service, is a very bad idea. I am _deeply_ disappointed in the design decision to require the use of NetworkManager.

-Thanks

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TrevorH
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Re: Scrapping NetworkManager for config files

Post by TrevorH » 2020/02/13 22:16:58

It is Red Hat that you need to tell. These decisions are not made by CentOS.

I hate NM and so far, everything I have seen about CentOS 8 makes me think it may be time to switch distributions. NM, firewalld, modules. They are all censored.
CentOS 6 will die in November 2020 - migrate sooner rather than later!
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 is dead, do not use it.
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jlehtone
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Re: Scrapping NetworkManager for config files

Post by jlehtone » 2020/02/14 13:06:56

Code: Select all

$ sudo yum info -q NetworkManager-config-server
Available Packages
Name         : NetworkManager-config-server
Epoch        : 1
Version      : 1.20.0
Release      : 3.el8
Architecture : noarch
Size         : 117 k
Source       : NetworkManager-1.20.0-3.el8.src.rpm
Repository   : BaseOS
Summary      : NetworkManager config file for "server-like" defaults
URL          : http://www.gnome.org/projects/NetworkManager/
License      : GPLv2+ and LGPLv2+
Description  : This adds a NetworkManager configuration file to make it behave more
             : like the old "network" service. In particular, it stops NetworkManager
             : from automatically running DHCP on unconfigured ethernet devices, and
             : allows connections with static IP addresses to be brought up even on
             : ethernet devices with no carrier.
             : 
             : This package is intended to be installed by default for server
             : deployments.
"is intended"

Is that just a hint for the admins, or does some choice in the installer make it happen too?


Overall, the RHEL is a curious mix.
On one hand all these "hands off, we'll do this for you" services for "effortless plug&pray".
On another, too limited GUI for that same "I just want to push a button" customers.


I run CentOS 6 with pure network service; NM does not enter those boxes.
Earlier CentOS 7 had to have both NM and network.service, for NM was lacking.
Now my 7 and 8 have just the NM, servers included.

Nevertheless, even though I have managed to adapt somewhat, I do understand the sentiment below:
Linus wrote: I *am* saying that "changing user interfaces and then expecting
people to change is censored stupid".

Because people who think that "we'll just redesign everything" are
actually censored censored. Really.

tunk
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Re: Scrapping NetworkManager for config files

Post by tunk » 2020/02/14 13:25:14

On a testbox I've followed the description below to disable NetworkManager.
It seems to be working, YMMV.
https://www.thegeekdiary.com/how-to-dis ... os-rhel-8/

hunter86_bg
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Re: Scrapping NetworkManager for config files

Post by hunter86_bg » 2020/02/14 14:36:45

I have been using NetworkManager since RHEL7 and I have never had your problems.

I doubt I will ever use nmtui /having in mind it started to work properly since months later -> RHEL7.1/. It sounds that you missed to configure the slave interface, or you hit a bug.
In both cases that is not supposed to happen and some steps have to be taken.

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