> On 09/02/2020 23:55, Nicolas Kovacs wrote: > > Hi Nicolas, > > [snip] > >> Maybe there's a reason to make NetworkManager more or less mandatory >> from now on, but I don't see it. So I thought I'd rather ask on this >> list. > > Like you, I read about NetworkManager becoming the default tool for > CentOS 8. So I sat down with a colleague to figure out how we could use > NetworkManager, and convert our existing network configs (on CentOS 6 > and 7) to work with NetworkManager. > > I'm sad to report that we ran into at least 3 issues (listed below). We > found solutions to the first two, but the last one was a show-stopper, > and we came to the conclusion that for servers, NetworkManager is still > overkill, and for us, actually unusable. So even on CentOS 8, we will > keep using the legacy scripts. > > 1. When NetworkManager activates interfaces, it does not wait for IPv6 > DAD to complete. This makes systemd reach the "network-online" target > before IPv6 is fully initialised, and some daemons fail to start. We > eventually found a work-around, but not before I'd lost some of my hair. > > 2. NetworkManager doesn't know how to activate dummy interfaces from > ifcfg-dummy* files. You have to create dummy interfaces directly in > NetworkManager. This is not a problem on CentOS 8, but on CentOS 7, > there is a subtle issue with loading the dummy module that makes things > fail at boot. We again found the solution, but it's annoying that none > of it was documented. > > 3. Some of our servers run full routing daemons (BIRD), and have > multiple route tables. On these, when we start NetworkManager, it > attempts to read the entire route tables into memory using the netlink > API. This makes it log lots of errors. Then, NetworkManager's RAM usage > goes up and up, going to over 3 GB!! Finally, it barfs and dies. And > then systemd starts it again, and it goes and does the same. > > We have NOT been able to find any solution to this stupidity of > NetworkManager. And so we have made the choice to abandon it, and remain > with legacy network scripts.Thanks for confirming that NetworkManager is not the solution for everyone. To me it seems that NetworkManager was developed by laptop users for laptop users and that's why it is what it is today. Useful for laptops/desktops and simple server setups. Unfortunately, instead of fixing/refactoring the whole bash networking script mess, another new project was started instead, called systemd-networkd :-) Regards, Simon
On Tue, Feb 11, 2020 at 06:11:04AM +0100, Simon Matter via CentOS wrote:> Thanks for confirming that NetworkManager is not the solution for > everyone. To me it seems that NetworkManager was developed by laptop users > for laptop users and that's why it is what it is today. Useful for > laptops/desktops and simple server setups.I've mentioned on this list countless times about how NetworkManager is actually pretty good for a general server. Automatic link detection and activation/deactivation, a dispatch service on link activation/deactivation, support for bringing up secondary interfaces after a primary goes up, a dbus interface for automation, etc.> Unfortunately, instead of fixing/refactoring the whole bash networking > script mess, another new project was started instead, called > systemd-networkd :-)Actually, I'm sad that RHEL/CentOS 8 doesn't support systemd-networkd. It's really nice, especially for really pared down systems that don't need a lot of extra services like NetworkManager. But I understand that Red Hat needs to focus its support efforts. -- Jonathan Billings <billings at negate.org>
On Tue, Feb 11, 2020 at 8:12 AM Jonathan Billings <billings at negate.org> wrote:> > On Tue, Feb 11, 2020 at 06:11:04AM +0100, Simon Matter via CentOS wrote: > > Unfortunately, instead of fixing/refactoring the whole bash networking > > script mess, another new project was started instead, called > > systemd-networkd :-) > > Actually, I'm sad that RHEL/CentOS 8 doesn't support > systemd-networkd. It's really nice, especially for really pared down > systems that don't need a lot of extra services like NetworkManager. > But I understand that Red Hat needs to focus its support efforts. >I thought that systemd was under redhat, so I am confused why they would not be pushing it instead of networkmanager. Am I missing something?
Le 11/02/2020 ? 14:11, Jonathan Billings a ?crit?:> I've mentioned on this list countless times about how NetworkManager > is actually pretty good for a general server. Automatic link > detection and activation/deactivation, a dispatch service on link > activation/deactivation, support for bringing up secondary interfaces > after a primary goes up, a dbus interface for automation, etc.I just prepared myself to catch up and learn more about NetworkManager. So I opened my big fat "Unix and Linux System Administration Handbook 5th edition", with a text file open on the computer to take extensive notes... ... only to find out that there is only half a page on NetworkManager in this book. Allow me to quote it: "NetworkManager is primarily of use on laptops, since their network enviromment may change frequently. For servers and desktop systems, NetworkManager isn't necessary and may in fact complicate administration. In these environments, it should be ignored or configured out." Hmmmm. -- Microlinux - Solutions informatiques durables 7, place de l'?glise - 30730 Montpezat Site : https://www.microlinux.fr Mail : info at microlinux.fr T?l. : 04 66 63 10 32 Mob. : 06 51 80 12 12