7 thoughts on - KVM Client NetworkManager Problem

• Hi,

  Just to clarify (you didn’t mention it) – do you have “NM_CONTROLLED=no” line in NICs ifcfg scripts?

  Sent from my iPhone

• I have *no* idea how you wrote that email, but STOP IT. ONLY send plain text email to this list.

  Several times, I tried to reply, and *nothing* of your email was in the reply. I had to copy and paste the original. And then I had to manually insert line breaks and “>”.

  Niederwimmer wrote:

  First, you can enable the network.service, and leave NetworkMangler disabled.

  Second, you may want to force the name for the NIC (as opposed to letting the default idiotic exy##xyx#).

  Static address: you can do that one of two ways: first, to set a static IP
  in /etc/sysconfig/network-scripts/ifcfg-exx$, or you can set it to BOOTPROTO=DHCP, but then have your dhcp server give it the same IP every time, based on its MAC address (we do that latter here).

  Hope that helps.

  mark

• Am Dienstag, 11. Dezember 2018, 15:51:58 CET schrieb Сергей Петяшков via CentOS:

  Yes I set up “NM_CONTROLLED=no” but NetworkManager create a other NIC config with DHCP ?

  The big problem is the NetworkManager, I mean there are many Problems in 1810
  update.

  So what can I do “configure”, to stop the broken configured network!

  —
  mit freundliche Grüßen / best regards,

  Günther J. Niederwimmer

• Hello,

  On my systems I have after update to last CentOS 1810 a big Problem with the network??

  Om my system I have three NIC two are connected from hardware (hostdev) the last is connected from the bridge on the host. (NetworkManager was disabled)

  Now after the update the client can’t start the NIC’s correctly :-(
  My Problem is the bridged NIC ethX

  I must Install and activate the NetworkManager or I have a LSB Error
  [ INFO ] Network Manager is not active.
  [DEPEND] Dependency failed for Network Manager Wait Online.
  Starting LSB: Bring up/down networking…
  [FAILED] Failed to start LSB: Bring up/down networking.

  But now NetworkManager create sometimes a new config for a new ethX this is configured from dhcp, but I must have a static address to connect other server
  (ldap…)

  Also the resolv.conf is overwritten and have wrong nameserver (ipv6) and duplicate search entries …

  Now it is the Problem after a reboot the network is not running correct with or without NetworkManager?

  Thanks for a answer or help,

  ————————————————————————–

  Gunter,

  I have two units that are different users with desktop KVM hypervisors CentOS 7 hosts. One had only one network card and it went through the migration from 7.5 to 7.6 without a problem. The other had three network cards and it became disabled with failed network connections. I had to rebuild the network and did so in the following manner.

  #1. NetworkManager had been turned off. I turned NetworkManger from off to on so that it would create appropriate ifcfg-* files for three network cards after a reboot.

  #2. I modified the appropriate ifcf-* files and created a new network bridge with one of the cards. After the update to 7.6 I was able to leave NetworkManager running as long as I
  had the appropriate ifcf-* file and the bridge set with “NM_CONTROLLED=no”. With CentOS
  7.5 I had to disable NetworkManager because it kept destroying the bridge even with the switch “NM_CONTROLLED=no”.

  #3. Lastly I had to change the references to the new bridge in the KVM guests.

  After this everything has worked like it did before the upgrade. My take on this is that kvm hypervisors that are set up with more than one nic card have the potential of having their network setup corrupted when the migration from 7.5 to 7.6 occurs. On a positive note NetworkManager now works with a network bridge with 7.6, but it did not work for me with 7.5.

  Good Luck!!!

  Greg

• hello Greg,

  thanks for the answer, now I am not so alone ;-)

  this Problem with the third NIC in a KVM Client is from Update to Update stronger. I mean on start the Installation “CentOS 7.0” we don’t have this Problem!

  without NetworkManager is run, on my system, I can’t start the third Network-
  Card, I have always a LSB Error on the KVM-Clients ??

  So now I found a workaround for my Problem :-(. (What are changed in the Network Configuration)

  I set up the first and second NIC to “hostdev” (hardware) this is running also before the update and set “NM_CONTROLLED=no” to this NIC’s.

  The third is a Bridge controlled Interface now is running with NetworkManager as a static Interface with “PEERDNS=no” so I have my resolv.conf is not always change and NetworkManager don’t create a new Interface with a DHCP config ??

  Why Network Manager do that with 7.6, I can’t say but I am not happy witzh this update :-(. Am Samstag, 15. Dezember 2018, 18:27:39 CET schrieb Gregory P. Ennis:

  —
  mit freundliche Grüßen / best regards,

  Günther J. Niederwimmer

• hello Greg,

  thanks for the answer, now I am not so alone ;-)

  this Problem with the third NIC in a KVM Client is from Update to Update stronger. I mean on start the Installation “CentOS 7.0” we don’t have this Problem!

  without NetworkManager is run, on my system, I can’t start the third Network-
  Card, I have always a LSB Error on the KVM-Clients ??

  So now I found a workaround for my Problem :-(. (What are changed in the Network Configuration)

  I set up the first and second NIC to “hostdev” (hardware) this is running also before the update and set “NM_CONTROLLED=no” to this NIC’s.

  The third is a Bridge controlled Interface now is running with NetworkManager as a static Interface with “PEERDNS=no” so I have my resolv.conf is not always change and NetworkManager don’t create a new Interface with a DHCP config ??

  Why Network Manager do that with 7.6, I can’t say but I am not happy witzh this update :-(.

  ————————————————————————–

  Gunter,

  You are surely not alone, there are many on this list that have a keen understanding of things with a lot of experience that provide excellent assistance. I consider myself to be a sponge absorbing everything I can, compared to most contributors on this list :)

  The migration from 7.5 to 7.6 has been somewhat painful for me too, but the work the CentOS
  team does in providing this service for us is outstanding. Most of the time these upgrades are just a ‘blink’ and the machines that upgrade have no problems. However, I do have to admonish myself from time to time with the encouragement of ‘it is time to learn’, and I
  have a lot that I can learn.

  Good Luck!!!!!

  Greg

• To disable the fiddling of the tools with your /etc/resolv.conf, you can add this to disable it. Works for the init scripts and NetworkManager:

  RESOLV_MODS=”no”

  Regards, Simon