BRINGING UP LOOPBACK INTERFACE: RTNETLINK answers: File exists / OPERATION NOT SUPPORTED

One of our VPS suddenly not showing when running the command ifconfig Also while restarting network, I was getting the following error.

OpenVZ – RHEL/CentOS 6.5 Container Networking Bug

No active network interfaces:

[root@vps ~]# ifconfig
[root@vps ~]#

 [root@vps ~]# /etc/init.d/network restart
Shutting down loopback interface:                          [  OK  ]
Bringing up loopback interface:  RTNETLINK answers: Operation not supported
Failed to bring up lo.
[FAILED]
Bringing up interface venet0:  RTNETLINK answers: Operation not supported
Failed to bring up venet0.
[FAILED]
RTNETLINK answers: File exists
RTNETLINK answers: File exists
RTNETLINK answers: File exists
RTNETLINK answers: File exists
RTNETLINK answers: File exists
RTNETLINK answers: File exists
RTNETLINK answers: File exists
RTNETLINK answers: File exists
RTNETLINK answers: File exists

Fix : The issue was with iproute package. The package got updated automatically and it was not excluded in yum updates. To fix the issue, you need to downgrade the package iproute.

How to solve (CentOS 6 64Bit):

Until the OpenVZ developers create an official fix, you can downgrade the iproute package as follows:

1. From your OpenVZ Hostmachine, download the old RPM:

[root@vps ~]#  wget http://repo.smartservermanagement.com/misc/iproute-2.6.32-23.el6.x86_64.rpm

2. Copy this inside the container:
[root@vps ~]#  cp /root/iproute-2.6.32-23.el6.x86_64.rpm /vz/private/<CTID>/root/

3. Console into the VPS, forcefully remove the current iproute package, and replace with old one:

[root@vps ~]#  vzctl enter <CTID>
[root@vps ~]#  rpm -e iproute-2.6.32-31.el6.x86_64 –nodeps
[root@vps ~]# rpm -ivh /root/iproute-2.6.32-23.el6.x86_64.rpm

4. Restart the network service

[root@vps ~]# service network restart

Don’t forget if you have automated yum updates configured (e.g. cPanel does this), add iproute* to the exclude= line in /etc/yum.conf for the time being.