Help: IP address gone after reboot

[wdli]

Hi,

I am using a Centos 7.2 server with kernel version 3.10.0-514.21.1.el7.x86_64 x86_64 GNU/Linux. There is a 10G interface "eno49" that is connected to a switch for networking. It can be configured both as static or using DHCP but the problem is the same. The NetworkManager has been removed before this by someone else for reasons I don't know about. I can provide more info if required on the server.

For the first time after install I had to do a bunch of patchings for security findings including kernel patching. After reboot, the original IP address on "eno49" is gone. I had to manually do "ifup eno49" to bring it back. But next reboot the same problem would repeat even with static IP. Before patching there were no such problems.

I am not familiar with NetworkManager. Is this something related to its removal? Or something in the patches might have caused the problem. Any suggestion where to start to debug?

Thanks in advance.
David

[TrevorH]

Do you have ONBOOT=yes in the /etc/sysconfig/network-scripts/ifcfg-eno49 file?

[wdli]

yes I do have that.

One thing I am guessing is that the removal of NM might have caused it. Maybe the interface was under NM control but now it's gone. Would this cause confusion during reboot?

[wdli]

I kind of solved this problem: I reinstalled NetworkManager and reboot works with IP address coming back to the interface.

But still I don't know the detailed root cause. Was this because the interface was under NM control and removing NM caused some confusion to the startup scripts? Would it likely that the startup scripts think it's NM's responsibility to bring up the interface even when it's non-existence?

[TrevorH]

Post the contents of the relevant ifcfg file

[gerald_clark]

If you disable/uninstall NetworkManager service, you need to enable and start the network service instead.