CentOS 6.2 no longer includes NetworkManager by default

Distro Discussion & Help
1

FYI-

CentOS 6.2 no longer includes NetworkManager by default. It appears that the Distro attempts to call NetworkManager during installation, but it is not there. As a result, no network configuration is done during Distro installation, and the default of DHCP is simply configured.

Further, CentOS 6.2 no longer includes system-config-network. However you can install it by typing:

yum install system-config-network-tui

and then you can invoke it by typing:

system-config-network.

2

I dont see anywhere that we call Network Manager with a install. I think you are confused and I just tried a install with static and it set it all just fine.

3

I did a bunch of research on the differences between CentOS 5.x and CentOS 6.x this weekend.

What I discovered was that RedHat has changed the text install of anaconda. The text install has minimum capabilities. I think this changes the way a text based install can be done. In my case the system no longer asks for a hostname so this needs to be configured manually.

These post seemed to explaine some of what has happened.

http://www.standalone-sysadmin.com/blog/2011/08/centos-6-angers-me-again/

https://access.redhat.com/knowledge/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Installation_Guide/ch-guimode-x86.html#id981573

4

Yeah, I was confused, but there still is a potential issue. Centos 6.2 no longer scans for and automatically configures NEW NIC cards during boot.

So, if you do a fresh install of the Distro with Centos 6.2, and then you replace your Network card or migrate to a new machine or clone a VM, the new NIC card won’t be detected and configured as ETH0. Instead, it’ll be detected as ETH1 (or whatever is next in the numerical order) and won’t be configured at all.

The system will have no network connectivity until you manually create the ifcfg-ethxx file.

There is a workaround and I’m working on writing something up for it.

5

Actually, you have to duplicate your ifcfg-ethX file and remove the HWADDR line, and then it will work.

But, under CentOS 5.x, this wasn’t necessary. Upon boot, the OS detected a new NIC card and automatically configured it for DHCP. Also, CentOS 5.x included a utility to re-configure the NIC, but that utility is not installed by default on 6.x.

6

So, if you do a fresh install of the Distro with Centos 6.2, and then you replace your Network card or migrate to a new machine or clone a VM, the new NIC card won’t be detected and configured as ETH0. Instead, it’ll be detected as ETH1 (or whatever is next in the numerical order) and won’t be configured at all.

This goes back to centos 4 and is actually a “feature” the fix is easier than you think.

Don’t specify HWADDR in your ifcfg-ethX file.

7

See this: http://www.syn-ack.org/centos-linux/renumber-ethernet-interface-eth0/#comment-40298
It works very well (and fast) for me.