mjhjmtu

I'm renaming network interfaces by modifying the files in /etc/sysconfig/network-scripts.

• eth0 -> nic0


• eth1 -> nic1

The content of the network scripts looks like this, after modification:

# cat /etc/sysconfig/network-scripts/ifcfg-nic0
DEVICE=nic0
BOOTPROTO=static
ONBOOT=yes
HWADDR=xx:xx:xx:xx:xx:xx
USERCTL=no
IPV6INIT=no
MASTER=bond0
SLAVE=yes

A reboot activates the new config. But how do I activate this configuration without rebooting?

A systemctl restart network doesn't do the trick.

I can shut down one interface by its old name (ifdown eth0) but ifup results in below message no matter if the old or new name was provided:

ERROR : [/etc/sysconfig/network-scripts/ifup-eth] Device nic0 does not seem to be present, delaying initialization.

/etc/init.d/network status shows this output:

Configured devices:
lo bond0 nic0 nic1
Currently active devices:
lo eth0 eth1 bond0

Both, ifconfig and ip a show the old interface names.

You can rename the device using the ip command:

/sbin/ip link set eth1 down
/sbin/ip link set eth1 name eth123
/sbin/ip link set eth123 up

Edit:

I am leaving the below for the sake of completeness and posterity (and for informational purposes,) but I have confirmed swill's comment and Marco Macuzzo's answer that simply changing the name and device of the interface /etc/sysconfig/network-scripts/ifcfg-eth0 (and renaming the file) will cause the device to be named correctly as long as the hwaddr= field is included in the configuration file. I recommend using this method instead after the referenced update.

You may also want to make sure that you configure a udev rule, so that this will work on the next reboot too. The path for udev moved in CentOS 7 to /usr/lib/udev/rules.d/60-net.rules but you are still able to manage it the same way. If you added "net.ifnames=0 biosdevname=0" to your kernel boot string to return to the old naming scheme for your nics, you can remove

ACTION=="add", SUBSYSTEM=="net", DRIVERS=="?*", ATTRtype=="1", PROGRAM="/lib/udev/rename_device", RESULT=="?*", NAME="$result"

And replace it with

ACTION=="add", SUBSYSTEM=="net", DRIVERS=="?*", ATTRaddress=="00:50:56:8e:3f:a7", NAME="eth123"

You need one entry per nic. Be sure to use the correct MAC address and update the NAME field. If you did not use "net.ifnames=0 biosdevname=0", be careful as there could be unintended consequences.

Actually, the best answer I believe is the combination of the two answers already posted. In order to change the device name without restarting network services, use the ip link commands suggested by James Shewey (ip link set <old_device_name>; name <new_device_name>).

To make the changes survive a reboot in Red Hat Linux, modify the relevant file in /etc/sysconfig/network-scripts/. Rename the file ifcfg_<old_device_name> to ifcfg_<new_device_name> and change the DEVICE variable inside to <new_device_name>. Also, make sure the HWADDR variable is set and is correct. There is no need to touch udev rules, since 60-net.rules is actually there to read the ifcfg configuration files in /etc/sysconfig/network-scripts.

The Answer given by @James Shewey seems to be the right way to do it.

If you want to just work with the config files in /etc/sysconfig/network-scripts and then trigger a reload, unloading and loading the kernel module as mentioned by @Tom Hunt in the comments also works:

service network stop
modprobe -r igb
modprobe igb
service network start

If you access the machine remotely, make sure you run all commands in a nohup or you will lock yourself out:

nohup sh -c "service network stop && modprobe -r igb && modprobe igb ; service network start"

The driver to reload of course depends on your interface.

To restore the old naming convention, you need to edit the /etc/default/grub file and add the following

net.ifnames=0 biosdevname=0 

at the end of the GRUB_CMDLINE_LINUX variable

ip link set ens33 down
ip link set ens33 name eth0
ip link set eth0 up

mv /etc/sysconfig/network-scripts/ifcfg-ens33,eth0

sed -ire "s/NAME="ens33"/NAME="eth0"/" /etc/sysconfig/network-scripts/ifcfg-eth0

sed -ire "s/DEVICE="ens33"/NAME="eth0"/" /etc/sysconfig/network-scripts/ifcfg-eth0

MAC=$(cat /sys/class/net/eth0/address)

echo -n 'HWADDR="'$MAC" >> /etc/sysconfig/network-scripts/ifcfg-eth0