CentOS 6/7

[Brian Cluff]

On 12/4/18 12:40 PM, Snyder, Alexander J wrote:
> Does anyone know why networking devices aren't eth0/1/2/3 but are now 
> ens0f0/enp0d0.

Those are the new "Predictable Network Interface Names" based on where 
they are physically plugged into the system.
You can read all about them here:
https://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames/
In a nut shell they make sure that you device names don't ever change 
which is really annoying when you have a server is hosted out of state 
and can't get your hands on it to fix all your scripts that use eth0 as 
your internet facing interface when it suddenly switches places with 
eth1 or gets bumped to eth3 for any number of reasons.
The new names are a little jarring at first, but if you allow yourself 
to get used to them then you will be able to tell someone, without any 
doubt, based on the devices name which exact device needs to be swapped 
out when it fails, and the replacement device will be given the same 
name, as long as it's plugged into the same place)

> Also getting into single user mode now is (IMHO) unnecessarily 
> complicated (typing 'single' versus now 'init=/sysroot/bin/bash').

init=/sysroot/bin/bash has always worked and is my preferred way of 
getting into a system without running anything else.  That line simply 
tells grub to bypass starting the system's init system which is systemd 
on the newer systems and to instead run bash as linux's init.

If you are looking to get into a true single user mode you will probably 
want to instead use one of the following lines where you were previously 
using init=/sysroot/bin/bash:

systemd.unit=rescue.target (can be shortened to systemd.unit=rescue)
or
systemd.unit=emergency.target (can be shortened to systemd.unit=emergency)

The emergency target is the most minimal of the 2.

Brian Cluff