CentOS 7 + SystemD + Predictable Network Interface Names

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Hi list, I’m trying CentOS7 and using systemD. I’ve noticed that interfaces name does not have anymore eth0,eth1, ethN but a different name.

What do you think about predictable network if name assigned by systemd?

8 thoughts on - CentOS 7 + SystemD + Predictable Network Interface Names

  • For what its worth, there was a change in device naming in CentOS 6
    (going from eth0 -> em1, for example) which affected a subset of hardware out there (We saw it on Dell hardware, mostly). We had already managed to deal with the fact tha ‘eth0’ is no longer guarenteed (in scripts, usually by looking in /sys/class/net/), so dealing with non-eth0-naming wasn’t a huge surprise, however, the way devices are named changed. For what it’s worth, I am not thrilled with the incredibly complex names but I understand their utility.

    There are a couple of ways to disable it listed here:

  • No experience yet, but it will be very valuable to us if, in fact, the names really are predictable in terms of matching up with the physical connections on similar hardware. Moving an installed disk to a different chassis or restoring a backup on a different box can be painful on systems with a large number of nics that are named in essentially random order like the older systems. So, I think it is a great idea and should have been done that way from the start, but I’m not convinced yet that it will really work on most hardware.

  • eth0 was never guaranteed to be the ‘right’ interface – or even to exist in some circumstances with udev naming. If scripts using fixed names ever worked it was mostly a matter of luck.

  • Alessandro Baggi wrote:
    does not have anymore eth0,eth1, ethN but a different name.

    They’re doing it as emx, where x=[1…], except where it wants old Sun-style pxdx… which I hate. I can live with emx, if I have to.

    People who can’t count from 0….

    Folks here heard about the actual fork of systemd called uselessd? And they want it to do actual work, but not much of what systemd does…?

    mark “saw it on slashdot”

  • What hardware is that on? The only multi-NIC box I’ve installed so far is an HP with eno1 through eno4 plus ens2f0, ens2f1, ens3f0, and ens3f1. A similar remote box has eno1-eno4 plus ensf0 and ensf1. I’m assuming the nics there are installed in a different slot….