On Thu, May 1, 2014 at 5:54 AM, Steve Clark <sclark at netwolves.com> wrote: > On 04/30/2014 02:41 PM, Les Mikesell wrote: > > On Wed, Apr 30, 2014 at 1:28 PM, Steve Clark <sclark at netwolves.com> wrote: > > So, have you ever had to deal with a CentOS box and multiple NICs. > Especially one where you've cloned it or moved a disk to a new > chassis? Apparently there is just not a good way to identify > interfaces. > > Yep, do it all the time - first two thing I do are: > rm -f /etc/udev/rules.d/70-persistent-net.rules > rm -r /etc/sysconfig/network-scripts/ifcfg-eth* > and then reboot. > > So, now you've got 6 NICs connected to 6 different switches. Which > name is which? This is a really fun exercise when the box is remote > and you are trying to tell someone used to configuring windows systems > how to get it to a point where you can ssh in. > > I guess I am confused, you haven't ever worked with the hardware you are > installing the cloned > drive in? If that is true then I guess you have a problem. > "Working with it" doesn't matter. And network manager or not doesn't matter. Interfaces get named in a random order unless it is a Dell with the netbios naming scheme and probably then only for the motherboard NICs. Our servers generally have on-board Broadcomm and Intel cards and the names within a set may stay ordered, but the cards and motherboards will flip randomly if there are not already matching items with the correct MAC addresses in the udev rulss file (in 6.x, in 5.x having a matching MAC in the ifcfg-eth? file was enough to rename the device to match). This is just a response to your comment about windows names being difficult to know, (and a long-standing problem on its own) and doesn't relate much to the NetworkManager discussion. If you only have one (or maybe even a pair on the motherboard or a single card) you might always see the same ordering - if so consider yourself lucky because that is not the general case. We usually have to run through a drill like 'ip link ls' to get a list of interface names, then iterate through them with 'ifconfig up' and use ethtool to see which has link up, connecting one at a time. So, in my opinion, there are problems with the old system that need to be fixed, but they aren't the things that networkmanager does. A way to restore a backup to an identical machine and have the same NICs in the same positions get the old configurations would be nice. Or at least to know the names of the NICs in the same positions. (And if you go back to CentOS3 they did - detection was single threaded back then and would always probe in the same order). -- Les Mikesell lesmikesell at gmail.com