On 05/01/2014 09:09 AM, Les Mikesell wrote: > 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). > I feel for you then. I guess we have been lucky in the 6 or 7 hardware platforms we have used that the nics ( minimum 3, usually 4 or more ) have always stayed the same names in the same order. -- Stephen Clark *NetWolves Managed Services, LLC.* Director of Technology Phone: 813-579-3200 Fax: 813-882-0209 Email: steve.clark at netwolves.com http://www.netwolves.com