[CentOS] A question about 7

[Les Mikesell]

On Wed, Jan 15, 2014 at 6:05 AM, Steve Clark <sclark at netwolves.com> wrote:
> On 01/14/2014 08:34 PM, Les Mikesell wrote:
>
> On Tue, Jan 14, 2014 at 7:17 PM, Warren Young <warren at etr-usa.com> wrote:
>
> I don't know about "less consistent", but I always considered it a
> feature in Linux vs the BSDs or big iron Unix that I could always count
> on the first network interface being "eth0".
>
> What does 'first' mean?  And the same one isn't consistently first.
>
> I get that network interfaces can move around on you, but I thought that
> was why they started putting the MAC address in the ifcfg-eth? scripts.
> What problem did that not solve, that we had to switch to this new system?
>
> The problem is when you clone a disk and ship it to a location with
> 'hands-on' support that doesn't know linux to install in a new chassis
> that will arrive there at the same time.   Somehow you have to get
> someone to put the 4 network cables in the right NICs before anything
> can connect.   With things tied to MAC addresses that you don't know
> ahead of time, nothing will work.
>
> Now I have to remember which *PCI slot* my Ethernet card is in when I
> run "ifconfig" unless I want to dig through the full listing.
>
> Yes, but that's something you _can_ know.
>
> How can you know it? And if you know which port is which why isn't in the
> instruction
> with the drive so the people on site know which port is which?

If you insert the card yourself, you obviously know the slot.  And you
can tell the position from the back just by looking at it.   But
Centos6 will detect in random order, so knowing the name on one box
doesn't help with another.   We have to go through contortions
plugging on cable in at a time, doing an 'ifconfig up' and checking
which interface shows link up.   And the people  doing that part wish
we used more windows instead of Linux.

-- 
  Les Mikesell
     lesmikesell at gmail.com