Karanbir Singh wrote:
A killer on remote machines can be when the new kernel detects your NIC cards in a different order and either skips initialization or assigns the wrong IP's.
isnt that why you use hwaddr in your network scripts ?
That's even worse. All of my remote machines have swappable disks and almost all of them are cloned from a few masters, shipped, and swapped into the destination machine with the IP address set on a temporary box.
This is your site policy, and is not necessary how everyone runs their machines. I, for one, take it that each drive that is added to a machine is going to be empty - its trivial to remaster a machine on the fly with tools like cobbler+koan and use puppet to manage the machine, Capistrano to manage app rollout.
I'm not familiar with those tools, but I assume they require a certain amount of nearby infrastructure which would be extra trouble to duplicate and maintain in all our remote locations. And it doesn't cost any more to ship a disk already loaded than empty.
The concern you raised was about network interfaces not coming up in a predictable manner when people move from centos-4 to centos-5, the answer to which is, use hwaddr's in your network scripts.
The concern it more general - more about unpredictable differences. Having seen a difference in what the hwaddr setting does even within a version, I wouldn't count on it to work across versions without testing it first.