Archive for the ‘Admin’ Category
Occasionally, for the purposes of internal testing or continuity, it’s desirable to bring up a server with a duplicate MAC address. It’s a safe enough manoeuvre (so long as these machines operate on different wires) for the brief periods in which I require it but when this scenario involves the installation of a new server via our installroot PXE service, things are trickier.
Our PXE server is configured automagically by spanning map and, effectively, keyed on MAC, so it’s unlikely to present the correct configuration (reliably) when the new host differs from the old one in some way.
The workaround is to override the PXE configuration on the *existing* server (on the basis that you weren’t planning on reinstalling it, anyway, were you?):
!pxeclient.platforms mADD(new_plat_name) /* e.g. sl6_64 */ /* And, if you need to add or remove serial console support: */ !pxeclient.serial_port mSET(ttyS0) /* or () */
dhclient component is aware of subnet differences and will ensure your machine receives the correct profile for installation (though, to prevent future confusion, remove this as soon as the installer has done its work!).
Nagios is an extremely useful tool, until it isn’t. Which is to say, it’s nothing but a hindrance to have nagios continue to bombard you with IMs and emails when you’re already working on the problem.
Surely you can just acknowledge the fault and shut it up…?
Well, sometimes, but it is hardly convenient to break out a Firefox session when you’re attached to a serial console with your lovely secure-shell-enabled phone. And even if you are on a DICE machine it’s a bit of a pain to have to navigate the slightly clunky Nagios UI to find the host and service you wish to silence.
I started with a dumb bash script. Read the rest of this entry »