Cheat sheet

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Revision as of 23:10, 7 July 2010 by Will (talk | contribs) (So You Wanna Administrate prgmr.com)

So You Wanna Administrate prgmr.com

Here's some handy commands for reference.

You can see a list of our servers here

Need to know if a dom0 has sufficient RAM for a new user? Use xm info.

There is usually enough disk space, but if you need to find out anyway, you can use lvdisplay or vgdisplay

swapip.pl will let you grab a new IP for a user. Make sure they're not configured with an IP already - this doesn't change anything except what Freeside thinks their IP is.

Lifeboat uses pmshell. The other conserver uses /usr/bin/console.

Need to upgrade a user? Modify their RAM in their /etc/xen/username configuration file, then add the disk space with lvextend.

If the dom0 is hydra or older, you need to add a new partition with their new space using lvcreate -C y -L $DISK_in_ -n ${LVNAME} ${DG}

e.g. lvcreate -C y -L 100M -n guests username_2nd
Don't forget to add their new disk to the config file.

Need to update rDNS?

nsupdate does this; you can find the key in /usr/local/etc. There's a script to handle this dish:~/will/rdnsupdate

Here's how to move a user from one dom0 to another.

First, domucreate -f them on the new server.
You can find the relevant details in their /etc/xen config. Distro doesn't matter, because you're going to overwrite it anyway.
Next, /sbin/kpartx -dv their disk because the partitioning might be wrong.
Zeroing out the disk is okay if you really want to.
Now, copy over the old disk to the new server with ssh oldserver "dd if=/dev/mapper/guests-username bs=512k (or something)" | dd of=/dev/mapper/guests-username bs=512k
if = inputfile
of = output file
bs = chunk size, relevant for transfer only. Larger sizes may speed up the transfer.
Finish up with kpartx -av
Make sure it works by doing something like fsck.ext3 -n or something non-writing on the filesystem.