zenhost is a Xen dom0 (hosted by bddebian) which is hosting several domUs (see the table on public hurd boxen for a list).

listing running domUs

$ sudo xm list

$ sudo xm top

handling running domUs

Forcefully killing a domU (that has crashed or is busy-looping, etc.):

$ sudo xm destroy [domU]

As for (re-)starting a domU, read below in domU consoles.

Using xm shutdown [domU] to gracefully shut down a running domU does not yet work -- this is not yet implemented in the Xen port of GNU Mach (open issue xen).

domU consoles

To avoid any complications with people trying to use the same console at the same time, please use this command for attaching to a domU's console (this command line will also start the domU in case that it isn't running already):

$ host=[domU] && sudo screen -DRRS console-$host sh -c "xm console $host || xm create -c $host"

Otherwise, if one attaches to the same console twice, the second instance will in fact forward input to the domU (possibly infering with what the person is doing on the first instance), but the output won't be sent back to the second instance.

After having typed this once, Bash's reverse-search-history (C-r), followed by typing in host=flubber, for example, will be enough to get access to that machine's console.

/!\ TODO: How does one get the environment variables COLUMNS and LINES set properly when using xm console? According to Samuel, you don't, the xen console doesn't have the notion of terminal size. This is relevant for everything using (n)curses -- for interactive console applications. Using export COLUMNS=143 LINES=44 does work, but is a manual process.

Posted 2009-10-05 14:37:29 CEST Tags:

Installation of new machines