Manage XEND

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Managing Xen Virtual Machines

Xend can only be managed on dom0, as it has only exlusive access to the hardware. As a result, any temperature or SMART/Disk Monitoring must be done here also.

The basic commands are:

xm list
xm top

To get a list of all the XEND control options type:

xm


To RESTART XEND when it crashed etc.

This is extreme - and caused the Virtual Machine in question to remain "dying".

/etc/init.d/xend restart  //didnt work
//do this ->
/etc/init.d/xend stop
killall xenstored xenconsoled
rm -rf /var/lib/xenstored/*
/etc/init.d/xend start
netstat -ltnp  //make sure there is nothing on ports 8000, 8001, 8002, or 8005
kill any above processes if there are and ->
/etc/init.d/xend start //this will get xend up and running. The virtual machines may need taking care of

XEN LIST TOP Codes

xm top

http://www.die.net/doc/linux/man/man1/xm.1.html

Limit CPU of a VM

So the need arised to limit the CPU usage by a particular VM which was chewing up 100% CPU of 1 core by running a heavy computational program for 10+ days.

thunder:~# xm sched-credit -d vm05-name
{'cap': 0, 'weight': 256}
thunder:~# xm sched-credit -d vm05-name -c 20   #20 is 20% of 1 physical cpu. Default is 0.
thunder:~# xm sched-credit -d vm05-name
{'cap': 20, 'weight': 256}

xm top
#  Domain-0 -----r     	   410753    0.4 
#vm05-name ------                 855770   19.9 
(previously the vm was using 100)

http://wiki.xensource.com/xenwiki/CreditScheduler Simple :) Munin graphs look a lot better now.



-- More info at http://lists.xensource.com/archives/html/xen-tools/2005-09/msg00011.html
http://lists.xensource.com/archives/html/xen-users/2006-05/msg00397.html

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