Re: [Xen-users] resetting lost root password on a xen guest

[Darren Jacobs <dhj@xxxxxxxxxxxxxxx>]

That worked.  Thanks Steve.  It was just too straight forward for me  
to think of :')


On 30-Oct-07, at 11:35 AM, Steven Timm wrote:

> Darren--can you temporarily stop the xen guest and mount
> its root FS from dom0? if so, then just zero out the root passwd
> and shadow entry from there, unmount the client rootfs, being
> sure to fsck it afterwards, then start up the client again.
>
> Steve
>
>
> On Tue, 30 Oct 2007, Darren Jacobs wrote:
>
> > Hi All,
> >
> > I need to get into a xenguest running linux for which the root  
> > password has been lost.  I'm running xen 3.0.3 under RH 5.
> > I'm trying to figure out how to get pygrub for this guest to load  
> > up the typical "init=/bin/sh" to get the console to come up at the  
> > command line prompt so I can reset the root password.
> > Trolling though google I've see suggestions to add args = 'init=/ 
> > bin/sh' or opts = 'init=/bin/sh' to the guest configuration file.   
> > None of them appeared to have worked.  If I do a 'xen create echo11  
> > -n' after making any of the above file mods I see that the args  
> > were not modified:
> > --
> > (vm
> >  (name echo11)
> >  (memory 500)
> >  (on_reboot restart)
> >  (on_crash restart)
> >  (vcpus 1)
> >  (uuid cb855323-2867-b84a-d766-32a39d252bb7)
> >  (bootloader /usr/bin/pygrub)
> >  (image
> >      (linux
> >          (ramdisk /var/lib/xen/initrd.kIQYUw)
> >          (kernel /var/lib/xen/vmlinuz.Xwl81-)
> >          (args 'ro root=/dev/VolGroup00/LogVol00')
> >      )
> >  )
> >  (device
> >      (tap (uname tap:aio:/var/lib/xen/images/echo11) (dev xvda)  
> > (mode w))
> >  )
> >  (device (vif (bridge xenbr0) (mac 00:16:3e:69:69:90)))
> > --
> >
> > So I tried to bring the guest up manually from dom0 with " pygrub / 
> > var/lib/xen/images/echo11.dsk".  When the menu comes up I edit the  
> > kernel line directly and insert "init=/bin/sh".  You can see below  
> > that the init statement was indeed read:
> > --
> > [root@dom0 xen]# pygrub /var/lib/xen/images/echo11
> > Going to boot Fedora (2.6.20-2925.13.fc7xen)
> > kernel: /vmlinuz-2.6.20-2925.13.fc7xen
> > initrd: /initrd-2.6.20-2925.13.fc7xen.img
> > linux (kernel /var/lib/xen/vmlinuz.pBqWti)(ramdisk /var/lib/xen/ 
> > initrd.9IdU7X)(args 'ro root=/dev/VolGroup00/LogVol00 init=/bin/ 
> > bash')
> > [root@dom0 xen]#
> > --
> >
> > However the guest did not start up :'(  Its starts just fine if I  
> > issue a "xm create echo11".  Any suggestions on where to look from  
> > here?
> --
> ------------------------------------------------------------------
> Steven C. Timm, Ph.D  (630) 840-8525
> timm@xxxxxxxx  http://home.fnal.gov/~timm/
> Fermilab Computing Division, Scientific Computing Facilities,
> Grid Facilities Department, FermiGrid Services Group, Assistant  
> Group Leader.

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