[ncolug] Re: vm
- From: "Rob Gibson" <nosbig@xxxxxxxxx>
- To: ncolug@xxxxxxxxxxxxx
- Date: Fri, 23 Nov 2007 11:24:23 -0500
The hypervisors typically create a Linux process to contain the
instance of the operating system kernel, whether that be Linux,
Windows XP or Windows ME.
What you really ought to do for servers is to get an interface card
for the UPS that supports SNMP. APC makes a ton of them. Then, your
virtual machines can do the right thing on their own even before the
host gets involved. Once the host feels the need to come down, it can
signal the processes containing the kernels to shut down.
Rob
On Nov 23, 2007 10:47 AM, larry <larry@xxxxxxxxxxxx> wrote:
> Can you back up your statement that an instance of Windows NT appears to
> the hypervisor to be a Linux app? Even id the hypervisor is a Windows
> application? Doesn't make sense to me.
>
> I stand by my statement that a SIGHUP is meaningless to any OS other
> than Linux.
>
>
> Chuck Stickelman wrote:
> > Writing a program that sends a SIGHUP to another process upon a specific
> > event id trivial. I'm not programmer butr I could do it in a BASAH script.
> >
> > >From trhe hypervisor's point of view they are Linux apps and therefore
> > >should behaive as such. Linux apps should behaive properly when they
> > >catch a signal. The shell-script that was posted earlier effectively does
> > >just that.
> >
> > The good would be that the guest OS would initiate a shutdown upon seeing
> > the SIGHUP from the Hypervisor... Sems pretty useful to me...
> >
> > Chuck
> >
> >
> > -----Original Message-----
> > From: "larry" <larry@xxxxxxxxxxxx>
> > To: "ncolug@xxxxxxxxxxxxx" <ncolug@xxxxxxxxxxxxx>
> > Sent: 11/23/2007 9:40 AM
> > Subject: [ncolug] Re: vm
> >
> > I am quite sure I am missing things, the point of your message being
> > only one of many... that is why I am running this by you all.
> >
> > 1.) no one has verified that any hypervisor is ABLE to send a SIGHUP in
> > response to an external event
> > 2.) they are *not* "after all, Linux apps" - they are instances of
> > operating systems
> > 3.) if it did send it, what good would that do for a Windows guest? Or a
> > MAC OS guest?
> >
> >
> > Chuck Stickelman wrote:
> >
> >> Larry, I think you mised the point of my prevoius message...
> >>
> >> The guests *should* shut down cleanly when the Hypervisor sends them a
> >> SIGHUP. (...regardless of why the Hypervisor sends the signal...) Sending
> >> a SIGHUP to the guest VM *should* be the same as choosing to shut it down
> >> from inside the VM...
> >>
> >> They are, afterall, just Linux apps...
> >>
> >> Of couse the UPS doesn't send the SIGHUP that's the job of the Linux
> >> Hypervisor. Which is the best choice for monitoring the UPS... Though
> >> some UPS monitoring applications have LAN awareness and can push the UPS
> >> status out to multiple systems - both Physical and Virtual...
> >>
> >> Chuck
> >>
> >>
> >> -----Original Message-----
> >> From: "larry" <larry@xxxxxxxxxxxx>
> >> To: "ncolug@xxxxxxxxxxxxx" <ncolug@xxxxxxxxxxxxx>
> >> Sent: 11/22/2007 10:32 PM
> >> Subject: [ncolug] Re: vm
> >>
> >> No, the guests do NOT "shut down cleanly" just because you stopped or
> >> shut down the hypervisor.
> >>
> >> You want to talk about "standards" in regard to UPS signaling
> >> behaviour?! Which of the dozen or so standards would you like to discuss?
> >>
> >> Mike wrote:
> >>
> >>
> >>> Chuck Stickelman wrote:
> >>>
> >>>
> >>>> So what I hear you say is:
> >>>> Hook the UPS to the physical machine
> >>>> Have the host OS monitor the UPS's state
> >>>> When the UPS signals the host it sends a SIGHUP to the Virtual Machines
> >>>> The VMs should then interpret the SIGHUP as a Shutdown command
> >>>>
> >>>> Is that what you had in mnd?
> >>>>
> >>>> Does anyone know if that's how it works?
> >>>>
> >>>> Chuck
> >>>>
> >>>>
> >>> Yes.
> >>>
> >>> The signal may depend on the VM design though. I would hope they have
> >>> used enough sense to honor some standard.
> >>>
> >>> This really is a near trivial problem. The guests shutdown cleanly
> >>> during a normal shutdown, yes? Why should a shutdown instituted by
> >>> UPS software or even admin written (monitoring) scripts be any different?
> >>>
> >>> Mike
> >>>
> >>> To unsubscribe send to ncolug-request@xxxxxxxxxxxxx with 'unsubscribe'
> >>> in the Subject field.
> >>>
> >>>
> >>>
> >>>
> >>
> >>
> >
> >
>
> --
> "Perception is strong and sight weak. In strategy it is
> important to see distant things as if they were close and
> to take a distanced view of close things."
> Miyamoto Musashi (1584-1645)
>
>
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> Subject field.
>
>
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