Stupid Newbee Questions...

DISCUSSION Stuart Sheldon 3 participants 6 messages Apr 22, 2008 – Apr 23, 2008 KVM

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Stuart Sheldon

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2008-04-22 23:50 UTC #0 lore raw

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I've looked around but can't seem to find these answers.

I'm using KVM to run multiple servers on the same hardware, but it seems that most of the documentation written is for desktop use.

I'm currently running KVM-66 on a 2.6.24.4 kernel and using the KVM provided modules. This is sitting on a Debian Lenny install with Intel hardware.

Here are my questions:

1) Is there a way to give one virtual host priority over another? Would I just add -cpu 2 on the host I want to give priority?

2) When I started writing the management scripts to start and stop the guests from the command line, I was using KVM-63 which allowed me to send a "system_powerdown" to the console, this would send a PWR to the guest's acpid that would bring the guest down gracefully. This stopped working in kvm-64 and is still not working in kvm-66. Is there a better way to do this? How can the host bring down a guest without messing with it's open programs?

3) Are there any statistics available from to the host os that can be monitored, such as something in /sys or /proc?

Thanks in advance to all that answer!

Stu

- --
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Amit Shah

2008-04-23 05:54 UTC #1 lore raw

Quoted 5 lines · * On Wednesday 23 Apr 2008 05:20:03 Stuart Sheldon wrote:

I've looked around but can't seem to find these answers.
I'm using KVM to run multiple servers on the same hardware, but it seems that most of the documentation written is for desktop use.

Quoted 8 lines

I'm currently running KVM-66 on a 2.6.24.4 kernel and using the KVM provided modules. This is sitting on a Debian Lenny install with Intel hardware.
Here are my questions:
1) Is there a way to give one virtual host priority over another? Would I just add -cpu 2 on the host I want to give priority?

Renicing the guest you want to give more priority to is a straightforward way of boosting the priority. It's easy to imagine that, since each guest is just a process on the host.

Quoted 7 lines

2) When I started writing the management scripts to start and stop the guests from the command line, I was using KVM-63 which allowed me to send a "system_powerdown" to the console, this would send a PWR to the guest's acpid that would bring the guest down gracefully. This stopped working in kvm-64 and is still not working in kvm-66. Is there a better way to do this? How can the host bring down a guest without messing with it's open programs?

I've no clue about this one; will let someone else answer it.

Quoted 2 lines

3) Are there any statistics available from to the host os that can be monitored, such as something in /sys or /proc?

Can you mention what kinds of stats you're looking for? Since each guest is a normal process, a lot of information can be already examined by ps, top and /proc/<pid>/...

There also is the kvm_stat that comes with the kvm-userspace which lets you monitor guest exits into the host. Those are mainly for debugging purposes though.

Avi Kivity

2008-04-23 06:24 UTC #2 lore raw

In reply to Stuart Sheldon

Quoted 8 lines · Stuart Sheldon

2) When I started writing the management scripts to start and stop the guests from the command line, I was using KVM-63 which allowed me to send a "system_powerdown" to the console, this would send a PWR to the guest's acpid that would bring the guest down gracefully. This stopped working in kvm-64 and is still not working in kvm-66. Is there a better way to do this? How can the host bring down a guest without messing with it's open programs?

This is not a question, it's a bug report. It's a clear regression that needs to be fixed, not worked around.

Please send timely reports of such issues when you encounter them.

Signature · 8 lines

Any sufficiently difficult bug is indistinguishable from a feature.


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Avi Kivity

2008-04-23 10:07 UTC #3 lore raw

Quoted 10 lines · Avi Kivity

Quoted 8 lines · Stuart Sheldon
2) When I started writing the management scripts to start and stop the guests from the command line, I was using KVM-63 which allowed me to send a "system_powerdown" to the console, this would send a PWR to the guest's acpid that would bring the guest down gracefully. This stopped working in kvm-64 and is still not working in kvm-66. Is there a better way to do this? How can the host bring down a guest without messing with it's open programs?

Quoted 5 lines

This is not a question, it's a bug report. It's a clear regression that needs to be fixed, not worked around.
Please send timely reports of such issues when you encounter them.

This was caused by

commit 6bb0805aeabd5c6ef5408f57c7da5ca6385dd0f5

Author: Dor Laor <[email protected]>
Date:   Thu Mar 13 00:11:41 2008 +0200

kvm: qemu: fix sci irq set when acpi timer about to wrap

The acpi timer should generate sci irq when enabled and when bit 23 of the timer counter toogles.

Fixes time reading by the performance counter api of windows guest.

I'm reverting it for kvm-68.

Signature · 8 lines

Do not meddle in the internals of kernels, for they are subtle and quick to panic.


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Stuart Sheldon

author

2008-04-23 19:23 UTC #4 lore raw

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Thanks to both of you for answering my questions. And thank you Avi for fixing the bug. I did not report it because of some of the conversation I saw in the mailing list regarding that feature, and thought it might have been removed.

Thanks again...

Stu

Quoted 25 lines · Avi Kivity

Quoted 10 lines · Avi Kivity
Quoted 8 lines · Stuart Sheldon
2) When I started writing the management scripts to start and stop the guests from the command line, I was using KVM-63 which allowed me to send a "system_powerdown" to the console, this would send a PWR to the guest's acpid that would bring the guest down gracefully. This stopped working in kvm-64 and is still not working in kvm-66. Is there a better way to do this? How can the host bring down a guest without messing with it's open programs?
Quoted 5 lines
This is not a question, it's a bug report. It's a clear regression that needs to be fixed, not worked around.
Please send timely reports of such issues when you encounter them.
This was caused by
commit 6bb0805aeabd5c6ef5408f57c7da5ca6385dd0f5
Author: Dor Laor <[email protected]>
Date:   Thu Mar 13 00:11:41 2008 +0200
kvm: qemu: fix sci irq set when acpi timer about to wrap

Quoted 9 lines

The acpi timer should generate sci irq when enabled and when bit 23 of the timer counter toogles.
Fixes time reading by the performance counter api of windows guest.
I'm reverting it for kvm-68.

- --
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Avi Kivity

2008-04-23 21:15 UTC #5 lore raw

Quoted 4 lines · Stuart Sheldon

Thanks to both of you for answering my questions. And thank you Avi for fixing the bug. I did not report it because of some of the conversation I saw in the mailing list regarding that feature, and thought it might have been removed.

If you see us removing a feature you need, let us know. We might reconsider it.

It's better to waste our time by asking "stupid newbee questions" than wasting our time (and other users' time) by not reporting bugs, or letting us remove useful features.

[Having said all this lofty stuff, our bug counts are piling up, with no light at the end of the tunnel...]

Signature · 9 lines

Do not meddle in the internals of kernels, for they are subtle and quick 
to panic.


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