7:21 a.m.
I am looking at the shutdown method, but if the guest system is a desktop
system, like for example ubuntu, it just has the effect to show a box
prompting the user for a shutdown/reboot/ and such.
I could enter the guest and change this default behaviour and it actually
works..but I'd like for a way to send a shutdown command without doing so.
Is it possible?
9:12 a.m.
On 03/29/2014 06:21 AM, Pasquale Dir wrote:
I am looking at the shutdown method, but if the guest system is a
desktop
system, like for example ubuntu, it just has the effect to show a box
prompting the user for a shutdown/reboot/ and such.
I could enter the guest and change this default behaviour and it actually
works..but I'd like for a way to send a shutdown command without doing so.
Is it possible?
Guest shutdown is ALWAYS a cooperative action. It sounds like your
guest defaults to an interactive shutdown when an ACPI shutdown request
is received. You can install qemu-guest-agent in your guest and send
shutdown via the agent instead of via ACPI - that may be a bit more
responsive at doing an immediate shutdown. But beyond that, no, there
is no way to guarantee a graceful guest shutdown without guest
cooperation. If you must stop a guest, and shutdown is taking too long
because the guest is not cooperating, then use the 'virsh destroy' command.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
3:47 a.m.
Yes, you are right.
Listen, as the documentation is not very exaustive, can you explain briefly
to me how a guest agent works?
After installing it via the apt-get on the hypervisor (I am using ubuntu as
host system) how can I create a script which would do this?
That is waiting for an acpi signal and actually shut down the guest.
And what other operation can you actually do with a guest agent? I would be
interested in getting the current amount of memory the guest is using
too...as libvirt apis just tell me the max memory allocated.
2014-03-29 15:12 GMT+01:00 Eric Blake <eblake(a)redhat.com>:
On 03/29/2014 06:21 AM, Pasquale Dir wrote:
> I am looking at the shutdown method, but if the guest system is a desktop
> system, like for example ubuntu, it just has the effect to show a box
> prompting the user for a shutdown/reboot/ and such.
>
> I could enter the guest and change this default behaviour and it actually
> works..but I'd like for a way to send a shutdown command without doing
so.
>
> Is it possible?
Guest shutdown is ALWAYS a cooperative action. It sounds like your
guest defaults to an interactive shutdown when an ACPI shutdown request
is received. You can install qemu-guest-agent in your guest and send
shutdown via the agent instead of via ACPI - that may be a bit more
responsive at doing an immediate shutdown. But beyond that, no, there
is no way to guarantee a graceful guest shutdown without guest
cooperation. If you must stop a guest, and shutdown is taking too long
because the guest is not cooperating, then use the 'virsh destroy' command.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
11:58 a.m.
New subject: [libvirt-users] Programmatically force shutdown a guest: possible?
or you could do it through an acpi event. If you use kde, you can shut it down via dbus.
This is how I did it (as root):
su - username -c
"DBUS_SESSION_BUS_ADDRESS='unix:abstract=/tmp/dbus-vS7K32zzd7,guid=9eb3fedc45f523665b178a4d53373536'
qdbus-qt4 org.kde.ks
mserver /KSMServer logout 0 0 0"
In theory this should work too, if your dbus is compiled with support for X11 dbus-daemon
autolaunch:
su - username -c "DISPLAY=:0 qdbus-qt4 org.kde.ksmserver /KSMServer logout 0 0
0"
The trick is to know which user is currently logged in and to know/find out their
DBUS_SESSION_BUS_ADDRESS. The former is easy:
who | awk '!/pts/ {print $1}'
This will print the username of whoever is logged into X. If you get nothing, nobody is
logged on :0 and you could use wall to prompt all currently logged in users to log out,
give them a grace period of say one minute, then shutdown. If on the other hand you have
someone logged into X, you could use kdialog/zenity/xmessage to tell them they have say a
minute to quit whatever they are doing, then you can use the dbus to shutdown. It works
for KDE. I don't know if/how it works for GNOME/Unity/XFCE, etc.
As for the DBUS_SESSION_BUS_ADDRESS, if you use a standard/modern distribution this is
probably available in the user's shell environment variables already, so you need not
worry about it. Trouble is it may not be available outside the X session. You'll
need to change your KDE/GNOME/XFCE, etc start-up scripts to print this variable into a
file, which you can later source when you need it.
But you can control how your system will react on an acpi shutdown via the acpi hooks.
You don't have to get real fancy and worry about graceful shutdown, cause under
certain conditions it may not be possible to quit your graphical environment -- I've
had stubborn processes refuse to end and the shutdown is canceled. Read the dbus
documentation about the three numerical parameters (0 0 0 in this case) -- they deal with
session control, etc. Read up on acpi events as well and you should figure it out.
IvanK.
----- Original Message -----
From: "Pasquale Dir" <phate867(a)gmail.com>
To: "Eric Blake" <eblake(a)redhat.com>
Cc: libvirt-users(a)redhat.com
Sent: Sunday, March 30, 2014 11:47:23 AM
Subject: Re: [libvirt-users] Programmatically force shutdown a guest: possible?
Yes, you are right.
Listen, as the documentation is not very exaustive, can you explain briefly to me how a
guest agent works?
After installing it via the apt-get on the hypervisor (I am using ubuntu as host system)
how can I create a script which would do this?
That is waiting for an acpi signal and actually shut down the guest.
And what other operation can you actually do with a guest agent? I would be interested in
getting the current amount of memory the guest is using too...as libvirt apis just tell me
the max memory allocated.
2014-03-29 15:12 GMT+01:00 Eric Blake < eblake(a)redhat.com > :
On 03/29/2014 06:21 AM, Pasquale Dir wrote:
I am looking at the shutdown method, but if the guest system is a
desktop
system, like for example ubuntu, it just has the effect to show a box
prompting the user for a shutdown/reboot/ and such.
I could enter the guest and change this default behaviour and it actually
works..but I'd like for a way to send a shutdown command without doing so.
Is it possible?
Guest shutdown is ALWAYS a cooperative action. It sounds like your
guest defaults to an interactive shutdown when an ACPI shutdown request
is received. You can install qemu-guest-agent in your guest and send
shutdown via the agent instead of via ACPI - that may be a bit more
responsive at doing an immediate shutdown. But beyond that, no, there
is no way to guarantee a graceful guest shutdown without guest
cooperation. If you must stop a guest, and shutdown is taking too long
because the guest is not cooperating, then use the 'virsh destroy' command.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
_______________________________________________
libvirt-users mailing list
libvirt-users(a)redhat.com
https://www.redhat.com/mailman/listinfo/libvirt-users
4:24 p.m.
On 03/30/2014 02:47 AM, Pasquale Dir wrote:
Yes, you are right.
[please don't top-post on technical lists]
Listen, as the documentation is not very exaustive, can you explain
briefly
to me how a guest agent works?
There's two essential pieces - while you can add the pieces in either
order, both must be present before you have a guest agent channel.
1. You must expose the guest agent hardware to the guest. In libvirt,
this is done with the <channel> device:
http://libvirt.org/formatdomain.html#elementCharChannel
(look at the org.qemu.guest_agent.0 example)
Newer virt-manager has some gui elements for making this a bit easier to
set up.
2. You must install the guest agent in the guest, set to run as a
daemon. If the agent detects the hardware exposed by step 1, then you
have set up a communication channel between host and guest, where the
guest can react to host commands.
The idea is that the host issues one of the limited set of commands
understood by the agent protocol (the current list of commands
understood in qemu.git is here:
http://git.qemu.org/?p=qemu.git;a=blob;f=qga/qapi-schema.json;h=80edca14;...).
Libvirt has the 'virsh qemu-agent-command' for issuing any command not
already directly utilized by formal libvirt API. The agent then
receives that command over the virtual channel hardware, and does the
semantics of the command. The agent has been ported at least to Linux
and Windows guests. If there is an action you want the guest to do that
is not covered by those commands, then patches to the qemu list can be
proposed to expand the set.
After installing it via the apt-get on the hypervisor (I am using
ubuntu as
host system) how can I create a script which would do this?
For piece 2, you would use apt-get on your guest (not your host). The
only thing you do on the host is step 1 (xml modification to add the
device, if it isn't already present; newer virt-manager will add the xml
automatically).
That is waiting for an acpi signal and actually shut down the guest.
I'm not sure I followed this statement. The idea is that the 'virsh
shutdown' command knows two separate approaches to request guest
shutdown: one is by ACPI, the other by the agent. If the agent is wired
up, then that way is preferred; but if it is not wired up, or if it is
wired up but unresponsive (for example, if the agent is not actually
running because you forgot step 2 in the guest), then libvirt falls back
to ACPI (unless you told libvirt to specifically use only 1 of the two
possible shutdown methods).
And what other operation can you actually do with a guest agent? I would be
interested in getting the current amount of memory the guest is using
too...as libvirt apis just tell me the max memory allocated.
See the link I posted above for the current set of agent commands.
Unfortunately, I don't see an existing command that reports the guest's
view of memory usage.
On the other hand, I do know that newer qemu has the ability to get
information about guest memory usage when doing balloon commands (in
fact, older qemu also had that ability, except that the older way
REQUIRED the guest to cooperate, and that could lead to host deadlock
for non-cooperative guests, so it was withdrawn at the time; it was only
recently re-enabled when newer qemu made the interaction more of a
status poll instead of a lockstep query-response). If your qemu is new
enough, then libvirt's virDomainSetMemoryStatsPeriod() can control how
frequently you poll, and virDomainMemoryStats() can actually provide
details about the guest's view of memory usage according to what the
guest reported via the balloon driver.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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Pasquale Dir