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[libvirt] Re: kexec/kdump of a kvm guest?
by Mike Snitzer 27 Jul '08

27 Jul '08

On Thu, Jul 24, 2008 at 9:15 AM, Vivek Goyal <vgoyal(a)redhat.com> wrote: > On Thu, Jul 24, 2008 at 07:49:59AM -0400, Mike Snitzer wrote: >> On Thu, Jul 24, 2008 at 4:39 AM, Alexander Graf <agraf(a)suse.de> wrote: >> > As you're stating that the host kernel breaks with kvm modules loaded, maybe >> > someone there could give a hint. >> >> OK, I can try using a newer kernel on the host too (e.g. 2.6.25.x) to >> see how kexec/kdump of the host fairs when kvm modules are loaded. >> >> On the guest side of things, as I mentioned in my original post, >> kexec/kdump wouldn't work within a 2.6.22.19 guest with the host >> running 2.6.25.4 (with kvm-70). >> > > Hi Mike, > > I have never tried kexec/kdump inside a kvm guest. So I don't know if > historically they have been working or not. Avi indicated he seems to remember that at least kexec worked last he tried (didn't provide when/what he tried though). > Having said that, Why do we need kdump to work inside the guest? In this > case qemu should be knowing about the memory of guest kernel and should > be able to capture a kernel crash dump? I am not sure if qemu already does > that. If not, then probably we should think about it? > > To me, kdump is a good solution for baremetal but not for virtualized > environment where we already have another piece of software running which > can do the job for us. We will end up wasting memory in every instance > of guest (memory reserved for kdump kernel in every guest). I haven't looked into what mechanics qemu provides for collecting the entire guest memory image; I'll dig deeper at some point. It seems the libvirt mid-layer ("virsh dump" - dump the core of a domain to a file for analysis) doesn't support saving a kvm guest core: # virsh dump guest10 guest10.dump libvir: error : this function is not supported by the hypervisor: virDomainCoreDump error: Failed to core dump domain guest10 to guest10.dump Seems that libvirt functionality isn't available yet with kvm (I'm using libvirt 0.4.2, I'll give libvirt 0.4.4 a try). cc'ing the libvirt-list to get their insight. That aside, having the crash dump collection be multi-phased really isn't workable (that is if it requires a crashed guest to be manually saved after the fact). The host system _could_ be rebooted; whereby losing the guest's core image. So automating qemu and/or libvirtd to trigger a dump would seem worthwhile (maybe its already done?). So while I agree with you its ideal to not have to waste memory in each guest for the purposes of kdump; if users want to model a guest image as closely as possible to what will be deployed on bare metal it really would be ideal to support a 1:1 functional equivalent with kvm. I work with people who refuse to use kvm because of the lack of kexec/kdump support. I can do further research but welcome others' insight: do others have advice on how best to collect a crashed kvm guest's core? > It will be interesting to look at your results with 2.6.25.x kernels with > kvm module inserted. Currently I can't think what can possibly be wrong. If the host's 2.6.25.4 kernel has both the kvm and kvm-intel modules loaded kexec/kdump does _not_ work (simply hangs the system). If I only have the kvm module loaded kexec/kdump works as expected (likewise if no kvm modules are loaded at all). So it would appear that kvm-intel and kexec are definitely mutually exclusive at the moment (at least on both 2.6.22.x and 2.6.25.x). Mike

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[libvirt] virsh
by drew einhorn 25 Jul '08

25 Jul '08

Hi, I have virsh running in a remote ssh session in a dom0 xen VM, it is presenting a virtual console for a domU vm running a RHEL5 installer The RHEL5 is going astray setting up the network using DHCP, I want to do Ctrl-Alt-Fn to view the installer log files, and access a shell prompt. But the Ctrl-Alt-Fn is being consumed by the laptop running the remote ssh ssh session. How do I get the virsh to send Ctrl-Alt-Fn to the domU console? -- Drew Einhorn

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[libvirt] [PATCH]: Utterly trivial comment cleanups in src/domain_conf.c
by Chris Lalancette 25 Jul '08

25 Jul '08

The subject pretty much says it all, except for the minor fact of using "domain.xml" in the xmlReadDoc(). This cleanup really just makes the code easier to read. Signed-off-by: Chris Lalancette <clalance(a)redhat.com>

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[libvirt] Problems when using libvirt-cim provider
by SHAN, CHUN -HCHBJ 25 Jul '08

25 Jul '08

Hi,all: I am trying to use libvirt API and libvirt-cim now. After installed them successfully, I can see the "Virt_*****" providers using "cimprovider -l -s"commond. My cimom is pegasus. Then I used wbemcli as cim client. But when I used "wbemcli ei" to enumerate instances of a specified class,for example,Xen_DiskPool, error code was: wbemcli:Cim(1) CIM_ERR_FAILED: A general error occurred that is not covered by a more specific error code:"For provider Virt_DevicePool the library name was empty. Check provider registered location". Could you please help me to solve this problem? Did it mean that the providers were not registered correctly? But I "make postinstall" the provider and no errors occourred. Thank you! Regards, Chun Shan Disclaimer: The contents of this e-mail, and its attachments, if any, are confidential and may be protected by law against any unauthorized use. If you have received this e-mail by mistake or have reason to believe that you are not the intended recipient, please notify the sender by reply e-mail as soon as possible and delete it from your computer system immediately thereafter. If you are not the intended recipient, you must not copy this e-mail or attachment or disclose the contents to any other person. While we have made every effort to keep our network virus free, we take no responsibility for any computer virus which might be transferred by way of this e-mail.

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[libvirt] PATCH Remove unused openvz code
by Daniel P. Berrange 25 Jul '08

25 Jul '08

The openvz driver currrently generates a compile warning due to this unused function. If no one objects I'll shortly remove it. I intend to turn on openvz and LXC driver compilation for the nightly builds to get more testing coverage Daniel diff -r 59140de4e7a9 src/openvz_driver.c --- a/src/openvz_driver.c Mon Jul 21 18:27:29 2008 +0100 +++ b/src/openvz_driver.c Tue Jul 22 22:12:22 2008 +0100 @@ -91,32 +91,11 @@ unsigned int flags ATTRIBUTE_UNUSED); static int openvzDomainUndefine(virDomainPtr dom); -static int convCmdbufExec(char cmdbuf[], char *cmdExec[]); static void cmdExecFree(char *cmdExec[]); static int openvzGetProcessInfo(unsigned long long *cpuTime, int vpsid); struct openvz_driver ovz_driver; - -static int convCmdbufExec(char cmdbuf[], char *cmdExec[]) -{ - int i=0, limit = OPENVZ_MAX_ARG - 1; - char cmdWord[CMDOP_LEN]; - while(*cmdbuf) - { - if(i >= limit) - { - cmdExec[i] = NULL; - return -1; - } - sscanf(cmdbuf, "%s", cmdWord); - cmdbuf += strlen(cmdWord); - while(*cmdbuf == ' ') cmdbuf++; - cmdExec[i++] = strdup(cmdWord); - } - cmdExec[i] = NULL; - return i; -} static void cmdExecFree(char *cmdExec[]) { -- |: Red Hat, Engineering, London -o- http://people.redhat.com/berrange/ :| |: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|

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[libvirt] Couple qemu driver bugs after xml refactoring
by Cole Robinson 25 Jul '08

25 Jul '08

Hi all, I've hit a couple bugs in the qemu driver with the recent domain xml refactoring. I've debugged them but in both cases I'm not sure what the optimal solutions are, so I'm just laying them out here: 1) Previously defining a qemu guest without a 'listen' address specified in the graphics tag would default to 127.0.0.1 (hardcoded in qemu_driver->vncListen). Current xml doesn't set this default, and will build a qemu command line with an entry like '-vnc (null):1'. Not sure if the default should be set at the parsing level or the driver level. 2) If a cpuset isn't specified, def->cpumask is null. However qemudInitCpus from qemu_driver.c doesn't know how to handle this, causing libvirtd to crash. This function is also using QEMUD_CPUMASK_LEN which I think should be replaced with VIR_DOMAIN_CPUMASK_LEN. I tried the obvious fix of just skipping the dependent code if cpumask is null, but there still seemed to be problems and I didn't dig much deeper. Thanks, Cole

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[libvirt] Double free in test driver error handling (0.4.4)
by Tóth István 25 Jul '08

25 Jul '08

While debugging the libvirt-java error handling problem, Ive found that if I call the test driver with a bad uri, the application instantly bombs with a double free error. Try to run the attached test program to trigger the bug. regards István #include <libvirt/libvirt.h> #include <stdio.h> int main(){ int ret=virInitialize(); virConnectOpen("test:///defaultt"); }

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[libvirt] [PATCH]: libvirt.h: very xen centric
by Guido Günther 25 Jul '08

25 Jul '08

Hi, while reading through that I noticed libvirt.h is quiet xen centric. Purely cosmetic patch attached, -- Guido

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[libvirt] [PATCH] qemudOpenMonitor: fix open(2) error check
by Guido Günther 25 Jul '08

25 Jul '08

Hi, open returns -1 on failure. Pointed out by Guido Trotter on: http://bugs.debian.org/492250 Patch against current CVS attached. -- Guido

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[libvirt] [PATCH] fix Relax-NG pattern matching
by John Levon 25 Jul '08

25 Jul '08

Don't use unescaped meta-characters. Signed-off-by: John Levon <john.levon(a)sun.com> Index: docs/libvirt.rng =================================================================== RCS file: /data/cvs/libvirt/docs/libvirt.rng,v retrieving revision 1.9 diff -u -r1.9 libvirt.rng --- docs/libvirt.rng 10 Jul 2008 08:05:39 -0000 1.9 +++ docs/libvirt.rng 24 Jul 2008 16:40:16 -0000 @@ -840,7 +840,7 @@ </define> <define name='domainName'> <data type='string'> - <param name="pattern">[A-Za-z0-9_.:/\+\-&-]+</param> + <param name="pattern">[A-Za-z0-9_\.\+\-&:/]+</param> </data> </define> <define name='genericName'> @@ -860,22 +860,22 @@ </define> <define name='filePath'> <data type='string'> - <param name="pattern">[a-zA-Z0-9_\+\-%./&]+</param> + <param name="pattern">[a-zA-Z0-9_\.\+\-&/%]+</param> </data> </define> <define name='absFilePath'> <data type='string'> - <param name="pattern">/[a-zA-Z0-9_\+\-%./&]+</param> + <param name="pattern">/[a-zA-Z0-9_\.\+\-&/%]+</param> </data> </define> <define name='devicePath'> <data type='string'> - <param name="pattern">/[a-zA-Z0-9_\+\-%/]+</param> + <param name="pattern">/[a-zA-Z0-9_\+\-/%]+</param> </data> </define> <define name='deviceName'> <data type='string'> - <param name="pattern">[a-zA-Z0-9_\-:./]+</param> + <param name="pattern">[a-zA-Z0-9_\.\-:/]+</param> </data> </define> <define name='addrMAC'>

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