Red Hat Bugzilla – Bug 241303
Unable to open the vms although the vms are running fine
Last modified: 2008-05-06 21:49:06 EDT
Description of problem: Unable to open the vms although the vms are running fine. Virtual Machine Manager stops reponding. Terminating is then the only option. Version-Release number of selected component (if applicable): 0.4.0 How reproducible: Always Steps to Reproduce: 1. Start Virtual Machine Manager (VMM) 2. Start a few vms - qemu with hvm enabled vms; observe that the console of individual vms are working fine 3. Exit VMM; start VMM; Now try opening one of the vm that was started in the above step; observe VMM doesn't respond anymore; terminating it is the only way. Actual results: VMM just hangs without responding. Expected results: VMM to open the console of individual vm successfully. Additional info: on AMD 5600, with hvm support.
When VMM is unable to open the console of the vm in question, then, only then, the vm's qemu process starts consuming more cpu than usual (say from 1% CPU utilisation it'd often jump to 10-20%, but not too much). After that happens, VMM will never recover, forcing me to the forceful termination of it. Weird. Whether VMM is working or not, the individual vms themselves are quite unaware of the VMM's problem & continue to function normally (tested over, say an SSH session to the Linuxy/Unixy vms). Of course, it'd be nice to have a reachable/working console to each vm, no matter how many times VMM is restarted.
Looking at the Xen codebase, it appears they are missing a data corruption bugfix in the VNC server which will (randomly) hit after a VNC client disconnects. I'm almost certain you're hitting this, since the behaviour you describe with high CPU load & hangs upon subsequent connects match the symptoms of the bug.
Created attachment 155448 [details] Fix handling of file descriptors on VNC client disconnect This is the patch applied to upstream QEMU. Hopefully it will work with QEMU 0.8.0 without too much further work.
Sounds good. If I may request you to provide me the rpm version of the packages involved, and if you do :-), I'm quite keen to have it tested. (Fedora 7 test 4 system with up to date updates has qemu-0.9.0-2.fc7. Would the above fix be applicable there also?) Thanks for a quick response & analysis of the problem. I really appreciate that.
The 'qemu' RPM is not actually used by Xen at all - Xen has forked the QEMU code and maintains its own private copy. I'll be pushing out this fix in an updated RPM asap.
Sorry I'm unable to understand whether the updates you are referring to are going to really address my problem due to my own ignorance. Sorry if this is an FAQ: I have only KVM based qemu vms (ie, only fully virtualised vms and no xen paravirtualised) in the system; in my case, do you think the updates (xen/qemu ??) you are talking about are going to help? $ rpm -qa|egrep -i 'xen|qemu|kvm|kernel|vnc|virt' kernel-2.6.21-1.3189.fc7 kernel-headers-2.6.21-1.3189.fc7 kvm-24-1 libvirt-0.2.2-4.fc7 libvirt-python-0.2.2-4.fc7 python-virtinst-0.103.0-3.fc7 qemu-0.9.0-2.fc7 virt-manager-0.4.0-2.fc7 vnc-libs-4.1.2-16.fc7 vnc-server-4.1.2-16.fc7 xen-libs-3.1.0-0.rc7.1.fc7 Thanks
In VMM, I'm able to reproduce the problem only against the guest with ID 1, I think. Or it's quite easy to reproduce against guest ID 1 & extremely hard against others.
change QA contact
Based on the date this bug was created, it appears to have been reported against rawhide during the development of a Fedora release that is no longer maintained. In order to refocus our efforts as a project we are flagging all of the open bugs for releases which are no longer maintained. If this bug remains in NEEDINFO thirty (30) days from now, we will automatically close it. If you can reproduce this bug in a maintained Fedora version (7, 8, or rawhide), please change this bug to the respective version and change the status to ASSIGNED. (If you're unable to change the bug's version or status, add a comment to the bug and someone will change it for you.) Thanks for your help, and we apologize again that we haven't handled these issues to this point. The process we're following is outlined here: http://fedoraproject.org/wiki/BugZappers/F9CleanUp We will be following the process here: http://fedoraproject.org/wiki/BugZappers/HouseKeeping to ensure this doesn't happen again.
This bug has been in NEEDINFO for more than 30 days since feedback was first requested. As a result we are closing it. If you can reproduce this bug in the future against a maintained Fedora version please feel free to reopen it against that version. The process we're following is outlined here: http://fedoraproject.org/wiki/BugZappers/F9CleanUp