Hi All, Debian Lenny amd64, xen 3.2.1 For the first time in a couple of years, I had a paravirt VM freeze on me the other day, running at 400% CPU in xm list (4 vcpu). The dom0 machine was still operating correctly, but the domU was not accessible (either via ssh or xm console). Other paravirt instances on the same dom0 were also still running correctly. After running xm destroy and recreating the vm, it was accessible again. Nothing in the dom0 or domU logs indicate any errors, just that everything in the domU froze about the same time. Has anyone seen this and could offer a reason why or advise how best I might be able to troubleshoot this? This sounds like it''s a problem with something inside the VM rather than Xen, however why couldn''t I connect with xm console? Best Regards, Mark _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Mark Adams wrote:>Debian Lenny amd64, xen 3.2.1 > >For the first time in a couple of years, I had a paravirt VM freeze on >me the other day, running at 400% CPU in xm list (4 vcpu). The dom0 >machine was still operating correctly, but the domU was not accessible >(either via ssh or xm console). Other paravirt instances on the same >dom0 were also still running correctly. After running xm destroy and >recreating the vm, it was accessible again. > >Nothing in the dom0 or domU logs indicate any errors, just that >everything in the domU froze about the same time. > >Has anyone seen this and could offer a reason why or advise how best I >might be able to troubleshoot this? This sounds like it''s a problem with >something inside the VM rather than Xen, however why couldn''t I connect >with xm console?Yes, I get this as well. stop xend - /etc/init.d/xend stop find the process id for xenconsoled - ps axl | grep xenconsoled kill it start xend - /etc/init.d/xend start The DomU will resume where it was. It''s sort of second nature - Nagios reports a virtual server as down, first thing I do is log into Dom0 to check. See this thread : http://lists.xensource.com/archives/html/xen-users/2009-07/msg00326.html -- Simon Hobson Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed author Gladys Hobson. Novels - poetry - short stories - ideal as Christmas stocking fillers. Some available as e-books. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Hi There, Thanks for your response - please see inline. On Mon, Jul 12, 2010 at 10:42:24AM +0100, Simon Hobson wrote:> Mark Adams wrote: > >> Debian Lenny amd64, xen 3.2.1 >> >> For the first time in a couple of years, I had a paravirt VM freeze on >> me the other day, running at 400% CPU in xm list (4 vcpu). The dom0 >> machine was still operating correctly, but the domU was not accessible >> (either via ssh or xm console). Other paravirt instances on the same >> dom0 were also still running correctly. After running xm destroy and >> recreating the vm, it was accessible again. >> >> Nothing in the dom0 or domU logs indicate any errors, just that >> everything in the domU froze about the same time. >> >> Has anyone seen this and could offer a reason why or advise how best I >> might be able to troubleshoot this? This sounds like it''s a problem with >> something inside the VM rather than Xen, however why couldn''t I connect >> with xm console? > > Yes, I get this as well. > > stop xend - /etc/init.d/xend stop > find the process id for xenconsoled - ps axl | grep xenconsoled > kill it > start xend - /etc/init.d/xend startI don''t think this is the same issue. I successfully stopped the vm with xm destroy ID and then started it again with xm create vm.cfg.> > The DomU will resume where it was. It''s sort of second nature - Nagios > reports a virtual server as down, first thing I do is log into Dom0 to > check. > > See this thread : > http://lists.xensource.com/archives/html/xen-users/2009-07/msg00326.htmlThanks, In your link it says people can connect to the instances but that they are using all resources. I couldn''t connect with console or ssh at all until I destroyed and created the machine. I''ve got a number of Lenny Xen servers running in this way and haven''t had this issue before. As I understand it 32bit dom0 in lenny is a bit flakey, but amd64 is ok. This is certainly true from my experience (until this glitch!) Cheers, Mark _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Mark Adams wrote:>I don''t think this is the same issue. I successfully stopped the vm with >xm destroy ID and then started it again with xm create vm.cfg.Yup, that''s what I did the first time or two. Worth trying next time. The description is slightly different to what I have as well - can''t connect to console (or rather, can connect but nothing happens), and the machine is not visible on the network. -- Simon Hobson Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed author Gladys Hobson. Novels - poetry - short stories - ideal as Christmas stocking fillers. Some available as e-books. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Mark Adams wrote:>Sorry to drag up this thread... but can you confirm that your actions to >correct this do not effect any other VM''s running on the box?Yes, stopping xenconsoled is safe, it doesn''t affect any running guests. I assume if you leave it stopped then eventually the others will hang on output to the console, but I''ve never tried it. If you accidentally kill xenstored by mistake then that''s a different matter, I believe that would kill your guests ! -- Simon Hobson Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed author Gladys Hobson. Novels - poetry - short stories - ideal as Christmas stocking fillers. Some available as e-books. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users