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1613 discussions

Re: [CentOS-virt] moving from Xen to KVM
by Christopher G. Stach II 18 Mar '10

18 Mar '10

----- "Dave Augustus" <davea(a)ingraftedsoftware.com> wrote: > I finally realized that when running Xen and in Dom0, Xen hides the > AMD-V in /proc/cpuinfo Really? dom0: flags : fpu tsc msr pae mce cx8 apic mtrr mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt lm 3dnowext 3dnow constant_tsc pni monitor cx16 lahf_lm cmp_legacy svm cr8_legacy guest: flags : fpu tsc msr pae mce cx8 apic mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt lm 3dnowext 3dnow constant_tsc pni monitor cx16 lahf_lm cmp_legacy svm cr8_legacy > (...more reasons to move to KVM) I have a hunch that you are going to do whatever you are told to do and that you really have no idea what is going on. Can we get more "Hey, I'm told KVM is cool so I'm migrating all of my production servers to it because the free OS of my choice may not support it in a year or two after I leave my current suckjob position and I hear, since I don't read mainline kernel mailing lists religiously and keep only a superficial idea in my head about kernel development, since I really have no idea what 'kernel development' means, that KVM is the only Jesus-approved way of doing things" threads? None of you seem to have have a head for any of this, it seems. Maybe you're just working for Billy's Interwebs-r-Us and keeping Sally's Nail Shop going strong, but the last time I checked, the "ent" in CentOS stood for "enterprise". Here are a few tips: 1. Fuck KVM. 2. Stick with Xen because there is quite a lot of time until 5 is EOL'd and if you haven't noticed, it's actually a mature technology. 3. Figure out what you are going to do with Sally's Nail Shop in the meantime. If you have time to fuck everything up in your environment with KVM, you can probably save 20% or more optimizing your environment and even more with proper capital investments and training. 4. Figure out how either a) non-critical/enterprise services would ever be served by KVM's features or lack thereof, or b) you are going to CYA when you can't guarantee an SLA. 5. Spend more time on KVM dev lists instead of posting here and annoying others with your butthurt KVM-won't-work posts, as it's not even supported upstream. -- Christopher G. Stach II http://ldsys.net/~cgs/

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What kernel params to use with KVM hosts??
by carlopmart 17 Mar '10

17 Mar '10

Hi all, I order to reach maximum performance on my centos kvm hosts I have use these params: - On /etc/grub.conf: kernel /vmlinuz-2.6.18-164.11.1.el5 ro root=LABEL=/ elevator=deadline quiet - On sysctl.conf # Special network params net.core.rmem_default = 8388608 net.core.wmem_default = 8388608 net.core.rmem_max = 16777216 net.core.wmem_max = 16777216 net.ipv4.tcp_rmem = 1048576 4194304 16777216 net.ipv4.tcp_wmem = 1048576 4194304 16777216 # Disable netfilter on bridges. net.bridge.bridge-nf-call-ip6tables = 0 net.bridge.bridge-nf-call-iptables = 0 net.bridge.bridge-nf-call-arptables = 0 # Virtual machines special kernel params vm.swappiness = 0 Do I need to configure something more?? Any tips?? Thanks. -- CL Martinez carlopmart {at} gmail {d0t} com

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get xen name from guest
by Ryan Pugatch 17 Mar '10

17 Mar '10

Hello, Is it possible to get the name that was set in a VM's xen config file from the guest machine? I'm interested in having my kickstart launch a script that can configure hostname, but to do that it would need to get the name set in the config. Thanks, Ryan

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reboot guest on panic
by Norman Gaywood 16 Mar '10

16 Mar '10

I have a guest that keeps crashing and want to automatically reboot it when it crashes. See: xen PV guest kernel 2.6.32 processes lock up in D state https://bugzilla.redhat.com/show_bug.cgi?id=550724 if you want to look at the details on the crashing. Anyway, I boot the guest with the kernel command line parameter: hung_task_panic=1 I have kernel.panic = 15 in the guest /etc/sysctl.conf In the guest config file in dom0 I have: on_poweroff = "destroy" on_reboot = "restart" on_crash = "restart" The guest manages to panic when it detects the hung tasks and I get this on the guest console: Kernel panic - not syncing: hung_task: blocked tasks Rebooting in 15 seconds.. However, it never restarts. It just hangs around until I do a xm destroy <guest> xm create <guest> Have I missed something? -- Norman Gaywood, Computer Systems Officer University of New England, Armidale, NSW 2351, Australia ngaywood(a)une.edu.au Phone: +61 (0)2 6773 3337 http://mcs.une.edu.au/~norm Fax: +61 (0)2 6773 3312 Please avoid sending me Word or PowerPoint attachments. See http://www.gnu.org/philosophy/no-word-attachments.html

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Re: [CentOS-virt] reboot guest on panic
by Christopher G. Stach II 14 Mar '10

14 Mar '10

----- "Norman Gaywood" <ngaywood(a)une.edu.au> wrote: > Well yes, seems I've hit trouble this time. Was expecting some trouble > with the desktop apps and was happy to deal with that. I was not > expecting significant kernel trouble however. It's Fedora. It's *always* broken. > Rebuilding a modern desktop distro with an older kernel is a lot of > work. It's not that bad. The only things you really need to match up are glibc and the kernel. Beyond that, most things are reasonably source compatible with a slightly older glibc. I don't think you would need to go that far, though. What do you need in Fedora that you can't get in the almost equally substandard desktop experience from CentOS or any other enterprise distribution? (I use CentOS as my primary desktop.) > That's what distributions are for right? Gentoo? :) -- Christopher G. Stach II http://ldsys.net/~cgs/

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Re: [CentOS-virt] gpl pv drivers and Centos 5.4
by F M 14 Mar '10

14 Mar '10

TX to you both of you for the info. I will test these drivers tomorrow. Regards, F Regards,----- Original Message ----- From: "Pasi Kärkkäinen" <pasik(a)iki.fi> To: "Discussion about the virtualization on CentOS" <centos-virt(a)centos.org> Sent: Sunday, March 14, 2010 9:12:42 AM Subject: Re: [CentOS-virt] gpl pv drivers and Centos 5.4 On Sat, Mar 13, 2010 at 07:17:58AM -0500, F M wrote: > Hello, > I am using Windows XP/2003 and 2008 under Xen. What is the correct version of gpl pv drivers for Windows under Centos 5.4 Dom0 ? rpm -q xen said 3.0.3.x but xen info said 3.1.x > Xen hypervisor in EL5 is version 3.1.2 + a lot of patches from Redhat and from newer Xen versions. Xen tools in EL5 (xm/xend etc) are based on version 3.0.3 + patches. -- Pasi _______________________________________________ CentOS-virt mailing list CentOS-virt(a)centos.org http://lists.centos.org/mailman/listinfo/centos-virt

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gpl pv drivers and Centos 5.4
by F M 14 Mar '10

14 Mar '10

Hello, I am using Windows XP/2003 and 2008 under Xen. What is the correct version of gpl pv drivers for Windows under Centos 5.4 Dom0 ? rpm -q xen said 3.0.3.x but xen info said 3.1.x Regards,

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Re: [CentOS-virt] reboot guest on panic
by Christopher G. Stach II 14 Mar '10

14 Mar '10

----- "Norman Gaywood" <ngaywood(a)une.edu.au> wrote: > > If your guest's state is corrupted, you can't rely on its behavior. > For that reason, you should set up a watchdog and only rely on the > panic behavior as a preliminary measure. > > I figured that I had setup a watchdog with the hung_task_panic=1 guest > parameter. Is there another way of setting up a watchdog in this case? Internal watchdogs are seldom as effective as you need them to be. I meant an external one. There was talk in the past about a Xen watchdog driver, but I don't know where that ended up. (I use existing code that works for me, so I haven't kept up.) There are various ways to set one up. You can do it on your own with a couple of scripts and xenstore, if you're so inclined. If not, there are a lot of existing examples and projects that will handle it for you. This one that uses QEMU and unfortunately only KVM is decent and should give you enough ideas on how to implement one: http://rwmj.wordpress.com/2010/03/03/what-is-a-watchdog/ -- Christopher G. Stach II http://ldsys.net/~cgs/

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unable to get domain status from libvirt & KVM
by Tom Georgoulias 12 Mar '10

12 Mar '10

I have a python script that monitors the VMs on physical host servers running Xen, but the script doesn't work properly on a server I just built with KVM. The script runs as a non-root user (same on all servers) and simply gathers some details on the status and names of the domains running on the host. Both Xen and KVM servers are running the same version of libvirt (libvirt-0.6.3-20.1.el5_4) and have the same, default /etc/libvirt/libvirtd.conf config file. To troubleshoot, I've been running python interactively. Here's how my Xen servers behave: $ python Python 2.4.3 (#1, Sep 3 2009, 15:37:37) [GCC 4.1.2 20080704 (Red Hat 4.1.2-46)] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> import libvirt >>> conn = libvirt.openReadOnly(None) >>> domains = conn.listDomainsID() >>> print domains [0, 3, 15, 16, 21, 24, 26, 30, 32, 36, 38, 41, 43, 45, 47, 49, 51, 55, 63, 67] >>> When I try the same thing on the KVM server: $ python Python 2.4.3 (#1, Sep 3 2009, 15:37:37) [GCC 4.1.2 20080704 (Red Hat 4.1.2-46)] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> import libvirt >>> conn = libvirt.openReadOnly(None) 14:33:07.303: error : No vport operation path found for host0 14:33:07.320: error : No vport operation path found for host4 14:33:07.325: error : No vport operation path found for host3 14:33:07.367: error : No vport operation path found for host1 14:33:07.368: error : No vport operation path found for host2 >>> domains = conn.listDomainsID() >>> print domains [] >>> (The vport stuff is weird, but I found this posting that suggests its harmless (http://www.mail-archive.com/libvir-list@redhat.com/msg17477.html) so I'm ignoring it.) However, when logged in as root on the KVM server, it works just like my Xen servers: # python Python 2.4.3 (#1, Sep 3 2009, 15:37:37) [GCC 4.1.2 20080704 (Red Hat 4.1.2-46)] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> import libvirt >>> conn = libvirt.openReadOnly(None) >>> domains = conn.listDomainsID() >>> print domains [1] Again, on the KVM server, plain old "virsh list" with the debug level set to "2" $ export LIBVIRT_DEBUG=2 $ virsh list 14:21:06.532: error : No vport operation path found for host0 14:21:06.550: error : No vport operation path found for host4 14:21:06.555: error : No vport operation path found for host3 14:21:06.598: error : No vport operation path found for host1 14:21:06.599: error : No vport operation path found for host2 14:21:06.615: info : No security driver available Id Name State ---------------------------------- Permissions in /var/run/libvirt: # ls -ld /var/run/libvirt/* srwx------ 1 root root 0 Feb 5 08:53 /var/run/libvirt/libvirt-sock srwxrwxrwx 1 root root 0 Feb 5 08:53 /var/run/libvirt/libvirt-sock-ro drwxr-xr-x 2 root root 4096 Jan 21 14:38 /var/run/libvirt/network drwxr-xr-x 2 root root 4096 Oct 20 18:50 /var/run/libvirt/qemu Can someone provide some tips on what else I can check, if this might be a bug, or point out any mistakes that I might've made? Any help is appreciated. Thanks, Tom

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Logrotate/cron and major I/O contention with KVM.
by Steven Ellis 11 Mar '10

11 Mar '10

Is anyone else having major I/O peaks due to logrotate or other jobs running simultaneously across multiple guests. I have one KVM server running Centos 5.4 with local disk that is seriously suffering as most of the guests rotate their syslog at the same time. Looking at the KVM server I'm seeing 11:00:01 PM CPU %user %nice %system %iowait %steal %idle 03:40:01 AM all 0.07 0.00 2.74 0.93 0.00 96.26 03:50:01 AM all 0.07 0.00 1.17 1.18 0.00 97.58 04:00:01 AM all 0.08 0.00 1.51 0.82 0.00 97.59 04:10:02 AM all 0.53 0.03 15.31 51.61 0.00 32.53 04:20:01 AM all 0.28 0.12 4.12 22.21 0.00 73.27 04:30:01 AM all 0.07 0.00 0.80 1.21 0.00 97.92 04:40:01 AM all 0.07 0.00 2.60 1.81 0.00 95.52 04:50:01 AM all 0.08 0.00 0.79 1.44 0.00 97.69 On one of the guests running Centos 4.6 the impact is so bad I get DMA timeout errors in the syslog, and occasional kernel panics. Mar 11 04:05:04 localhost kernel: hda: dma_timer_expiry: dma status == 0x21 Mar 11 04:05:14 localhost kernel: hda: DMA timeout error Mar 11 04:05:14 localhost kernel: hda: dma timeout error: status=0x50 { DriveReady SeekComplete } Mar 11 04:05:14 localhost kernel: Mar 11 04:05:14 localhost kernel: ide: failed opcode was: unknown Mar 11 04:05:59 localhost kernel: hda: dma_timer_expiry: dma status == 0x21 Mar 11 04:06:14 localhost kernel: hda: DMA timeout error Mar 11 04:06:14 localhost kernel: hda: dma timeout error: status=0x50 { DriveReady SeekComplete } One reference I've found is at * http://lonesysadmin.net/linux-virtual-machine-tuning-guide/ This suggests avoiding running scheduled jobs simultaneously across guests, and suggests using a random sleep. Does anyone else have suggestions on reducing the impact of cron/logrotate. -- *Steven Ellis - Director of Worldwide Engineering,* *Bulletin.Net Inc* - http://www.bulletin.net/

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