Re: [CentOS-virt] Emergency help needed on host network randomly stop working.
On 10/12/11 12:43 AM, Magicloud Magiclouds wrote: Hi, This is a Centos 5.5 host with one xen guest. About 2 weeks ago, the host randomly lost network connection. By this I mean I could not connect to the services on it, or ping it. Also was the status of the guest. From serial console, I connected to the host, trying to see what happened. No clue (any error messages) in messages or dmesg. ifdown/ifup the interface did not help, either. Only rebooting was my only choice. Searching through Google, I got the information that some other guys met similar problem, and resolved by setting stp on with the bridge interface. I set it, too. And the problem still occurs. Any idea what I should check now? Thanks. When outage occurs, from the host these might be good things to look at and/or share with the list: ip link brctl show arp -n (arp -n from your next-hop router too) tcpdump -ln -i peth0 (try some activity; e.g. ping out to router, ping in from router) tcpdump -ln -i br0 (more activity) Depending on your xen bridge setup the bridge might be named eth0 or virbr0; peth0 might be different too. Eric ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Should I switch and if so what is the procedure
On 10/5/11 8:02 AM, Manuel Wolfshant wrote: I doubt that xen will be included as an option for RHEL 6 any time soon. So neither will it be for CentOS 6. not impossible that CentOS could have it as a value-add: http://lists.centos.org/pipermail/centos-virt/2011-July/002554.html I'm still running dom0 on CentOS 5 and am switching VMs and bare-metal non-Xen servers to 6. I figure I have enough time to wait to see what happens in 6.x (or 7?) before I will start worrying about 5 EOL. So long as I have hardware support I guess. Eric ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] CentOS 6 and KVM woes
When you showed the output of brctl show earlier only eth0 showed up. Does the VM NIC showed up attached to br0 when the VM is running? If so, then you can ping the VM from your host? That wouldn't involve the university switches so it would be a good first step before digging into packet dumping arp traffic... Sent from my mobile phone On Jul 16, 2011, at 4:58 PM, Trey Dockendorf treyd...@gmail.com wrote: On Fri, Jul 15, 2011 at 6:24 PM, Emmanuel Noobadmin centos.ad...@gmail.com wrote: On 7/16/11, Trey Dockendorf treyd...@gmail.com wrote: I have successfully bridged one of the server's NICs to br0, and I can ping the IP remotely that is assigned to br0, but none of the VMs that worked in 5.6's KVM are able to access the network. Please let me know what information would be useful to troubleshoot this. Could you try creating a new VM using the GUI tool, then check if the networking works from it? I was having problems with KVM and part of the troubleshooting process got me to try it on SL6, which finally led me to discover that the command line tool generated XML doesn't work as well as the GUI tool for some reason. So there's the possibility that it could be that the definitions created through virsh in 5.6 has the same issues in CentOS 6. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt I did try another VM (CentOS 6) via virt-manager with the same results. However I setup a test server at home, and am able to get both bridging and NAT to work so this may be an issue with the network on my server. It's a University network and their switches tend to play havoc with virtual servers even though I've been assured enough MAC addresses have been allowed on my port. How does one troubleshoot or provide debug information on a correctly or incorrectly functioning network bridge? As I contact my University's helpdesk I'd like to be able to point out the fault is not with my KVM server. Thanks - Trey ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] CentOS 6 and KVM woes
No experience with 6 here, but do your virsh-imported libvirt VM configs show devices...interface type=bridge...source bridge='br0'/ ? i.e. the bridge there matches the bridge name you're created with ifcfg scripts? Eric ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] [offtopic] RHEL guest inclusion (was: Reading the new 6.0 manual)
(off topic) On Jun 17, 2011, at 1:16 PM, Scott Dowdle wrote: Just to clarify... Red Hat's virtualization entitlement is for management/support from RHN. The way they sell RHEL... you can have 1 VM, 4 VMs or unlimited VMs. When I say VMs there I mean supported RHN subscribed RHEL installs where you register them with RHN and they get updates like any RHEL box would. So you are affectively getting 2, 5 or unlimited RHEL update entitlements. This is done by installing an additional package or two in the RHEL VM, and registering it with RHN so it knows it is a VM and RHN knows which physical host it is associated with. If you want to run any number of virtual non-RHEL OSes, go for it. They are not accounted for. The only thing accounted for are RHN subscriptions by physical or virtual machines. It isn't like virt-manager phones home... it does not. While I suspect that yes, the system won't stop you from doing this, I did hear from a Red Hat account manager when I was pricing out RHEL that you are supposed to purchase for the total number of guests of any operating system, not just RHEL. Or maybe I was misinformed. Anybody else familiar with this? Eric ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] KVM vs ESXi
On Wed, May 18, 2011 at 6:46 AM, Gilberto Nunes gilberto.nune...@gmail.com wrote: -Does KVM have a concept of virtual switches and and are they tied to physical NICs? ESXi allows me to create a vSwitch that isn't tied to a physical NIC so I can create a DMZ that exists solely within the host system. I'd like to replicate that if possible. Yes... You can use VirtManager to work with this feature... And in fact I'd say it's concept is *better*. KVM/libvirt just leverages the built-in virtual switching (bridging) support in Linux accessible through brctl. So you can create virtual bridges, tie ethernet devices to them, and have visibility into what's going on using standard tools like brctl and iproute2 tools if you'd like (instead of VirtManager). You can also use stuff like iptables to filter traffic going across bridges... Sad to admit it, but I have a Linux box functioning as a router which also runs KVM domains ... eth0 is a bridge port (so no IP address), the virtual switch br0 has both the router internal IP (.1) and the service-providing IP of the box (still the IP I used to manage the KVM host from before I was using it as the router), eth1 has multiple VLANs with IPs on our Fiber WAN and the local out-of-band network. The NICs of the guests are also attached to br0, naturally. And of course iptables is able to securely filter traffic across all that. It's a stopgap measure, but works flawlessly. If you want a NAT subnet, behind the scenes it's real Linux routing with iptables snat module (or masquerade). Your host-only network is a bridge without any hardware NICs attached as ports, only KVM NICs. And so on. Sublime! Eric PS, all the above is also true for running Xen on CentOS, though it comes with its own scripts for setting up the bridging instead of leveraging libvirt to do it ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
[CentOS-virt] KVM and Windows /use pmtimer
http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5/html/Virtualization/chap-Virtualization-KVM_guest_timing_management.html Want to get some more people's opinion on this: the above doc says to use the boot parameter /use pmtimer to use the RTC instead of the TSC for all time sources which resolves guest timing issues. One: does this have any bearing on whether the host has the constant_tsc flag (i.e. are all the sections that follow Configuring hosts without a constant Time Stamp Counter subordinate to it, or does that just have bearing on power management on that one CPU listed---AMD rev F)? Other question: http://support.microsoft.com/kb/938448 implies that for 2003 SP2 /use pmtimer shouldn't be needed as it will use the platform timer (RTC) if you have ACPI or APIC present. (By default, Windows Server 2003 Service Pack 2 (SP2) uses the PM timer for all multiprocessor Advanced Programmable Interrupt Controller (APIC) Hardware Abstraction Layers (HALs) or Advanced Configuration and Power Interface (ACPI) HALs.) Anybody have any experience as to whether this (using ACPI feature in KVM) resolves the timing issues without needing pmtimer explicitly set? Thanks, Eric PGP.sig Description: This is a digitally signed message part ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Xen on Centos 5.5 vs 5.3 and stability issues
Curious, RAID1 is soft/md, fakeraid or hardware? Also, are you using pygrub and then what is the kernel for the guests, or are you using a kernel from the host/which one? (I'm using almost-latest, ie last week, kernel on host and guest (pygrub) on hardware raid, haven't had any issues to date.) Eric Sent from my iPhone. Pardon the top-posting! On Oct 27, 2010, at 5:56 PM, Steven Ellis mail_li...@stevencherie.net wrote: I've recently upgraded a Centos 5.3 machine to Centos 5.5. The hardware isn't HVM capabile so I'm only running para-virt guests. Using a vanilla i386 kernel boots without, but the newer kernel-xen locks up the Dom0 after a couple of minute. I'm only booting into single user mode for these tests so no VMs are active. kernel-xen-2.6.18-128.1.10.el5 - no issues kernel-xen-2.6.18-194.17.4.el5 - lock up kernel-2.6.18-194.17.4.el5 - no issues For the moment I've switched back to the older Xen kernel, athough I'm still running the newer Xen Hypervisor. My current Xen packages are xen-3.0.3-105.el5_5.5 kernel-xen-2.6.18-194.17.4.el5 kernel-xen-2.6.18-128.1.10.el5 kmod-xfs-xen-0.4-2 xen-libs-3.0.3-105.el5_5.5 kernel-xen-devel-2.6.18-194.17.4.el5 kernel-xen-devel-2.6.18-128.1.10.el5 xen-devel-3.0.3-105.el5_5.5 Prior to the upgrade I had the following installed under Centos 5.3 kernel-xen-devel-2.6.18-128.1.6.el5 kernel-xen-2.6.18-128.1.10.el5 xen-libs-3.0.3-80.el5_3.2 xen-devel-3.0.3-80.el5_3.2 kmod-xfs-xen-0.4-2 kernel-xen-2.6.18-128.1.6.el5 kernel-xen-devel-2.6.18-128.1.10.el5 xen-3.0.3-80.el5_3.2 Booting Dom0 with kernel-xen-2.6.18-128.1.10.el5 everything appears to work normally and all of my Guests are up and running. If I boot with kernel-xen-2.6.18-194.17.4.el5 the boot normally gets to around udev and the system locks up. On a couple of occasions it did mange to boot but reported some files were corrupted. I'm worried that there is an issue running this kernel where the root file system is LVM on top of Raid 1. Anyone on this list have tips on diagnosing the issue, or come across a similar problem themselves. Steve ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] performance differences between kvm/xen
On Oct 25, 2010, at 8:14 AM, Todd Deshane wrote: I was also going to mention that we should look at scalability and performance isolation. Some references and previous studies here: http://todddeshane.net/research/Xen_versus_KVM_20080623.pdf http://clarkson.edu/~jnm/publications/isolation_ExpCS_FINALSUBMISSION.pdf http://clarkson.edu/~jnm/publications/freenix04-clark.pdf I only got as far as the top one. One concern: the nestled comment We believe that KVM may have performed better than Xen in terms of I/O due to disk caching makes me skeptical of the value of the results if this wasn't taken into consideration (in other words I think it is a much bigger problem than the aforementioned comment gives credit to, such that it ought to be at least addressed in the concluding remarks) ... for instance if my VM load-outs use all but ~384M of total memory (that being the amount I leave to the host, most of it used) then there's not going to be much extra RAM for memory cache/buffers with on the host side (depending greatly on what vm.swappiness camp you are in). Based on the author's result output [1] (since the VM parameters aren't given in the paper), as relates to a disk-intensive test they in effect gave 2G potential caching to Xen but ~4G to KVM. Based at least on the amount of free memory on my Xen/KVM hosts I don't think this host memor y cache bias can be assumed to be a bonus trait that would normally be present for KVM. (And of course a cache bias would be even more noticeable in the 256MB Phoronix test and in the 4x128M isolation tests [2] ...) [1] http://web2.clarkson.edu/projects/virtualization/benchvm/results/performance/ [2] http://web2.clarkson.edu/projects/virtualization/benchvm/results/isolation/xen/memory/specweb1/SPECweb_Support.20080614-100931.html BTW, I do realize you're pointing out that we should look at scalability and isolation, and here I am just giving critical feedback on a 3 year old paper ... yes you're right those are important! I just want to make sure the tests are fair ;-) Eric ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] KVM instance keep crashing
On Fri, Oct 15, 2010 at 2:57 AM, Poh Yong Hwang yong...@gmail.com wrote: Hi, The message log belongs to the guest which will become unresponsive from time to time. I have done the following and it report the same both on host as well as guest: [r...@localhost conf]# cat /proc/sys/kernel/tainted 65 65 = 1 + 64 1 - A module with a non-GPL license has been loaded, this includes modules with no license. 64 - The user has asked that the system be marked tainted. This could be because they are running software that directly modifies the hardware, or for other reasons. So, you won't be able to get any help from kernel people (probably) unless you can reproduce the problem without any binary kernel modules. http://www.linuxfoundation.org/collaborate/workgroups/technical-advisory-board-tab/kerneldriverstatement http://www.linuxfoundation.org/collaborate/workgroups/technical-advisory-board-tab/driverqa Look up some of GregKH's keynote addresses for more background. Eric ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] KVM instance keep crashing
On Oct 16, 2010, at 4:47 PM, Akemi Yagi wrote: [trim] However, what is strange is (now this is going to be off-topic here) that systems loaded with kmod-kvm show: $ cat /proc/sys/kernel/tainted 64 $ rpm -qi kmod-kvm | grep License Size: 4614945 License: GPLv2 Despite the fact the kvm module is GPL'd, the value of tainted is non-zero. This kernel is supposed to be NOT tainted. Could someone using kvm confirm this ? Following that thought, I hadn't thought to check that, but yes my KVM systems have that set to 64 as well. Probably not due to licensing, that would add a 1 bit which neither of us have (the OPer does). Note: one of my KVM systems that has '64' has HP Proliant Support Pack installed, which includes some kernel modules (GPLed though they be), the rest are Dell with OMSA packages installed, but I don't think OMSA loads any kernel modules (though 64 does appear to be related to userland, so PSP/OMSA could be related). Guess a third person with KVM and only distribution-based hardware support could chime in... Also, there wasn't a taint warning in the kernel traces on my machine (just had some kernel errors last week due to a perennial problem of mine: RHEL Cluster Suite) so 64 must be less significant (i.e. I still think the OP is going to need to get rid of the 1 flag before going to LKML). Maybe there wouldn't be a taint flag, but here it is. And remember this is from a machine has a tainted value of 64: Oct 15 07:57:44 ha7 kernel: INFO: task clvmd:6804 blocked for more than 120 seconds. Oct 15 07:57:44 ha7 kernel: echo 0 /proc/sys/kernel/hung_task_timeout_secs disables this message. Oct 15 07:57:44 ha7 kernel: clvmd D 810001003420 0 6804 1 6488 (NOTLB) Oct 15 07:57:44 ha7 kernel: 81033dfefdb8 0082 000a810a 0202 Oct 15 07:57:44 ha7 kernel: 011000f5 0009 81012d6fc040 81010b734080 Oct 15 07:57:44 ha7 kernel: 00089588d2b6e851 adc7 81012d6fc228 0001 Oct 15 07:57:44 ha7 kernel: Call Trace: Oct 15 07:57:44 ha7 kernel: [800646ac] __down_read+0x7a/0x92 Oct 15 07:57:44 ha7 kernel: [88505468] :dlm:dlm_user_request+0x2d/0x175 Oct 15 07:57:44 ha7 kernel: [8008c7d2] deactivate_task+0x28/0x5f Oct 15 07:57:44 ha7 kernel: [8012abc9] file_has_perm+0x94/0xa3 Oct 15 07:57:44 ha7 kernel: [8850c707] :dlm:device_write+0x2f5/0x5e5 Oct 15 07:57:44 ha7 kernel: [80016a17] vfs_write+0xce/0x174 Oct 15 07:57:44 ha7 kernel: [800988b7] recalc_sigpending+0xe/0x25 Oct 15 07:57:44 ha7 kernel: [800172e4] sys_write+0x45/0x6e Oct 15 07:57:44 ha7 kernel: [8005d116] system_call+0x7e/0x83 Further thought: I have other machines with HP PSP and Dell OMSA, why not check them? HP PSP, no virt: 0 Dell OMSA, no virt: 0 Dell OMSA, Xen Dom0: 0 HP PSP, VMware Server 2: 66 So I guess 64 is from kmod-kvm. (Hard to search online or the code for 64 taint flag when 64 bit is already so heavily all over the place bit...) Eric ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] KVM instance keep crashing
On Oct 14, 2010, at 1:38 AM, Poh Yong Hwang wrote: Hi, I have one KVM instance (centos 5) that keeps crashing and i see the message log with the following: Oct 14 16:24:48 localhost kernel: psmouse.c: Explorer Mouse at isa0060/serio1/input0 lost synchronization, throwing 1 bytes away. Oct 14 16:24:49 localhost kernel: BUG: soft lockup - CPU#0 stuck for 12s! [ntpd:2363] Oct 14 16:24:49 localhost kernel: CPU 0: Oct 14 16:24:49 localhost kernel: Modules linked in: backupdriver(PU) ipv6 xfrm_nalgo crypto_api autofs4 hidp rfcomm l2cap bluetooth lockd sunrpc talpa_pedevice(U) dm_mirror dm_multipath scsi_dh video backlight sbs power_meter hwmon i2c_ec dell_wmi wmi button battery asus_acpi acpi_memhotplug ac parport_pc lp parport floppy virtio_balloon virtio_pci ide_cd i2c_piix4 virtio_ring 8139too cdrom 8139cp pcspkr i2c_core virtio mii serio_raw dm_raid45 dm_message dm_region_hash dm_log dm_mod dm_mem_cache ata_piix libata sd_mod scsi_mod ext3 jbd uhci_hcd ohci_hcd ehci_hcd Oct 14 16:24:49 localhost kernel: Pid: 2363, comm: ntpd Tainted: P 2.6.18-194.3.1.el5 #1 [...] Afterwhich the instance become very sluggish and unresponsive. Please advise what could be the issue. I'm no expert on kernel stuff, but I thought I'd throw in a couple suggested points of clarification on your request since the above is not clear to me. Is the above in /var/log/message on the guest or host? Is it always an ntpd process on the CPU#0 stuck/soft lockup line? Does the soft lockup always occur after a psmouse.c warning? (Even so, the psmouse.c warning could maybe be a symptom of the CPU being stuck, not the cause...) What type of hardware is this? Noticing that is says tainted and I'm assuming this is the kernel (as I have no idea how a userland process, ntpd, could be tainted!), then you have a binary-distributed kernel module and you should probably try with that unloaded to see if the issue goes away. It could be a machine check error, but that's less likely I think. To double check, run the following in both the host and guest: cat /proc/sys/kernel/tainted This ORed value can be checked against the flags given in http://www.kernel.org/doc/Documentation/sysctl/kernel.txt Eric ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] which virtualization platform to choose
On Jul 26, 2010, at 12:03 PM, Gilberto Nunes wrote: [...] What you thing about??? As far as running 15 VMs, whether your hardware is suited to do that depends on how many spindles worth of SAS drives you have (improves concurrency), how busy your VMs are (IO and proc), how much the guests are swapping in case you're not giving them enough memory. And if you're not running virtio drivers, you should! I don't have the numbers, but several months ago I tested a few different Iometer meter workloads on Server 2003 R2 guests on PE1950 hardware against equivalently-matched VMs on the 1.x version of a popular proprietary product (dedicated memory instead of its default swap-mem-to-host-disk; also running the guest extensions), Xen on CentOS 5.4 with a then-recent build of GPLPV (meadowcourt.org/downloads) on the guests, and KVM (also CentOS 5.4) with somebody's build of unsigned virtio Windows drivers (was on a /~public_html from redhat.com I think). Results: Xen+GPLPV beat out KVM+virtio enough to be considered significant, but their difference seemed small compared to the margin they beat the other contender by. The proprietary one also had massive CPU load on the guest generated by running the test that the others didn't have. Obviously that's all very vague, but then again I'm sure somewhere I've accepted a EULA that says I'm not allowed to share benchmarking results for certain products :-). I'll be keeping Xen (and therefore CentOS 5.x) around to run Linux guests blazingly fast on still-usedful hardware. Everything else I'm (slowly) migrating to KVM in the interest of tracking with upstream. Xen's slight performance edge on Windows will be missed. YMMV. Eric ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Xen vs. KVM console
On Sun, Oct 25, 2009 at 7:29 PM, Dennis J. denni...@conversis.de wrote: Is there a way to configure the serial console in such a way that I don't lose a part of the functionality of the vnc console? You can specify multiple console= kernel cmdline params. On my machines with out-of-band serial, I have the console on both the first terminal and the serial port like this: kernel /vmlinuz-2.6.18-128.7.1.el5 ro root=/dev/lvm_main/dom0_root console=tty0 console=ttyS1,115200 You should be able to do something similar with console=tty0 console=ttyS0 Eric ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Slightly OT: GPLPV driver selection.
Centos wrote:
I'm in the middle of a (re-)install on a domU and looking for quick
replies as too which GPLPV to use on a Windows 2008 Server install.
Windows 32bit
Xen/Centos 64bit (x86_64)
[..]
Is the architecture ('arch') x86 (for the Windows domU 32bit
architecture) or x86_64 (for the arch version of Xen running)?
domU architecture, so in this case 32-bit. I'm using gplpv on quite a
few Server 2003 32-bit domUs running on 64-bit hardware 64-bit
Xen/CentOS-dom0.
Eric
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