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] Slightly OT: Centos KVM Host/Guest functions and LVM considerations
On 9/14/11 1:41 PM, Chris Wik wrote: > On 14.09.2011, at 18:51, Jeff Boyce wrote: > [...] >> The more I >> read the more confused I get about understanding the hierarchy of the >> storage (disks.RAID.[PV,VG,LV].Partition.Image File) and how I should be >> looking at organizing and managing the file system for my functions. With >> this I don't even understand it enough to ask a more specific question. > > Some examples might help. This is what I do: > > Disks -> RAID -> PV -> VG -> LV -> VM filesystem / > Disks -> RAID -> PV -> VG -> LV -> VM filesystem /boot > Disks -> RAID -> PV -> VG -> LV -> VM filesystem swap > > I like this method because it makes it easy to take a snapshot of the VM > filesystem and run a backup from dom0 (yields a consistent backup with no > interruption to the running VM) > > or > > Disks -> RAID -> PV -> VG -> LV -> VM's partition map -> VM filesystems (/, > /boot, swap, etc) > > or > > Disks -> RAID -> PV -> VG -> LV -> VM's partition map -> PV -> VG -> LV -> VM > filesystems > > Which setup you choose depends on how much flexibility you want, and whether > you want to manage LVM inside the VM or not. LVM inside the guest allows more > flexibility inside the VM... I do host LVs as guest whole disk block devices (second alternative); in my experience guest installs in anaconda+kickstart are easier on single drive vs. multiple LVs passed (first alternative). I don't think KVM can direct LVs to partitions like Xen can, aka lv_root->xvda1, lv_var->xvda2, so I think your filesystems would have their own vda, vdb, vdc etc ... just a hunch though). Also it's a lot of LVs to manage in the host depending on how many partitions you do for systems (4 or 5 VMs with half dozen partitions each...) Chris, do you fsync your guest before you snapshot the LV guest partition to make sure your filesystem is clean? First alternative provides *very* easy access to filesystems from the host. For second alternative, "kpartx" from the host lets you access the partitions from the host if you need to. Third alternative is very confusing if you want to mount guest volumes from host for any sort of emergency data needs, because the LVM vg names can conflict (vg_main in guest can't coexist with vg_main in host). 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 wrote: > > > On Fri, Jul 15, 2011 at 6:24 PM, Emmanuel Noobadmin > wrote: > On 7/16/11, Trey Dockendorf 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 .. ? 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 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
Re: [CentOS-virt] Where is my qemu command?
On Wed, Apr 27, 2011 at 2:29 AM, Jussi Hirvi wrote: [...] > There may be a reason > to why it is hidden... But I may have to give it a try soon. I suspect the reason it is hidden is that KVM is "best" used with a front-end like libvirt, which would provide the interface to add a disk (e.g. virsh attach-disk). (Unfortunately libvirt frustrates me with the way it's difficult to manage config files for your guests (like I could with /etc/xen/* ...) with cfengine/puppet. Files in /etc/libvirt/qemu are not friendly to direct edits.) Eric ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Xen version
On Dec 16, 2010, at 1:01 AM, Paul Piscuc wrote: > Hi, > > We are thinking of using CentOS with XEN in production, but we are facing > some issues regarding the 3.0.3 version of the xen hypervisor and windows > paravirtualization. The drivers we are using are from here > (http://wiki.xensource.com/xenwiki/XenWindowsGplPv). The solution we found is > upgrading to xen 3.4.2, using a strange repository (gitco.de), and everything > seems to work. Now the question is: would you recomand using the 3.0.3 kernel > provided by CentOS in production and searching for other paravirtualization > drivers, or go with 3.4.2? Is this version of the hypervisor stable? While gitco isn't really that "strange" (as I'm pretty sure its widely deployed judging from comments on this list) I've never got around to upgrading to it. I've got more than a dozen Windows VMs: XP, 2003 32 and 64 bit, all running on 3.0.3 (actually is Xen 3.1.2 with 3.0.3 dom0 tools on el5.5, check your "xm dmesg" output). Anyhow, it's been stable "enough" for me, currently on version 0.10.0.142 of the GPL PV drivers. Actually I don't use it for my production stuff either, but since in my experience it's significantly faster than other virt platforms, we use it where I feel is appropriate. Here's my one exception: one of my boxes (was XP) would keep blue-screening (irql_not_less_than_or_equal (sp?) ), another one of our sysadmins located it to be an issue with the on-demand/live virus scanner software; switched to a different product and the problem went away. I also had another different XP box have the same error for awhile back in early 2009 and that arrived and went away with upgrades of xen on the host. But in the last two years I've never had issue with Server 2003, or (very limited use) 2008. 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
[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
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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 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 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: [] __down_read+0x7a/0x92 Oct 15 07:57:44 ha7 kernel: [] :dlm:dlm_user_request+0x2d/0x175 Oct 15 07:57:44 ha7 kernel: [] deactivate_task+0x28/0x5f Oct 15 07:57:44 ha7 kernel: [] file_has_perm+0x94/0xa3 Oct 15 07:57:44 ha7 kernel: [] :dlm:device_write+0x2f5/0x5e5 Oct 15 07:57:44 ha7 kernel: [] vfs_write+0xce/0x174 Oct 15 07:57:44 ha7 kernel: [] recalc_sigpending+0xe/0x25 Oct 15 07:57:44 ha7 kernel: [] sys_write+0x45/0x6e Oct 15 07:57:44 ha7 kernel: [] 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 Fri, Oct 15, 2010 at 2:57 AM, Poh Yong Hwang 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 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] Can I install Slackware 13.1 as Xen-Guest?
On Jul 26, 2010, at 7:05 AM, Wendy William wrote:
> No error message. The installation show Slackware boot: press ENTER or F2.
> But when I press ENTER or F2 then nothing happend.
>
> I am using Slackware 13.1 32 bit.
I haven't done this since Slackware 11 for a client, but at the time the
Slackware kernels didn't have the Xen guest extension. So I was never able to
complete an emulated CD-based installation ... [1]
So, the last time I ran Slackware as a domu I think I ran pkgtool with a
different target dest: to the domu disk mounted in the dom0. Like installing
Debian/Ubuntu with debootstrap. And then I booted off a custom-built kernel
located the host (no pygrub). ... except I can't remember how I would have
gotten pkgtool on my non-Slackware dom0 ... it's also possible that I did such
an installation on a loop-mounted disk image on a Slackware installation, and
then copied that image over and dd-ed it to my domu's disk. (Even tarballing
it over would work fine if you have the right options, though I suspect I went
the dd route.)
YMMV since it's been years since I did this, it but could give you some other
avenues to try besides CD-based install.
Eric
[1] I typically avoid emulated CD installs anyhow because they are tedious
(hard to automate/script). I prefer some sort of installation from the host:
debootstrap, Gentoo untar/chroot. I guess it breaks down with CentOS guests
where I don't exactly do this: instead of using a CD, I boot to
os/$arch/images/xen/{vmlinuz,initrd.img} with kickstart options. I think there
was some tool more like debootstrap for this I looked at several years ago
(called "rope"?) but it was unmaintained at the time.
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Re: [CentOS-virt] Windows Xen VM's have high guest CPU usage and poor performance
The install worked beautifully except that my VM now has an ip assigned of 192.168.122.186 which I'm guessing is in relation to virbr0 which is 192.168.122.1 on the host (and subsequently has no internet connectivity). Is it possible for me to pass through to my network like before so my VM can have an ip on my local network? Unless you specify a bridge in the xen conf file, it uses the first one it finds alphabetically, I believe. Do you use virbr0 for anything else? As an easy way of making sure xenbr0 is used, I removed the file /etc/libvirt/qemu/networks/autostart/default.xml which was auto-starting this DHCP (and NATted?) bridge, and I only was using direct access. But you can also make it explicit on the interface line, one of my HVM VMs has the following: vif = [ 'mac=00:16:3e:0a:4c:d2, bridge=xenbr0' ] Eric signature.asc Description: OpenPGP digital signature ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] xendomains not autostarting
On Mon, Nov 30, 2009 at 11:18 AM, Ben M. wrote: > Thanks, you gave me some solid points to check that I hadn't fully and I > think I know a little more. > > My chkconfig run level 2 was on, but runlevel was at "N 3". I toggled > off, rebooted, no difference. Toggled on and off for the rest of the > checklist. (p.s. on next most recent post: it's not about the "list", it's that your email client contains a reference to the thread which other mail clients use to present the thread in some manner--a tree or such. "All other lists you have been on" would have acted the same way, you just may not have realized as we all have different email clients.) I didn't go into detail about what I was trying to point out about the runlevels, which I think may have led you astray a bit. Being in runlevel 3 means it wouldn't matter whether xendomains is set to start when in 2. I only brought it up because by default xendomains doesn't start in 2, so *if* you were starting in 2 it wouldn't start then. As you're apparently running in 3 (the default), "toggling" the setting for 2 was a bit of a red herring. > Everything checked out except for XENDOMAINS_RESTORE=true > which is default. I set it to false, toggled the runlevel 2 for a couple > of reboot checks. No joy, but ... > > Oddly I am getting Saves, even though DESTROY is explicitly set in the > vm's conf to all circumstances: "destroy" in this context is your setting for what happens when the domain stops *on its own accord*. You still get saves if you shut down the dom0 and the xendomains script goes around and saves all the running domains (assuming it is configured to do that). > name = 'v22c54' > uuid = 'a3199faf-edb4-42e5-bea1-01f2df77a47f' > maxmem = 512 > memory = 512 > vcpus = 1 > bootloader = '/usr/bin/pygrub' > on_poweroff = 'destroy' > on_reboot = 'destroy' > on_crash = 'destroy' > vfb = [ 'type=vnc,vncunused=1,keymap=en-us' ] > # note selinux is off now, but the privileges are set correctly > disk = [ 'tap:aio:/var/lib/xen/images/vms/v22c54,xvda,w' ] > vif = [ 'mac=00:16:36:41:76:ae,bridge=xenbr1' ] > > I then slapped it around a bit and another quirk appeared. > > From a fresh boot, I then manually started xendomains service. v22c54 > comes up. I did an xm shut and it reported it shut, nothing in the Save > folder. However, check this out: > > [r...@river22 ~]# service xendomains start > Starting auto Xen domains: v22c54[done] [ OK ] > [r...@river22 ~]# xm list > Name ID Mem(MiB) VCPUs State Time(s) > Domain-0 0 1024 2 r- 24.7 > v22c54 1 511 1 r- 9.0 > > [r...@river22 ~]# xm shutdown v22c54 > (no echo) > > (I then tried to bring it back up, it balks, its not there and I see a > boot_kernel.random and a boot_ramdisk.random come up in /var/lib/xen) > > [r...@river22 ~]# xm create v22c54 > Using config file "/etc/xen/v22c54". > Error: VM name 'v22c54' already in use by domain 1 > > (it isn't there) > [r...@river22 ~]# xm list > Name ID Mem(MiB) VCPUs State Time(s) > Domain-0 0 1024 2 r- 29.7 > [r...@river22 ~]# xm shutdown v22c54 > Error: Domain 'v22c54' does not exist. > Usage: xm shutdown [-waRH] > > Shutdown a domain. > [r...@river22 ~]# xm list > Name ID Mem(MiB) VCPUs State Time(s) > Domain-0 0 1024 2 r- 29.9 > > I certainly like to know why things glitch and don't mind seeing this > through a little further, but I am beginning to wonder if I should just > backup the domU's and try a fresh installation. > > Is it possible I am running into a naming convention on these domUs? > > My first 3 chars help me determine on which host the virtual machine was > originally created. Likely just a timing issue if that was the order you ran the commands in. xm shutdown tells the guest to shutdown, it doesn't instantly destroy it. This can take awhile dependent on what your guest needs to do. If xm create told you it was still in use, it probably was still shutting down. It then probably finished shutting down and was gone when you ran xm list. The only thing that would be alarming is if you ran xm list *first* and didn't see the domain and then ran xm create and it told you it was in use. Typically if I need to hard-cycle the host (config file changes) I shut down a guest from the guest OS, watch xm list until it goes away, and then run xm create. The other thing I meant to suggest in my first email would be modifying (make a backup first) the xendomains start() function to append `date` to some random file in /tmp or similar. That would help target whether the error is that the xendomains script isn't running (OS configuration issue) or that it is running but not starting the domain (something more to do with xen configuration). Anyways, these are just so
Re: [CentOS-virt] xendomains not autostarting
On Nov 30, 2009, at 8:26 AM, Ben M. wrote:
> I have been scratching my head on this for days. Xendomains services
> just doesn't want to start at boot it seems, so I don't get my
> auto-domU's up without "service xendomains start" and the all start.
>
> chkconfig looks correct, I have checked xm dmesg, dmesg, turned off
> selinux and the only "clue" I have is that the xend.log startup looks
> different than a fairly similar machine and I don't quite understand
> what it might be saying. Is dom0 crashing and restarting at machine bootup?
>
> I have only one domU in ../auto to keep this simpler, its name is
> "v22c54" and I have one other anomaly: smartd is also not starting on
> services boot up but apparently runs fine with a manual command.
I'm guessing you covered this ("chkconfig looks correct") but you didn't change
to a different runlevel like 2 did you?
[r...@xen1 ~]# chkconfig --list xendomains
xendomains 0:off 1:off 2:off 3:on4:on5:on6:off
[r...@xen1 ~]# grep :initdefault /etc/inittab
id:3:initdefault:
[r...@xen1 ~]# runlevel
N 3
Also, I'm not too familiar with it, but if you're not shutting your domains off
before reboot there may be something awry with the save/restore functionality.
Personally I have this disabled so I can't speak to whether it would create the
symptom you have, but it might be something to try. I have:
[r...@xen1 ~]# grep "^[^#]" /etc/sysconfig/xendomains
XENDOMAINS_SYSRQ=""
XENDOMAINS_USLEEP=10
XENDOMAINS_CREATE_USLEEP=500
XENDOMAINS_MIGRATE=""
XENDOMAINS_SAVE=""
XENDOMAINS_SHUTDOWN="--halt --wait"
XENDOMAINS_SHUTDOWN_ALL="--all --halt --wait"
XENDOMAINS_RESTORE=false
XENDOMAINS_AUTO=/etc/xen/auto
XENDOMAINS_AUTO_ONLY=false
XENDOMAINS_STOP_MAXWAIT=300
Eric
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Re: [CentOS-virt] Migrating from KVM to XEN - kernel panic
On Nov 6, 2009, at 11:49 AM, Christopher Hunt wrote: [...] > [r...@vmm03-xen xen]# cat /etc/xen/guest02 > # Automatically generated xen config file > name = "guest02" > memory = "1024" > disk = [ 'phy:/dev/VMM01-KVMvg00/guest02,xvda,w', ] > vif = [ 'mac=00:16:3e:5c:f1:dd, bridge=xenbr0', ] > vfb = ["type=vnc,vncunused=1"] > #bootloader="/usr/bin/pygrub" > kernel = "/boot/vmlinuz-2.6.18-164.6.1.el5xen" > ramdisk = "/boot/initrd-2.6.18-164.6.1.el5xen.img" > vcpus=1 > on_reboot = 'restart' > on_crash= 'restart' > #root = "/dev/VMM01-KVMvg00/c5root00 ro" > #extra = "single selinux=0" > extra = "ro" [...] > [r...@guest02 ~]# cat /etc/grub.conf > # grub.conf generated by anaconda > # > # Note that you do not have to rerun grub after making changes to > this file > # NOTICE: You have a /boot partition. This means that > # all kernel and initrd paths are relative to /boot/, eg. > # root (hd0,0) > # kernel /vmlinuz-version ro root=/dev/vg00/root divider=10 > notsc > # initrd /initrd-version.img > #boot=/dev/vda > default=0 > timeout=5 > splashimage=(hd0,0)/grub/splash.xpm.gz > hiddenmenu > title CentOS (2.6.18-164.el5) > root (hd0,0) > kernel /vmlinuz-2.6.18-164.el5 ro root=/dev/vg00/root > divider=10 notsc > initrd /initrd-2.6.18-164.el5.img Couple thoughts: /etc/grub.conf on the guest is actually irrelevant with the xen config you gave as you're not using pygrub, but are using a specified dom0 kernel/initrd (what pygrub does is use grub on the domU to use the domU's kernel/initrd). Now, this would be fine, but you'll likely run into issues with not having appropriate modules installed for that kernel; you might be able to boot without any modules (lots of errors certainly though) but it depends. My recommendation is usually to use pygrub along with installing the right domU kernel-xen. You might be able to do this, even if you do not have access to the KVM host any longer, by using "kpartx" to create a block device for the partition inside the lv, mounting it in the dom0, and then using some alternate install root for rpm/yum (not sure what the option is offhand). Lastly, to help with debugging: it's been a while since I had to dive into this, and I was using Gentoo at the time, but it use to be there was a difference between /dev/tty0 and /dev/console with Xen; you use to have to change your inittab to have the getty load on /dev/ console. Oh, actually, looking at my CentOS boxes now, it seems that kudzu rewrote /etc/inittab to start a getty on "xvc0" (see below). Anyhow, what I'm reasoning is that perhaps you're not seeing errors on "xm console" because you either need to pass/append "console=xvc0" on your kernel command line (xen config "extra" param I think) *or* update your getty line in /etc/inittab (again, by using kpartx if you don't have access to the old, running machine). Cheers, Eric - # Run gettys in standard runlevels co:2345:respawn:/sbin/agetty xvc0 9600 vt100-nav #1:2345:respawn:/sbin/mingetty tty1 #2:2345:respawn:/sbin/mingetty tty2 #3:2345:respawn:/sbin/mingetty tty3 #4:2345:respawn:/sbin/mingetty tty4 #5:2345:respawn:/sbin/mingetty tty5 #6:2345:respawn:/sbin/mingetty tty6 ___ 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. 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 ('') 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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