virt January 2016

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24 participants
21 discussions

Updated centos-release-xen packages (fixes missing initrd issue on upgrade)
by George Dunlap 13 Feb '16

13 Feb '16

I've pushed an update to the centos-release-xen package, centos-release-xen-7-12.el6, to centos-virt-xen-testing, which should fix the "missing initrd" issue people have been seeing. Please test and see if it fixes your issue (and that it makes no other issues). If everything works well, I'll get it pushed to centos-extras. Thanks, -George

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CentOS 6 Virt SIG Xen 4.6 packages available in centos-virt-xen-testing
by George Dunlap 10 Feb '16

10 Feb '16

As mentioned yesterday, Xen 4.6 packages are now available for testing. These also include an update to libvirt 1.3.0, in line with what's available for CentOS 7. Please test, particularly the upgrade if you can, and report any problems here. To upgrade: yum update --enablerepo=centos-virt-xen-testing To install from scratch: * Install centos-release-xen from centos-extras yum install centos-release-xen * Update to get the new kernel: yum update * Install the Xen packages from the centos-virt-xen-testing repo: yum install --enablerepo=centos-virt-xen-testing xen Keep in mind that there is still a bug in the upstream CentOS new-kernel script which for some people consistently fails to add an "initird" line to the Xen boot stanza. Check /boot/grub/grub.conf; the Xen stanza should look something like this: title CentOS (3.18.21-17.el6.x86_64) root (hd0,0) kernel /xen.gz dom0_mem=1024M,max:1024M cpuinfo com1=115200,8n1 console=com1,tty loglvl=all guest_loglvl=all module /vmlinuz-3.18.21-17.el6.x86_64 ro root=/dev/mapper/VolGroup-lv_root rd_NO_LUKS LANG=en_US.UTF-8 rd_NO_MD rd_LVM_LV=VolGroup/lv_swap SYSFONT=latarcyrheb-sun16 crashkernel=auto rd_LVM_LV=VolGroup/lv_root KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet module /initramfs-3.18.21-17.el6.x86_64.img -George

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Mouse and display issues with Windows 10 guest
by Robert Nichols 07 Feb '16

07 Feb '16

Anyone managed to get a Windows 10 guest running well under qemu/kvm? I can get it up and running, but there is a major issue with losing use of the mouse, plus my display resolution is stuck at 1024x768. The mouse will work for a short time (a few seconds to a few minutes), but then stops responding. That's with the mouse coming in as the recommended QEMU tablet device. I can assign a USB mouse to the guest as a USB host device, but it also stops responding after a short time. At least with the USB mouse I can remove it from the guest and then reassign it again. That gives me use of the mouse, but again only for a short time. Trying run Windows 10 from just a keyboard is an exercise in frustration. I can't get Windows 10 to believe that any screen resolution besides 1024x768 is available. That's the case both with VNC/vga and Spice/qxl. This is in contrast with Windows 7, which offers a good selection of resolutions with VNC/vga. Any suggestions or success reports would be appreciated. -- Bob Nichols "NOSPAM" is really part of my email address. Do NOT delete it.

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When will CentOS 7.1 become available as an AWS AMI?
by Peter Weissbrod 02 Feb '16

02 Feb '16

I am in need of some AWS instances of this version. There are "community" instances of 7.1 but I would strongly prefer an official release from CentOS team over trusting my base image to an unknown publisher. Is there any plan/projection of when CentOS will publish 7.1 to the AWS marketplace?

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hoping to reschedule SIG meetings to Tuesdays 1500 UTC
by Lokesh Mandvekar 26 Jan '16

26 Jan '16

I can't make it to the current schedule for alternate Tuesday 1400 UTC meetings. I was hoping we could reschedule it to 1500 UTC on the same Tuesdays instead, or any other slot which could work for all. What do other members think? -- Lokesh Freenode: lsm5 GPG: 0xC7C3A0DD

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LVM mirror database to ramdisk
by Ed Heron 24 Jan '16

24 Jan '16

I'm still running CentOS 5 with Xen. We recently replaced a virtual host system board with an Intel S1400FP4, so the host went from a 4 core Xeon with 32G RAM to a 6 core Xeon with 48G RAM, max 96G. The drives are SSD. I was recently asked to move an InterBase server from Windows 7 to Windows Server. The database is 30G. I'm speculating that if I put the database on a 35G virtual disk and mirror it to a 35G RAM disk, the speed of database access might improve. I use local LVM for my virtual disks with DRBD on top to mirror the disk to a backup server. If I change grub.conf to increase RAM disk size and increase host RAM, I could create a 35G RAM disk. I'd modify rc.local to add pvcreate /dev/ramdisk vgextend vg /dev/ramdisk lvconvert -m 1 --corelog vg/lv_database /dev/ramdisk Even with lv_database being 35G, it doesn't take long to activate the mirror. I haven't decided where to put the commands to turn off the lvm mirror. lvconvert -m 0 vg/lv_database vgreduce vg /dev/ramdisk pvremove /dev/ramdisk I haven't put this in real world use, yet. On it's face, this might speed up database access. Would we expect it to speed up database access in real world use? Should I document the process so others could know how to do this? I realize new documentation for CentOS 5 virtualization would be considered obsolete before I wrote it but I'm expecting to test CentOS 7 virtualization in the next few months and, when I am comfortable, I'd upgrade my 18 virtual hosts. I would update the documentation, at that time, as well.

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Hostname inside lxc container
by C. L. Martinez 22 Jan '16

22 Jan '16

Hi all, I have installed a CentOS6 lxc guest under a Debian 8.x LXC host. All it is working ok but I can't change the hostname for the centos6 lxc container (it is using the same hostname from Debian host). I have modifyed HOSTNAME under /etc/sysconfig/network and /etc/hosts file, but it doesn't works. Do I need to change anything else?? Thanks.

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DomU Guests not shutting down nicely when Dom0 Hypervisor shuts down
by Francis Greaves 21 Jan '16

21 Jan '16

I am using Xen 4.6.0-8.el7 on CentOS 7 with 3 Linux DomUs. I did have Xen 4.? on CentOS 6.5 on my previous system. I installed using yum install centos-release-xen. On shutting down the Hypervisor it used to wait for the DomUs to shut down gracefully (one can take a minute or more), then on starting up again it would restart the DomUs, all nice and controlled. For some reason the DomUs (CentOS or Ubuntu servers) are not shutting down nicely when the Hypervisor is shutdown, and not restarting. I have the cfg files in /etc/xen/auto so they should start up. If I forget to shut down the DomU guests then the shutdown hangs. I am running this on a Dell Poweredge T430 by the way. Any ideas why, and how to cure this?

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Re: [CentOS-virt] CentOS 6 Virt SIG Xen 4.6 packages available in centos-virt-xen-testing
by President 21 Jan '16

21 Jan '16

My .02 is to stay the course. As a server admin, I want to be able to type things like: yum upgrade php not yum upgrade php55-epel-rpmforge-fancy-package Having to remember all the idiosyncrasies of a system is what causes some type of major failure in the future whenever (1) you forget something or (2) someone else has to pick up the box to adminster. -- Craig Thompson, President Caldwell Global Communications, Inc. +1 (423) 559-5465 caldwellglobal.com -----Original message----- From: George Dunlap <dunlapg(a)umich.edu> Sent: Thursday 21st January 2016 7:32 To: Discussion about the virtualization on CentOS <centos-virt(a)centos.org> Subject: Re: [CentOS-virt] CentOS 6 Virt SIG Xen 4.6 packages available in centos-virt-xen-testing On Thu, Jan 21, 2016 at 12:01 PM, Peter <peter(a)pajamian.dhs.org> wrote: > On 15/01/16 05:57, George Dunlap wrote: >> As mentioned yesterday, Xen 4.6 packages are now available for >> testing. These also include an update to libvirt 1.3.0, in line with >> what's available for CentOS 7. Please test, particularly the upgrade >> if you can, and report any problems here. > > Per conversation in IRC, Xen 4.6 no longer includes xend and therefore > no longer has the "xm" command. This is problematic for people who may > be using xm in various scripts on their host (such as home-brewed backup > scripts). > > I think it's a bad idea to break this functionality without warning by > allowing a simple "yum update" to remove it. You will take a lot of > people by surprise and cause such scripts to stop working, if people are > running yum cron the situation becomes even worse. Thanks, PJ, for your input. Just to be clear: 1. In the Xen 4.4 packages (first released October 2014), xend was disabled by default; so anyone using xend at the moment has already manually intervened to enable deprecated functionality 2. In 4.4, the first time xm was executed, it printed this warning: --- xend is deprecated and scheduled for removal. Please migrate to another toolstack ASAP. See http://wiki.xen.org/wiki/Choice_of_Toolstacks for information on other alternatives, including xl which is designed to be a drop in replacement for xm (http://wiki.xen.org/wiki/XL). --- 3. ...and on every subsequent invocation, it printed this warning: "WARNING: xend/xm is deprecated" I think this constitutes "warning" that the functionality was going to break at some point. :-) Also, in most cases "s/xm/xl/g;" Just Works; most people have reported that changing from xm -> xl was pretty painless. So this isn't like upgrading from Python 2 to Python 3 (or QT 4 to 5, or...). > I think that due to this lack of backwards compatibility with Xen 4.4 > and earlier versions it would be a good idea to not force the upgrade on > people who are not wary of it. I propose that the new packages carry > the name "xen46" and they purposefully conflict with the old "xen" > packages. That will require people to take positive action to do the > upgrade and hence avoid breaking systems unintentionally. This would avoid breaking things for people still using xm, which certainly has some value. However it has some costs: * The packages between C6 and C7 will now be slightly different, increasing the maintenance burden. This is not only in the spec file, but also in all the associated scripting machinery for managing packages in the CBS and smoke-testing packages before pushing them publicly. * Instructions for installing Xen are now differend between C6 and C7, and slightly more complicated, as they have to explain about Xen 4.6 vs alternatives. * Users who have heeded the warning and switched to xl will have to make an extra effort to switch to Xen 4.6. If they don't follow centos-virt, they may not notice that there's a new package to upgrade to. I'm a developer, not a server admin, so I can't gauge how important this issue is. Before making such a change, I'd like to hear opinions from other people in the community about how important (or not) it is to avoid breaking xm, given the ample warning (>1 year) users have had. On the other hand, explicitly moving to a "xen${VER}" (both for C6 and C7) would make it simpler for people to step up and maintain older versions in parallel if anybody wanted to do so. Thanks again, Peter, for bringing this up. Peace, -George _______________________________________________ CentOS-virt mailing list CentOS-virt(a)centos.org https://lists.centos.org/mailman/listinfo/centos-virt

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Re: [CentOS-virt] DomU Guests not shutting down nicely when Dom0 Hypervisor shuts down
by Keith Roberts 21 Jan '16

21 Jan '16

Hi Francis. Personally I would gracefully shutdown all the VM’s first, before attempting to shutdown the xen hypervisor. Are you getting any fsck errors when restarting those VM’s? Kind Regards, Keith On 21 Jan 2016, at 08:48, Francis Greaves <francis(a)choughs.net> wrote: > I am using Xen 4.6.0-8.el7 on CentOS 7 with 3 Linux DomUs. I did have Xen 4.? on CentOS 6.5 on my previous system. I installed using yum install centos-release-xen. > On shutting down the Hypervisor it used to wait for the DomUs to shut down gracefully (one can take a minute or more), then on starting up again it would restart the DomUs, all nice and controlled. > For some reason the DomUs (CentOS or Ubuntu servers) are not shutting down nicely when the Hypervisor is shutdown, and not restarting. I have the cfg files in /etc/xen/auto so they should start up. > If I forget to shut down the DomU guests then the shutdown hangs. > I am running this on a Dell Poweredge T430 by the way. > Any ideas why, and how to cure this? > _______________________________________________ > CentOS-virt mailing list > CentOS-virt(a)centos.org > https://lists.centos.org/mailman/listinfo/centos-virt

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virt January 2016