virt July 2011

virt@lists.centos.org

34 participants
20 discussions

how to add file-based disk space to a guest
by thomas veymont 31 Oct '11

31 Oct '11

hi there, I'm following these documentations to add a file-based disk volume to a KVM guest under Centos 6.0 : http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Virtualiz… as instructed, I created a "pool" then a "volume", file-based, e.g : mkdir /mnt/raid/kvm_pool1 virsh # pool-define-as pool1 dir - - - - "/mnt/raid/kvm_pool1" virsh # pool-autostart pool1 virsh # vol-create-as pool1 volume1 20G --allocation 15G --format qcow2 now I want to associate "volume1" to my guest OS. Following this doc: http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Virtualiz… - why does this ask me to create a file with "dd" ? it's already been created before with the virsh pool commands, isn't it? Seems to me I'm bypassing the libvirt/virsh layer if I do that. - after that, the doc tells me to do some stuff with guest XML files. Is'nt there some specific commands provided by virsh to associate a managed Pool to a managed Guest ? - in this case, should I use the virsh "attach-disk" command ? thanks. -- Tom

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Suggestions to improve this minimal kickstart config for CentOS 6?
by Kartik Subbarao 01 Aug '11

01 Aug '11

I've come up with the following kickstart config (see below) for deploying a minimal CentOS 6 VM. It takes about 460MB. I'm assuming that all of the -firmware RPMs aren't needed for a VM installation, so I removed them. Also removed as many selinux packages as possible since I don't need that. I was wondering whether anyone could offer any further suggestions on minimizing the disk usage of the VM image. Also, I wanted to ask whether it might make sense to post this type of configuration to the CentOS wiki, possibly linked from the following page: http://wiki.centos.org/TipsAndTricks/KickStart This might make it easy for people who are building VMs for reference. Thanks, -Kartik ======== lang en_US.UTF-8 keyboard us timezone America/New_York auth --useshadow --passalgo=md5 selinux --disabled firewall --disabled zerombr bootloader --location=mbr network --bootproto=dhcp --device=eth0 --onboot=on services --enabled=network rootpw admin123 clearpart --all --initlabel part / --asprimary --fstype="ext3" --grow --maxsize=1000 --size=1 # Repositories url --url="http://mirrors.kernel.org/centos/6.0/os/x86_64/" %packages --excludedocs --nobase --instLangs=en @Core %post rpm -e $(rpm -qa |grep -i firmware) yum -y remove audit authconfig checkpolicy libsemanage libselinux-utils policycoreutils selinux-policy selinux-policy-targeted rm -rf /etc/selinux/targeted rpm -e --nodeps redhat-logos %end

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idle C6 guest on C6 host constantly using 10% cpu
by Dennis Jacobfeuerborn 29 Jul '11

29 Jul '11

Hi, I'm playing around with KVM virtualization on Centos 6 and I noticed then after I created a regular minimal install in a VM this guest will constantly use 10% of the cpu when idle. Any ideas what the problem might be? Regards, Dennis

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Snapshot error "command savevm not found"
by Trey Dockendorf 29 Jul '11

29 Jul '11

Attempting to take snapshots of VM using virsh with the following command, # virsh -c qemu:///system snapshot-create CentOS6-x86-001 Results in the following error, error: internal error unable to execute QEMU command 'savevm': The command savevm has not been found The VM's virtual disks are qcow2. Below is the XML file for this vm ------------ <domain type='kvm' id='6'> <name>CentOS6-x86-001</name> <uuid>050fb9d8-0b9a-48b9-a432-16eec57a9e8f</uuid> <memory>1024000</memory> <currentMemory>1024000</currentMemory> <vcpu>1</vcpu> <os> <type arch='x86_64' machine='rhel6.0.0'>hvm</type> <boot dev='hd'/> </os> <features> <acpi/> <apic/> <pae/> </features> <clock offset='utc'/> <on_poweroff>destroy</on_poweroff> <on_reboot>restart</on_reboot> <on_crash>restart</on_crash> <devices> <emulator>/usr/libexec/qemu-kvm</emulator> <disk type='file' device='disk'> <driver name='qemu' type='qcow2' cache='none'/> <source file='/vmstore/CentOS6-x86-001/CentOS6-x86-001_sys.qcow2'/> <target dev='vda' bus='virtio'/> <alias name='virtio-disk0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/> </disk> <disk type='file' device='cdrom'> <driver name='qemu' type='raw'/> <target dev='hdc' bus='ide'/> <readonly/> <alias name='ide0-1-0'/> <address type='drive' controller='0' bus='1' unit='0'/> </disk> <disk type='file' device='disk'> <driver name='qemu' type='qcow2'/> <source file='/vmstore/CentOS6-x86-001/CentOS6-x86-001_var.img'/> <target dev='vdb' bus='virtio'/> <alias name='virtio-disk1'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/> </disk> <controller type='ide' index='0'> <alias name='ide0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/> </controller> <interface type='bridge'> <mac address='52:54:00:4d:74:c7'/> <source bridge='br0'/> <target dev='vnet0'/> <model type='virtio'/> <alias name='net0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> </interface> <serial type='pty'> <source path='/dev/pts/1'/> <target port='0'/> <alias name='serial0'/> </serial> <console type='pty' tty='/dev/pts/1'> <source path='/dev/pts/1'/> <target port='0'/> <alias name='serial0'/> </console> <input type='tablet' bus='usb'> <alias name='input0'/> </input> <input type='mouse' bus='ps2'/> <graphics type='vnc' port='5900' autoport='yes'/> <video> <model type='cirrus' vram='9216' heads='1'/> <alias name='video0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/> </video> <memballoon model='virtio'> <alias name='balloon0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/> </memballoon> </devices> <seclabel type='dynamic' model='selinux'> <label>system_u:system_r:svirt_t:s0:c292,c580</label> <imagelabel>system_u:object_r:svirt_image_t:s0:c292,c580</imagelabel> </seclabel> </domain> ------------ This is my first attempt at snapshots with KVM after migrating from ESXi, so if there's a better method please let me know. Thanks - Trey

1 0

Send magic-sysrq from virtual serial console?
by David Knierim 28 Jul '11

28 Jul '11

I am using CentOS 5.6 as a KVM host. My guests are running CentOS 5.6 with the only console being a virtual serial console. The guests are configured so magic-sysreq can be used to debug kernel issues. However, in order to send magic-sysrq from a serial port, I need to send a break. How does one send a break on the virtual console serial port provided by KVM/libvirt to guests? Thanks, David

1 0

Xen dom0 support for CentOS-6
by Karanbir Singh 28 Jul '11

28 Jul '11

hi guys, This conversation seems to come up often; people are still quite keen on having dom0 support for CentOS-6; If we can answer a few questions, we can move that issue forward a bit : - What do we need to do in order to make that happen ? - What code needs to show up in CentOS/Extras or Plus ? - and is anyone willing to take ownership of handing this ? Regards, - KB

2 1

(no subject)
by Grant McWilliams 28 Jul '11

28 Jul '11

http://nichejunky.com/google.php

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Re: [CentOS-virt] [Rocks-Discuss] Virtualizing RockCluster 5.3
by Nehemiah Dacres 27 Jul '11

27 Jul '11

is there a way to virtualize rocks5.2 on rocks5.4? I have been trying to and the gecko based install menu keeps failing. The error is a http 404 when looking for the release notes to display. any Idea of what causes that? I had that happen last time I tried to install rocks 5.2 on bare metal. The only notable thing about my network is that its on a 255.255.254.0 subnet mask. I can reserve its ip and everything. On Tue, Jul 13, 2010 at 12:58 AM, Jon Forrest <jlforrest(a)berkeley.edu>wrote: > On 7/12/2010 9:02 PM, Poh Yang Ming wrote: > >> Hi! >> >> I am trying to virtualize Rockcluster 5.3 for various testing with >> limited hardware. I have manage to get the headnode up in qemu >> (fedora13, x86_64). However, I am experiencing some issue to connect >> the headnode to the compute node. >> >> Has anyone done virtualization of rockcluster with qemu or has a >> better virtualization tools that is known to work? >> > > One possibility is to use VirtualBox. Take a look > at the method I posted about a couple of days ago > to see how I did it. > > Cordially, > -- > Jon Forrest > Research Computing Support > College of Chemistry > 173 Tan Hall > University of California Berkeley > Berkeley, CA > 94720-1460 > 510-643-1032 > jlforrest(a)berkeley.edu > > -- Nehemiah I. Dacres System Administrator Advanced Technology Group Saint Louis University

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Re: [CentOS-virt] Suggestions to improve this minimal kickstart config for CentOS 6?
by Manuel Wolfshant 22 Jul '11

22 Jul '11

On 07/20/2011 04:48 PM, Kartik Subbarao wrote: > On 07/19/2011 05:36 PM, Manuel Wolfshant wrote: >> Try the attached ks. It installs around 180 packages. libselinux-utils >> is in because I find it mandatory to be able to modify the selinux >> configuration of an existing system. > > Thanks for the info. I created a VM with this config and it took up > about 512MB of disk space, which is higher than the kickstart file > that I posted (about 460MB). you removed selinux and also used rpm -e --nodeps which I would never promote (even if I also use on occasions). ditch from my list the packages which install firmware and you'll end up at roughly the same size as yours. anyway my target was never minimal space on disk (today even CFs and SSD are several times larger than what the ks installs ) but minimal number of packages while still maintaining out of the box all the proper functionality ( or at least my vision on it), including for servers with real storage behind them ( brocade, etc ). and I emphasize again: including selinux tools. > I'm running x86_64 so I'll probably see different sizes than your > system which appears to be i686. my ks works on both, just adjust the repository used for install > > In any event, thanks for taking the time to post your kickstart file. > It helps me validate that what I have is reasonably minimal, that I'm > probably not missing any major sources of size reductions. welcome

3 10

Many Xen related bugfixes and enhancements in RHEL 5.7 / CentOS 5.7
by Pasi Kärkkäinen 21 Jul '11

21 Jul '11

Hello, RHEL 5.7 has just been released, so here are some interesting Xen related bugfixes and enhancements in el5.7: Overview of Xen update in 5.7: http://rhn.redhat.com/errata/RHBA-2011-1070.html Technical notes about Xen changes in 5.7: https://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5/html/5.7_Tech… Also kernel has a lot of fixes and updates: http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5/html/5.7_Techn… Cheers, -- Pasi

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virt July 2011