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1612 discussions

XEN or KVM - performance/stability/security?
by Rafał Radecki 21 Apr '12

21 Apr '12

Hi all. I am currently building a small test cloud based on Eucalyptus 2.0.3 and CentOS 5.8 x64. I have a choice which hypervisor to use: KVM or XEN. KVM is the default in CentOS 6 but I have read also many good things (for example PV guest machines, isolation between Dom0 and DomU) about XEN. Key factors from my opint of view are: - stability (which one runs more smoothly on CentOS?) - performance (XEN PV/HVM(with or without pv drivers) vs KVM HVM(with or without pv drivers)) - security Could you share your experience in these areas? Best regards, Rafal Radecki.

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NIC binding on host and pass through to guests
by Tommy Pham 06 Apr '12

06 Apr '12

Hi, I've just joined the list because of questionnaire in the forum [1]. The hardware is AMD-V(IOMMU) capable and is enabled in the BIOS with 3 NICs. I currently have host Windows 2008 R2 installed but binds (network services and protocols) on NIC3 only. My guests on VMWare workstation (has bridged network service bound on all 3 NIC) has bridged 3 NICs for the guests where NIC1 is WAN, NIC2 is LAN1, and NIC3 is LAN2. One guest have access to all 3 NICs. Other guests would only have access to either NIC2 or NIC3. Is it possible to duplicate this in CentOS 6.2 (minimal install preferred) with open source virtualization (qemu-kvm/libvirt ?) ? I think I need to install the bridge-utils package. Do I need to install the ebtables too? Thanks, Tommy [1] https://www.centos.org/modules/newbb/viewtopic.php?topic_id=36785&start=0#f…

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Um convite especial
by Gilberto Ferreira 06 Apr '12

06 Apr '12

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Re: [CentOS-virt] CentOS-virt Digest, Vol 55, Issue 10
by Su Zhang 25 Mar '12

25 Mar '12

On Sat, Mar 24, 2012 at 11:00 AM, <centos-virt-request(a)centos.org> wrote: > Send CentOS-virt mailing list submissions to > centos-virt(a)centos.org > > To subscribe or unsubscribe via the World Wide Web, visit > http://lists.centos.org/mailman/listinfo/centos-virt > or, via email, send a message with subject or body 'help' to > centos-virt-request(a)centos.org > > You can reach the person managing the list at > centos-virt-owner(a)centos.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of CentOS-virt digest..." > > > Today's Topics: > > 1. Re: CentOS domU cannot boot up (Alexander Dalloz) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sat, 24 Mar 2012 16:22:44 +0100 > From: Alexander Dalloz <ad+lists(a)uni-x.org> > Subject: Re: [CentOS-virt] CentOS domU cannot boot up > To: Discussion about the virtualization on CentOS > <centos-virt(a)centos.org> > Message-ID: <4F6DE6C4.3080802(a)uni-x.org> > Content-Type: text/plain; charset=ISO-8859-1 > > Am 24.03.2012 02:40, schrieb Su Zhang: > > Hello community, > > > > I encountered an error while installing CentOS as a domU on Xen. The DomU > > paused at boot up > > and failed with messages: "eth0: no IPv6 routers present". I've already > > attached a full screenshot. Can anyone tell me what is happening here? > > > > Thanks, > > The real issue appears to be the message before > > "xvda: unknown partition table" > > You will have to provide details about your system and setup to get help. > > Alexander > > Thanks for pinpointing the issue, here is the command line use for domU > installation: > virt-install -l http://mirror.centos.org/centos/5/os/i386/ -p -n cent5 -r 768 --vcpus=1 --disk=/srv/xen/mailserver.img --graphics vnc,listen=0.0.0.0,port=5901 Here is my kernel info: uname -a Linux XenTester 3.1.0-rc9+ #1 SMP Mon Mar 12 18:18:34 CDT 2012 x86_64 x86_64 x86_64 GNU/Linux Other xen related info: [root@XenTester su]# /etc/init.d/xend start [root@XenTester su]# xm list Name ID Mem VCPUs State Time(s) Domain-0 0 3328 2 r----- 108.6 cent5 768 1 0.0 [root@XenTester su]# xm info host : XenTester release : 3.1.0-rc9+ version : #1 SMP Mon Mar 12 18:18:34 CDT 2012 machine : x86_64 nr_cpus : 2 nr_nodes : 1 cores_per_socket : 2 threads_per_core : 1 cpu_mhz : 2527 hw_caps : bfebfbff:20100800:00000000:00000940:0008e3fd:00000000:00000001:00000000 virt_caps : hvm total_memory : 4026 free_memory : 1171 free_cpus : 0 xen_major : 4 xen_minor : 1 xen_extra : .2 xen_caps : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64 xen_scheduler : credit xen_pagesize : 4096 platform_params : virt_start=0xffff800000000000 xen_changeset : unavailable xen_commandline : cc_compiler : gcc version 4.4.6 20110731 (Red Hat 4.4.6-3) (GCC) cc_compile_by : su cc_compile_domain : (none) cc_compile_date : Mon Mar 12 16:39:43 CDT 2012 xend_config_format : 4 [root@XenTester su]# Anything else info needed? Thanks, > > ------------------------------ > > _______________________________________________ > CentOS-virt mailing list > CentOS-virt(a)centos.org > http://lists.centos.org/mailman/listinfo/centos-virt > > > End of CentOS-virt Digest, Vol 55, Issue 10 > ******************************************* > -- Su Zhang Ph.D Candidate Computing and Information Sciences Kansas State University

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CentOS domU cannot boot up
by Su Zhang 24 Mar '12

24 Mar '12

Hello community, I encountered an error while installing CentOS as a domU on Xen. The DomU paused at boot up and failed with messages: "eth0: no IPv6 routers present". I've already attached a full screenshot. Can anyone tell me what is happening here? Thanks, -- Su Zhang

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Installing Ubuntu 10.04 Lucid guest on Centos 5 using virt-manager
by Dennis Jacobfeuerborn 19 Mar '12

19 Mar '12

Hi, i'm trying to install an Ubuntu Lucid PV guest on a Centos host but I can't seem to find a working installation URL. I tried "http://ftp.ubuntu.com/ubuntu/dists/lucid/main/installer-amd64/" and various subdirectories but I always get the error "Could not find an installable distributio at ...". In the OS Variant box I chose Ubuntu 9.04 as that is the closest to what I'm trying to install. Any idea how this works? Regards, Dennis

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routing problem with domU bridged to two networks
by Peter Peltonen 16 Mar '12

16 Mar '12

As I received no response on the general CentOS list, I'll repost it here as the question is about Xen virtual machine routing. This is my network setup: http://pastebin.com/kyWpTQYU Lets assume my dom0's eth2 public ip is 1.2.3.33 and my dmz network 11.22.33.96/255.255.255.224 . I have created NAT from my LAN with iptables. You can see my /etc/sysconfig/iptables here: http://pastebin.com/1FqSTvPH And this is my dom0 routing table: http://pastebin.com/gNjTFHp5 My goal: To access NFS shares on a (non-virtualized) file server in the LAN network from the domU web server in the DMZ network. What I tried: I attached the domU to both bridges using this Xen config: vif = [ "mac=00:0c:29:de:3a:fe,bridge=xenbr0","mac=00:0C:29:76:19:85,bridge=xenbr1" ] and then created two eth interfaces inside the domU mapping to the MAC addresses above, giving eth1 an IP from the DMZ (11.22.33.111) and giving eth2 an IP from the LAN (192.168.0.12). After this I mounted the NFS share from the file server (192.168.0.2). My problem: If my domU web server is connected to both LAN and DMZ using the two bridges xenbr0 and xenbr1, I can access the NFS share from the domU web server and everything else works as expected, except for one thing -- my workstations in the LAN cannot anymore access the web server: web pages do not open anymore and from the workstations I cannot ping the domU. If the web server domU is only connected to DMZ via xenbr0, the workstations can access it ok. Any advice what I am doing wrong and I could fix my setup? Regards, Peter

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IDE mapping to SATA in virtual guest
by Bradley Leonard 15 Mar '12

15 Mar '12

Hi, I'm trying to map a logical volume (sata) as an ide drive from my centos 6.2 host to my centos 6.2 guest. Here is xml snippet: <disk type='block' device='disk'> <driver name='qemu' type='raw' cache='none' io='native'/> <source dev='/dev/VolGroup02/LogVol00'/> <target dev='hda' bus='ide'/> <address type='drive' controller='0' bus='0' unit='0'/> </disk> Dmesg shows this: sd 0:0:0:0: [sda] 5859368960 512-byte logical blocks: (2.99 TB/2.72 TiB) sd 0:0:0:0: [sda] Write Protect is off sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00 sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA sda: unknown partition table sd 0:0:0:0: [sda] Attached SCSI disk sd 0:0:0:0: Attached scsi generic sg0 type 0 Inside the guest, it shows up as a sata drive: [root@nemedia ~]# sfdisk -l /dev/sda Disk /dev/sda: 364728 cylinders, 255 heads, 63 sectors/track sfdisk: ERROR: sector 0 does not have an msdos signature /dev/sda: unrecognized partition table type No partitions found [root@nemedia ~]# sfdisk -l /dev/hda /dev/hda: No such file or directory sfdisk: cannot open /dev/hda for reading I don't see how this would be a problem except for the fact that no matter what kind of filesystem I try to create on /dev/sda from the guest, I get errors when I try to mount it. No matter what I do, I cannot mount any filesystem from that device inside the guest. Both the cdrom and block device are showing up as scsi devices even though I'm passing them through as ide devices. Am I doing something wrong or am I missing something completely? I've try searching for solution or a hint, but I must not be searching for the right thing. Can anybody provide me some advice or point me somewhere? Thanks in advance. Brad -- Bradley Leonard EMail: bradley at stygianresearch.com Rob - "The hills are alive with the..the..sound of monkeys?" Bucky - "It's in the key of delicious." Life is simple. Humans make it complicated. -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.

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KVM, VLAN and Bridges and bonding
by Baptiste AGASSE 03 Mar '12

03 Mar '12

Hi all, I use CentOS5.x + Xen in production for virtualization. I use it with bridged vlan networks and bonding (active-backup) like that: eth0 eth1 | | ------- | bond0-------bond0.10---------bond0.12 ... | | | | vlanbr10 vlanbr12 dom0 | | ------------- -------------- | | | | | | ... domU1 domU2 domU3 domU4 domU5 domU6 For future hypervisors, i want to implement the same things with CentOS6.x + KVM. In test env i've setup CentOS6.2 + KVM (with last updates) with the same network config, but guest lose network connection very often, and i don't know why. Network config: /etc/sysconfig/network-scripts/ifcfg-bond0.6: DEVICE=bond0.6 BRIDGE=vlanbr6 ONBOOT=yes BOOTPROTO=none VLAN=yes TYPE=Ethernet /etc/sysconfig/network-scripts/ifcfg-vlanbr6: DEVICE=vlanbr6 TYPE=Bridge ONBOOT=yes BOOTPROTO=none DELAY=0 I've installed guest like that (with a lot of retry because of network loss during installation) virt-install --name=guest02-c6 --disk path=/var/lib/libvirt/images/guest02-c6.img,size=10,sparse=false --graphics=spice,keymap=fr --vcpus=2 --ram=2048 --location=http://spacewalk.example.com/pub/dist/centos/6/x86_64/ --extra-args="ks=http://spacewalk.example.com/pub/ks/el6/guest02.el6.cfg ip=192.168.2.12 netmask=255.255.255.224 gateway=192.168.2.10 dns=192.168.2.10" --os-type=linux --os-variant=rhel6 --network=bridge:vlanbr6,model=virtio Someone have setup similar environment ? Regards. Baptiste.

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Re: [CentOS-virt] Resize guest filesystem question
by Jeff Boyce 27 Feb '12

27 Feb '12

Responding to the daily digest, see comment at bottom. > Message: 1 > Date: Mon, 27 Feb 2012 14:01:27 +0100 > From: Markus Falb <markus.falb(a)fasel.at> > Subject: Re: [CentOS-virt] Resize guest filesystem question > To: centos-virt(a)centos.org > Message-ID: <jifur8$pmi$1(a)dough.gmane.org> > Content-Type: text/plain; charset="iso-8859-1" > > On 24.2.2012 21:28, Sergiy Yegorov wrote: >> Fri, 24-Feb-2012 12:05:55 Jeff Boyce wrote: >> >>> 6. Then I ran resize2fs /dev/vda2 and got the result that the >>> filesystem >>> is already xx blocks long. Nothing to do! >> Before you can resize filesystem, you have to resize partition. >> If it is only 2 partitions on /dev/vda, you can use one of two ways: >> 1. Resize partition from host system (I think it is not the best idea for >> root >> partition operations): >> Run fdisk /dev/vg/lv_guest1root, delete second partition and create new >> one >> which starts from the same place but takes all available space, after it >> you >> can boot guest (in single mode) and run resize2fs. >> 2. Boot VM from any 3-party (LiveCD or any) with access to virtual disk, >> and >> do the same: in fdisk delete existing partition, create new one and run >> resize2fs on it. Or just use parted to do it in one command. > > 3. You can repartition from the guest itself > Do as in 2. After saving the new partition table fdisk will probably > request a reboot for using the new table. reboot, then resize the fs. > > -- > Kind Regards, Markus Falb > Thanks to everyone that replied. Ed gave me the right clue that I was missing (and is apparently missing in a lot of the how-to's that I reviewed which only said to expand the LV, then expand the filesystem). I had to expand the partition before expanding the filesystem. So for my solution I rebooted that particular VM using SystemRescue LiveCD, then started GParted and expanded the partition which also expanded the filesystem in a single step. Then rebooted using the VM's image and #df -h now shows the expanded LV and a file system on the full space. Jeff

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