Virtualization

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Hi list, what solution do you use for virtualizzation?

thanks in advance.

20 thoughts on - Virtualization

  • Am 16.06.2015 um 18:50 schrieb Alessandro Baggi:

    Please don’t top-post with fully quoting all previous content. This is a mailinglist.

    Proxmox VE is based on Debian. What does this have to do with CentOS? As it makes use of KVM you can run CentOS on top of it as a virtualization guest.

    Alexander

  • Proxmox is is debian based, but has a really good web based user interface. I use it to host my CentOS VMs and containers. I would be aware that it uses 2.6.32 and I have run into hardware issues. (Mainly issues realtek ethernet adapters, I suggest using Intel adapters)

    Rafeal

  • MMmmm, I really thought ESX was in some way a RHEL derivative but when reading http://www.v-front.de/2013/08/a-myth-busted-and-faq-esxi-is-not-based.html it is clearly not…

    Anyway, I learnt a new thing today ;-)

    oVirt, in my opinion, is a bit harder to implement: basic usage seems to require at least 2 servers, according to http://www.ovirt.org/Quick_Start_Guide#Prerequisites There is an oVirt mailing list where you can ask specific questions:
    http://www.ovirt.org/Mailing_lists

    I would add XenServer to the list, which is currently my favorite, BUT
    it misses a Linux management interface http://xenserver.org/overview-xenserver-open-source-virtualization/source-code.html
    (I let you read what is the upstream ;-) )

  • regardless of all that noise, in RHEL and therefore CentOS, KVM is the preferred and best supported hypervisor.

  • It’s so sad that CentOS is using very old versio on kvm and due that fact live backup without downtime is not possible.

    Anyway, virtsh+virtmanager + kvm is good choice.

  • Am 17.06.2015 um 11:17 schrieb Eero Volotinen :

    just some thoughts

    old != not good new != better

    s/old/stable/
    s/new/not\ mature/

    :-)

  • At Wed, 17 Jun 2015 12:31:49 +0300 CentOS mailing list wrote:

    If host is using LVM for disk partitioning and uses logical volumes for VM
    disks, it is possible to do LVM ‘snapshots’ and these snapshots can then be backed up, all without shutting down the VMs.

  • I dont catch your point. The OP was wide enough in his question in order to allow that discussion.

    Anyway, I’ll add one point: compatibility.

    In our example, we were heavily using VMware ESX and its VM format (at export) is not really supported for import by known solution. We ended at keeping “old” VMWare VMs on ESX and new ones on XenServer.

    Have you got any tool that could satisfy a vmdk to some more friandly format migration?

  • Older ESX had an RHEL 3-based service console; ESXi does not. Logged in to one of my ancient ESX 3.5 hosts:
    [root@esx1 root]# vmware -v VMware ESX Server 3.5.0 build-604481
    [root@esx1 root]# cat /etc/redhat-release Red Hat Enterprise Linux ES release 3 (Taroon)
    [root@esx1 root]#

    The relationship of the service console to the vmkernel is somewhat similar to the relationship of the DomO to the Xen hypervisor, or DOS
    and old NetWare 3; the vmkernel itself, along with all of its loadable modules, is not in any way shape or form ‘based’ on RHEL; RHEL is just used to manage the vmkernel system as a ‘service console.’ This is much like how that Windows 386 (including 3.x, 95/98/ME) was not based on DOS
    (read ‘Unauthorized Windows 95’ by Andrew Schulman to verify) but uses DOS services in a warped fashion (Windows calls a DOS INT which is hooked by an illegal instruction ‘thunk’ back to the 386 mode VMMkernel which is the actual Windows Operating System kernel……).

    With ESXi, VMware wrote their own CLI service console, and did away with RHEL as the service console.

    But to address the direct question of the OP, I use KVM for many things, but I have older hardware in quantity on which I’ll likely run Xen4CentOS with paravirtualized guests, since the processors in these blades do not have hardware virtualization extensions (early Opteron, but still very serviceable for what we want to do). Too many LS20
    blades (about 200) to upgrade them all right now without either donations or other funding (but if anyone wanted to donate some IBM
    BladeServer HS21’s or newer I would not turn down the donation, and we are a 501(c)(3)…… :-) ).

  • Note that making an LVM snapshot, alone, will not provide a consistent image for a backup. If you want to back up a snapshot of a running system, you should use “virsh snapshot-create” to capture the complete state of the system.

    http://searchservervirtualization.techtarget.com/tip/Getting-a-clear-picture-on-KVM-snapshot-basics

    Backups from within the guest will typically be much smaller. I’m working on a flexible snapshot script that supports multiple storage types.

    https://bitbucket.org/gordonmessmer/dragonsdawn-snapshot

  • Perhaps for some of our workloads LXC and LXD (for ‘live migration’
    things) would work, but I have a need on a few VM’s to have different kernels and even completely different yet paravirtualized OSes (pfSense for one, since FreeBSD has paravirtualization drivers) running, even going as far as having mixed 32 and 64 bit installs. Some of the applications we use are a bit version-locked for various reasons beyond our control. And, yes, I’d like hypervisor-based HA and live migration for my pfSense and OpenBSD VM’s.

  • well. current version of kvm on CentOS does not allow live backups without downtime to guest.

    it’s only possible with newer version of kvm and related qemu tools.. so sad..

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