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oVirt 3.4 Means Management, VMs Can Live On the Same Machine

Posted by timothy on from the right-there-in-the-open dept.

darthcamaro (735685) writes "Red Hat's open source oVirt project hit a major milestone this week with the release of version 3.4. It's got improved storage handling so users can mix and match different resource types, though the big new feature is one that seems painfully obvious. For the first time oVirt users can have the oVirt Manager and oVirt VMs on the same physical machine. 'So, typically, customers deployed the oVirt engine on a physical machine or on a virtual machine that wasn't managed or monitored,' Scott Herold, principal product manager for Red Hat Enterprise Virtualization said. 'The oVirt 3.4 release adds the ability for oVirt to self-host its engine, including monitoring and recovery of the virtual machine.'" (Wikipedia describes oVirt as "a free platform virtualization management web application community project.")

11 of 51 comments (clear)

  1. Still trying to wrap my head... by TWX · · Score: 2, Interesting

    ...around the supposed benefits of server-side virtual machines.

    You're running an operating system, so that you can run a software package, so that you can run another operating system, so that you can run another software package that is then interfaced-to by users or other stations on the network?

    I guess that I can see it for boxes that serve multiple, different paying subscribers that each get their own "box", but wouldn't it just make more sense to size the applications to use the host OS on a single box as opposed to running multiple copies of operating systems and services that eat resources when the virtual hosts all belong to a single customer?

    --
    Do not look into laser with remaining eye.
    1. Re:Still trying to wrap my head... by invictusvoyd · · Score: 3, Funny

      but wouldn't it just make more sense to size the applications to use the host OS on a single box as opposed to running multiple copies of operating systems and services that eat resources when the virtual hosts all belong to a single customer?

      Some hosting customers require control of the OS to run their proprietary security and optimization apps . Besides, virtualization allows for efficient utilization of hardware , power and rackspace.

    2. Re:Still trying to wrap my head... by MightyMartian · · Score: 4, Interesting

      As someone who uses KVM VMs, I see a number of advantages:

      1. More efficient use of resources. A dedicated server usually idles a lot, and those cycles do nothing. Running guests allows empty cycles to be put to work.
      2. Load balancing and moving resources around is a lot easier. Have a busy host, move a guest to an idle one.
      3. Hardware abstraction. This is the big one for me. Guests are no longer tied to specific hardware, and I can build a new VM host and move guests to it a helluva lot more painlessly than I could with an OS installed directly on hardware.
      4. Backup options. Coupled with functionality like logical volumes, I can make snapshots for backup or testing purposes with incredible ease.

      --
      The world's burning. Moped Jesus spotted on I50. Details at 11.
    3. Re:Still trying to wrap my head... by omglolbah · · Score: 2

      Well, one reason is when you have a vendor which does not support your system -at all- if you install any unauthorized software packages or even OS updates that have not been cleared.

      At that point you want 'clean' VMs that follow the vendor spec exactly.

    4. Re:Still trying to wrap my head... by kthreadd · · Score: 2

      GNU/Linux with LXC and Btrfs will give you more or less the same isolation that you get with virtual machines, but with no overhead. The moving to new hardware is still somewhat lagging behind, but once Criu becomes useful I see no reason why that shouldn't be possible.

    5. Re:Still trying to wrap my head... by DarwinSurvivor · · Score: 2

      FreeBSD also does something similar with its jail system. It's not quite a full VM, but you can still assign dedicated IP addresses and have a separate filesystem (or null-mount the existing one inside of it).

    6. Re:Still trying to wrap my head... by jimicus · · Score: 2

      A couple off the top of my head:

        - You wouldn't believe the number of poorly written applications that will happily bring a server to its knees no matter how powerful. This way you can reset just that application, not the whole business.
        - An application that was never written with any sort of HA in mind can be made highly available without any changes.

    7. Re:Still trying to wrap my head... by Lennie · · Score: 3, Informative

      And Solaris (and open source forks) with Zones has had this for many, many years too.

      --
      New things are always on the horizon
    8. Re:Still trying to wrap my head... by Lehk228 · · Score: 2

      then you find a vendor who has not been asleep at the switch for the last decade and a half

      --
      Snowden and Manning are heroes.
    9. Re:Still trying to wrap my head... by nine-times · · Score: 4, Informative

      I may be confused, but... are you questioning the whole idea of hypervisors on servers at all?

      There are a lot of reasons for that. One of the simple reasons is that it's cheaper. When you're working in IT, you often have a bare minimum of hardware you have to buy with each server in order to be safe, e.g. dual hot-plug power supplies, hot-plug RAID enclosures and drives, lights-out management, etc. Because of that, each server you buy is going to end up being about $4k minimum, and the price goes up from there. If you have to buy 5 servers, you might be spending $25k even if they aren't powerful servers. However, you may be able to run all of those servers on a single server that costs $10k. In addition to the initial purchase being less, it will also use less power, take up less space, and put out less heat. All of that means it'll be cheaper of the long term. It will also require less administration. For example, if an important firmware update comes out that requires a certain amount of work to schedule and perform, you're doing that update on 1/5 of the servers you would be doing it on. Oh, and warranty renewals and other support will probably be cheaper.

      So more directly addressing the question, which I think was, "Why not just buy one big server and install everything on it?" There are lots of reasons. I think the most important reason is to isolate the servers. I'm a big believer in the idea of "1 server does 1 thing", except when there are certain tasks that group well together. For example, I might have one server run the web and database services for multiple web apps, and another run DNS/DHCP/AD, but I don't really want one server to do both of those things.

      And there are a few reasons for that. Security is a big one. There are services that need to be exposed the the internet, and then there are services where I don't want the server running them to be internet-accessible. Putting all of those services on the same physical server creates a security problem, unless I virtualize and split the roles into different virtual machines. Or it may be that I need to provide administrative access to the server to different groups of people, but each can't have administrative access to each other's data. Hosting providers are a good example of this: You and I could both be hosting our web application on the same physical machine at the same hosting provider, and we both might need administrative access to the server. However, I don't want you having access to my files and you don't want me having access to yours.

      Another big reason you'll want to isolate your servers is to meet software requirements. I might have one application that runs on Windows, but is only supported up to 2008R2. I might have another application or role that needs to run on Linux. I might have a third role where I really want to use Windows 2012R2 to take advantage of a feature that's unavailable in earlier versions of Windows. How would I put those things on the same server without using virtual machines?

      Isolating your servers is also good because it tends to improve stability. Many applications are poorly written can cause crashes or security problems, and keeping them on their own VM server prevent those applications from interfering with other applications running on the same physical hardware. I can even decide how to allocate the RAM and CPU across the virtual machines, preventing any one application from slowing down the rest by being a resource hog.

      Aside from all that, there are a bunch of other peripheral benefits. For example, with virtual machines, you have more options for snapshotting, backing and replication, restoring to dissimilar hardware, etc. With traditional installs, I need special software to do bare-metal restores in case something goes wrong, and the techniques used in that software often doesn't work quite right. If virtualized machines, I just need the VM's files copied to a compatible hypervisor, and I can start it up wherever I need to. With the right software, I can even move the whole VM live, without shutting it down, to another physical server.

      There are probably a few other benefits that I'm just not thinking of off the top of my head.

  2. Re:oReally by TWX · · Score: 2

    I can assure you, this software is too new for this feature to be documented in any of their tech books...

    --
    Do not look into laser with remaining eye.