Results 1 to 9 of 9

Thread: Qemu/kvm as a tool for handling 7.4.2 install from ISO

  1. #1
    Senior Member registered user
    Join Date
    Sep 2006
    Posts
    801

    Qemu/kvm as a tool for handling 7.4.2 install from ISO

    To me, it seems that rather few people use Qemu/kvm as a tool for handling Knoppix. Both for testing and running images, to avoid the CD/DVD burning step, and a lot of other things. Here, I will just tell how I used it to create a plain flash install og 7.4.2 very easily. Basically the same story I have told before, but now it is 7.4.2. I did this on a Knoppix 7.0.5 install.

    Download and check the ISO image, insert the USB stick to install on in a USB (preferably USB3.0) port.
    Then check qemu/kvm-modules are in place, and find out what the drive is called

    Code:
     $sudo modprobe kvm && modprobe kvm-intel
     $fdisk -l
    Log into the download directory and run the DVD image in qemu with kvm acceleration. Here, the stick has been mapped as /dev/sdc, I run with 1GB memory, and boot the image

    Code:
     $sudo qemu -machine accel=kvm -cdrom KNOPPIX_V7.4.2DVD-2014-09-28-EN.iso -hdb /dev/sdc -m 1024 -boot d
    A small window with the Knoppix boot prompt opens - here you can enter kernel and keyboard options etc. Then a somewhat larger window where Knoppix runs, apperars. You can use this to check different aspects of the new version.
    Then click the Install Knoppix to flash icon. Beware of the pecularity occurring next: You must choose install to hard disk, because when starting the virtual machine with the -hdb /dev/sdc parameter, the USB stick has been mapped to /dev/sda. You will be able to check it from the size of the drive.

    You have the ordinary choices - I recommend to start with the simplest procedure: Let Knoppix format the whole drive as FAT32, use a 4GB overlay file (not partition) if the stick allows it.
    For me, this worked very well on the first try. I immediately used the stick to boot another PC where the whole disk was to wiped out and setup anew for a new install.

  2. #2
    Senior Member registered user
    Join Date
    May 2006
    Location
    Columbia, Maryland USA
    Posts
    1,631
    Greetings, Capricorny.

    I have 3.5 Gb ram to work-with.
    Is this enough to successfully treat DVD-size isos using this process?
    TIA.

  3. #3
    Moderator Moderator
    Join Date
    Nov 2010
    Location
    Germany/ Dietzenbach
    Posts
    1,124
    Then check qemu/kvm-modules are in place,..
    Also many computers with AMD CPU and not Intel can use qemu/kvm
    Test Image kvm-qemu

  4. #4
    Senior Member registered user
    Join Date
    May 2006
    Location
    Columbia, Maryland USA
    Posts
    1,631

    I have other problems, it turns out.

    Quote Originally Posted by utu View Post
    I have 3.5 Gb ram to work-with.
    Is this enough to successfully treat DVD-size isos using this process?
    TIA.
    I appreciate the posting of this helpful idea, however...

    Many forum users won't be able to use this idea because their cpu(s) aren't capable
    of doing the necessary virtualization. The Intel site below may help some figure this out.

    The process I went through was as follows:
    1. egrep '(vmx|svm)' --color=always /proc/cpuinfo gives a null result; not encouraging.
    2. virtualization (may?) require 64-bit cpu(s) & OS; we have that, anyway.
    3. my bios material gives NO clue whether my cpu(s) are capable of virtualization or not; also not encouraging.
    4. Intel spec sheets let you know whether your cpu(s) are capable of vt-x virtualization; mine aren't. See, for example:
    http://ark.intel.com/products/37253/...=t4300+pentium

    One needs to substitute their own cpu designation, of course.
    My rig is dual T4300s.

  5. #5
    Senior Member registered user
    Join Date
    May 2006
    Location
    Columbia, Maryland USA
    Posts
    1,631
    My apologies, but you will have to add your own http://
    to make the Intel link work.
    And, I can't explain what's happening there.

  6. #6
    Senior Member registered user
    Join Date
    Sep 2006
    Posts
    801

    For this kind of use, you don't really need virtualization

    Quote Originally Posted by utu View Post
    I appreciate the posting of this helpful idea, however...

    Many forum users won't be able to use this idea because their cpu(s) aren't capable
    of doing the necessary virtualization. The Intel site below may help some figure this out.

    The process I went through was as follows:
    1. egrep '(vmx|svm)' --color=always /proc/cpuinfo gives a null result; not encouraging.
    2. virtualization (may?) require 64-bit cpu(s) & OS; we have that, anyway.
    3. my bios material gives NO clue whether my cpu(s) are capable of virtualization or not; also not encouraging.
    4. Intel spec sheets let you know whether your cpu(s) are capable of vt-x virtualization; mine aren't. See, for example:
    http://ark.intel.com/products/37253/...=t4300+pentium

    One needs to substitute their own cpu designation, of course.
    My rig is dual T4300s.
    For the simple kind of use I mentioned, you don't really need virtualization. If kvm doesn't work, it's just to omit the -machine parameter. It will run slowly, but the job will be done - and I'm not sure about the resulting amount of lag in I/O-operations, which is the time-consuming part in this case.
    The modprobe (with AMD CPUs, use kvm-amd instead of kvm-intel) should fail if kvm doesn't work, and the simple command
    Code:
    lsmod | grep kvm
    will tell if kvm is loaded.
    (I also wonder how many use virtualization-resistent CPUs these days.)
    Seems that 3 GB RAM will work - but the -m parameter may have to be be reduced from 1024.

  7. #7
    Senior Member registered user
    Join Date
    May 2006
    Location
    Columbia, Maryland USA
    Posts
    1,631
    Greetings again, Capricorny.

    I admit to being a Luddite, opposed to learning anything new unless
    or until it is absolutely necessary. But,

    My impression is that a qemu approach WITHOUT hardware acceleration
    is a poor alternative to that of making a LiveCD to accomplish the
    same purpose. The same purpose being the eventual production of a
    LiveUSB derived from a downloaded iso. The time and cost of making
    an interim LiveCD product are rather minimal, and for the most part,
    already automated.

    A qemu approach WITH hardware acceleration seems a much more complex
    approach than the "poor-man's install" alternative which I understand
    Klaus K has recently provided 7.4 which also makes an interim LiveCD
    unnecessary. Below is my slight edit of Klaus K's 7.4 release notes**
    almost subliminal advertisement of this new feature:
    The flash-knoppix script since Knoppix 7.4.0 supports on-the-fly conversion
    of a DVD ISO image for direct flashing of a USB pendrive or disk. By using
    this, the intermediate step of burning a DVD and booting from it, can be
    skipped. For burning a
    CD- or DVD-size LiveUSB,
    only one single .iso file matching your
    language and version choice, is sufficient. For using this feature, just add
    the name of the .iso file as commandline parameter to flash-knoppix like this:
    flash-knoppix KNOPPIX_V7.4.1DVD-2014-09-28-EN.iso
    And, of course, update 'V7.4.1, etc' as appropriate.

    **See for example, http://knopper.net/knoppix/knoppix742-en.html

  8. #8
    Senior Member registered user
    Join Date
    Sep 2006
    Posts
    801
    Quote Originally Posted by utu View Post
    Greetings again, Capricorny.

    I admit to being a Luddite, opposed to learning anything new unless
    or until it is absolutely necessary. But,

    My impression is that a qemu approach WITHOUT hardware acceleration
    is a poor alternative to that of making a LiveCD to accomplish the
    same purpose. The same purpose being the eventual production of a
    LiveUSB derived from a downloaded iso. The time and cost of making
    an interim LiveCD product are rather minimal, and for the most part,
    already automated.

    A qemu approach WITH hardware acceleration seems a much more complex
    approach than the "poor-man's install" alternative which I understand
    Klaus K has recently provided 7.4 which also makes an interim LiveCD
    unnecessary. Below is my slight edit of Klaus K's 7.4 release notes**
    almost subliminal advertisement of this new feature:

    CD- or DVD-size LiveUSB,

    And, of course, update 'V7.4.1, etc' as appropriate.

    **See for example, http://knopper.net/knoppix/knoppix742-en.html
    Well, I think your impression in this case is simply wrong. With or without acceleration does not make much of a difference in the simplest use case, where the task is merely to run flash-knoppix.
    It is when you use qemu to check out the new version, that the difference really kicks in. And being able to avoid booting from optical media is time and effort saving. Most smaller laptops sold today don't even have an optical drive.

    But qemu surely can't beat that new command line creation option in flash-knoppix! Starting with 7.4.X only three days ago, I wasn't aware of it .
    I will probably use it in the future, at least sporadically. The great advantage of using qemu/kvm is that you can check out how the new release works before creating a flash install.

    Qemu/kvm is also an extremely good general tool, almost ideal for running Knoppix in a VM with no adaptation at all: Put a Knoppix instance on a separate partition, have a non-mounted boot partition, just use old grub with qemu to boot the main harddisk MBR, select the actual Knoppix partition and run it.

  9. #9
    Senior Member registered user
    Join Date
    May 2006
    Location
    Columbia, Maryland USA
    Posts
    1,631
    .
    Hello again, Capricorny.

    You have energized me to try out your original suggestion, despite my
    admitted inertia. I have a Win8 portable as well as my trusty Win7.
    Both are low-end Inspirons. I've not been using the Win8 up to now
    for Linux purposes. Turns out the Win8 portable, which has dual
    Celerons, HAS built-in virtualization capability and moreover passes
    the kvm test using a 7.4.1 LiveUSB.

    The hardest part was getting around Win8's Secure Boot and Windows-to-go
    obstacles. That done, the kvm test was very encouraging. Knoppix 7.4.1
    looks good on the newer machine.

    I shall now start trying to decipher the meanings of all the qemu
    parameters. Once over that hurdle, I expect I may agree to all, or at
    least most, of your counter-arguments. I expect some differences may
    exist between your device assignments and my own; and, I'd not like
    to write over Win8 in this process.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •