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Lab 28.3. Installing a VM from the Command Line


I am currently using Centos Stream and have found that the command
sudo qemu-system-x86_64 -hda /var/lib/libvirtd/myimg.qcow2 \ -cdrom /teaching/LFCW/RESOURCES/LFS201/CorePlus-current.iso -usbdevice table
produces the error:
bash: qemu-system-x86_64: command not found...

Looking around the bazaars, it seems that qemu-system-x86_64 is no longer supported from Centos 8 onward. is there any instructions for a way forward (emu-kvm) or an exercise to replace this one?


  • coop
    coop Posts: 915

    Absolutely true unfortunately. Red Hat no longer ships these stand alone binaries for different architectures and expect you to run under kvm as in the previous exercise. I don't know if you can find such an rpm on any unsupported repository. However, as we explain in one of our developer courses you could download, configure, compile and install from source by doing:

    git clone https://git.qemu.org/git/qemu.git
    cd qemu
    git submodule init
    git submodule update --recursive
     ./configure --target-list=x86_64-softmmu
    Put in the number of cores or cpus for $(nproc)
    make -j $(nproc)  
    Install QEMU into /usr/local/bin/ as root.
    sudo make install

    However, this will consume a long time, require about 3 GB during the build phase, and is likely to fail at various points due to lacking of various software packages and development libraries, such a libpulse-devel and ninja* etc. You really have to be dedicated go go through this :wink:

    I'd recommend living with the libvirt/kvm stuff on RHEL/CentOS 8 as it works well.

  • richiemcg

    Thanks @coop much appreciated. Looks like a real pain and gives me flashbacks of some legacy systems I used to maintain....

    BTW In the LFCS exams Domains and competencies under Service Configuration we are expected to show that we can manage and configure Virtual Machines.
    Since the exam is in the command line would it be advisable to learn to use libvirt, to manage a vm as virt-manager will not be available in the exam?
    My thinking is in terms that CentOS 7 will not be available soon, as the exam will be moving to CentOS Stream this coming quarter.

  • coop
    coop Posts: 915

    I really don't know what they do on the exam. I was never happy having that listed on the "Domains and Competencies" for the kinds of reasons you are talking about. It takes quite a bit of time and energy to do this sort of thing, and the different distros have always had divergence on the tools and how they are implemented. The sections on VMS and Containers in LFS201 are there because we think admins must start to get familiar with them, but there really is no way they could be done in depth. I don't like to give exam advice but I would encourage you not to worry much about this one, I don't know how I could design a performance-based limited time exam probe on this :wink:

  • richiemcg

    Thanks @coop that's put things in a better perspective for me and settled me down abit for the exam.


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