[Discuss] Virt-Manager

[markw at mohawksoft.com]

Ubuntu is based on Debian. It may be version differences, who knows?
Anyway, QEMU can emulate different processors, for instance, it can
emulate the ARM processor for Android development, and, as you've
experienced already, it is quite slow.

The real benefit is using the x86_64 processor's ability to paravirtualize
an environment by allowing native code to run in a protected virtual
memory space where any instruction that exceeds its "protection" creates a
trap to the hypervisor where the hypervisor can then emulate the
instruction.

Most code in this environment runs at native speed. Using the VirtIO stuff
increases performance even better because the hypervisor isn't emulating
physical hardware. There is a driver in your VM that calls into the
hypervisor to do the I/O operation in the hypervisor.

You can even use the emulator to do kernel development. You can use gdb
with the emulator to step through kernel code.

These days, I don't like to pollute my "work station" with all the various
build tools. Its always a PITA to get multiple different environments to
work along side each other. This is no longer an issue. Build for CentOS?
Set up a centos VM. Build for Debian? Set up a Debian VM. Build for
Windows? Set up a Windows VM. Different versions of an OS? Set up multiple
VMs with different version. Need to test upgrade? Create VM of old version
and practice upgrading it.

Lately, I've been using ZFS for VM management. I have a ZRAID system and I
create "zvols" (ZFS equivalent to LVM logical volumes) for each VM. Create
them "sparse" and enable compression. I have even used the "snapshot"
capability to test on VMs, take a snapshot, start up vm, test code that
nukes VM, shut down VM, revert snapshot, start again.

KVM/QEMU has completely changed how I do software development. I almost
*never* run make in my "work station" environment. I am always compiling
in a specific VM.

Anyway, have fun. Virtualization is a little heavier than containers, but
well worth getting to know better.


> There isn't a package named /qemu-kvm/ in Debian. It was missing their
> /qemu-system-x86/ package.
>
> It's now running in real-time, I'm seeing no delay. The image took only
> 15 minutes to install this time. Better than an hour and a half.  :-)
>
>
> On 10/20/21 19:24, markw at mohawksoft.com wrote:
>> Try this:
>> sudo apt-get install qemu-kvm
>>
>>
>>> Thanks. In Debian. that would be qemu-system-x86, so I installed that
>>> with (again) virt-manager and the image is now running at almost
>>> real-time. Not sure what else q-s-x86 added, but it looks like it might
>>> work now.
>>>
>>> Upon launching virt-manager to create the vm after the q-s-x86 package,
>>> the message re KVM not installed did not appear.
>>>
>>>
>>> On 10/20/21 5:35 PM, markw at mohawksoft.com wrote:
>>>> Try installing qemu packages
>
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