QEMU/KVM Setup

TheProf

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I've been playing around with different virtualization apps like virtualbox, specifically looking to run something on by desktop to test out different distro's and use it as a lab for testing various configs before applying these changes to my personal computer.

I've used VMware workstation quite a bit on Windows, never really liked Hyper-V. When I switched to Linux, I gravitated towards virtualbox because it was quite simple to use and it works quite well, no major issues.

I then discovered kvm/qemu/libvirt along with virt manager and cockpit, makes for a solid option, especially from a performance perspective, definitely an improvement over virtual box.

What do folks on here use for virtual machines software?
 


What do folks on here use for virtual machines software?
I use QEMU(command line)for Linux VMs, and VirtualBox for a Windows VM. If you plan on using QEMU, I recommend you to read this https://doc.opensuse.org/documentation/leap/archive/15.1/virtualization/html/book.virt/index.html I learned a lot from reading that. :) By the way, KVM is a kernel module, so you don't need to install it, just install QEMU, and if you want/prefer a GUI, install virt-manager, which is a front end for QEMU.
 
I use QEMU(command line)for Linux VMs, and VirtualBox for a Windows VM. If you plan on using QEMU, I recommend you to read this https://doc.opensuse.org/documentation/leap/archive/15.1/virtualization/html/book.virt/index.html I learned a lot from reading that. :) By the way, KVM is a kernel module, so you don't need to install it, just install QEMU, and if you want/prefer a GUI, install virt-manager, which is a front end for QEMU.

Good to know! I could have sworn I thought KVM was part of the QEMU install, but actually it was never installed... I just tried running kvm --version but it could not be found. Good to know about KVM / QEMU and thank you for sharing the link, I definitely need to do some reading up on KVM :)
 
If you use it on your desktop virt-manager will do just fine, that's what I do, it even works fine when using it through X11 forwarding on a remote system although there can be a bit delay in that case.
 
If you use it on your desktop virt-manager will do just fine, that's what I do, it even works fine when using it through X11 forwarding on a remote system although there can be a bit delay in that case.

just virt manager? No need for QEMU?
 
virt-manager is the graphical front-end for QEMU.
 
Ok, so basically:

KVM type 1 hypervisor)

QEMU is the type 2 hypervisor used as an emulation layer. You then use Virt Manager to connect to the emulation layer, in this case QEMU.

I assume you can also use Virt Manager to connect to KVM?
 
Let me show you a screenshot, maybe that will make things clearer for you? If I remember correctly KVM is the kernel part and QEMU is the visualizer/emulator.
 

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To clarify this a bit.

Let's say I am using ESXi, this hypervisor is type 1, meaning the hypervisor runs directly on the host hardware, no need to load the OS like type 2 (virtualbox). Type 2 on the other hand, relies on the OS layer, so typically you'd have better performance with type 1 hypervisor.

What I am trying to understanding with QEMU / KVM, is if these two services are similar to the way type 1 vs type 2 hypervisors.

When I do some reading online on KVM, I get that it is a kernel module and I see that you dont need KVM to run QEMU. I also see KVM referencesd as Type 1 hypervisor, whereas QEMU is being referenced more as a type 2 hypervisor.

This is what I meant earlier when I was referring to type 1 vs type 2.
 
QEMU/KVM are type 1. This might help to clarify things a bit https://phoenixnap.com/kb/what-is-hypervisor-type-1-2

I was doing some more reading and thank you for sharing the link above btw. Based on what I understood, that QEMU in itself is a type 2 hypervisor, however if QEMU is used with KVM, it then becomes Type 1.

 
I worked for a financial trading platform start-up around 2008. Their budget was almost non-existent and I built their entire virtualization environment out of KVM and libvirt on top of CentOS. The only thing that cost money was the hardware itself. It ran on that setup for 6 years before the company was sold to a larger financial firm.

KVM is a very solid platform to build virtualization out of. I use it on my home server to host VMs, Plex, etc.
 
You can also have a look at Proxmox which has KVM integrated into it, I have never used it but from my understanding it's basically KVM with a detailed web-interface and can do anything that KVM can do.
I currently use KVM as my home lab setup on my desktop and on my home server I use containers to run services such as Plex, Emby and other applications.
 
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You can also have a look at Proxmox which has KVM integrated into it, I have never used it but from my understanding it's basically KVM with a detailed graphical interface and can do anything that KVM can do.

I currently use KVM as my home lab setup and on my home server I use containers to run services such as Plex, Emby and other applications.
I've used Proxmox also. It's nice but had a few bugs in it. If you want a web-based GUI, it's nice. Back when I used it between 2014-2018. You had to have the pay version to get the clustering features Not sure if that I still true as we've since migrated into a large vSAN clusters.
 
You can also have a look at Proxmox which has KVM integrated into it, I have never used it but from my understanding it's basically KVM with a detailed graphical interface and can do anything that KVM can do.

I use Proxmox with my dedicated server hosts (3 hosts in a cluster), great free option for open source hypervisor. I was using ESXi/vCenter before using the VMUG Advantage subscription to get the 1 year license. But unless you're running enterprise server gear, I found it to be unstable in my lab, I just use lenovo desktop PCs to keep things quiet and consume as little energy as possible. The lab is not always turned on and so I like to use virtualization on my main desktop to do quick testing and for anything that I dont need to run for long periods of time.
 


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