Why KVM??? Help please!

KVM will be working just like or better than VMware. KVM is available as free or paid depending on your choice and you can convert any installed Linux into a KVM Hypervisor with few commands. All the features which are there in VMware by buying additional components like DRS, vMotion, etc., come in KVM by default.

KVM will work just like VMware and is being used heavily by big companies like Amazon(AWS) and other players.

If you are using any of the open-source cloud technologies then KVM tends to have better interfacing with other open-source cloud solutions than vSphere. The other reason you would want to use KVM is cost.

Perhaps if you had a specific scenario then it would be easier to make a call on which is the better solution between KVM and vSphere, or perhaps even another virtualization technology.

KVM is becoming the standard in open source, with major companies moving over from other open source technologies. That will result in better support, more features and perhaps even defacto standard status, entrenching it even more into the industry.

vSphere, though legacy, is owned by a leader in the industry with heavy investment in support, features, and most importantly, those peaceful nights asleep knowing someone will take responsibility if something breaks down.

At the end of the day, you are dealing with industry leaders whichever choice you end up with.

Small support team, small cluster, low core count, use VMware products
Large support team, large clusters with many cores, use KVM.
KVM scales better, orchestration better, performs better and supports a wider range of hardware.

Far from being an expert, my opinion is that the positive sides of KVM are:

Lower costs and open-source which gives the abilities to customize it according to the specific needs of each customer.

We use VMware and KVM. We find that KVM is a lot simpler to use and it provides the virtualization we need for Linux and Windows. For us, VMware does not offer any advantage. Moreover, KVM is free.

Stay with vSphere or Acropolis (Hyperconverged). 
I will not look at KVM or HyperV unless it is an absolute decision made by C-level.      

KVM is just another virtualization manager. But unlike VMware, orchestrating deployment does not require a whole gamete of tools and support systems.

KVM can be orchestrated with ssh + a simple script, and there are plenty of opensource management tools if you need GUIs.

There are many KVM implementations like oVirt(open source), RHV from RedHat commercial open source, Proxmox, etc., and I suggest you use either oVirt or Proxmox as they are easy and completely open-source.

In addition to free, KVM has other assets like:
- Easy migration of VM from VMware to KVM
- Very low usage of cpu+memory of the hard server (hypervisor)
- Stability and scalability

About good use cases, I can mention Saham Assurance Cameroon with whom I work with and one other partner for whom we deployed KVM to dematerialize its servers.

Both are using KVM in production since 2017 without the need for any support or help from anyone.

In the case of SAHAM, we migrate VMs from VMware to KVM. We created corresponding VMware VM's server in KVM with the same technical specifications. We migrate the virtual disk from VMware to KVM disk format and we integrate them very smoothly and the servers worked at the first try.

In the case of the other one, we created VM with the same specifications and the same name of the corresponding hard server and then we save them and restore data in the VM servers with success!

The main goal might be that it is free. But do not think that just being free is not good, because it is very good.
We have several examples in large companies such as IBM.

Hi Jacek! I am a multi platform user in virtual world and I can say that KVM is more and more used. It is powerful and flexible. Almost all datacentres are using it.
When I mean flexible, I mean in compatibility to come from or go to all other platforms, and that's not all, it is free and have support on a lots of community's. You also have payed support on a totally free environment like "Proxmox" a ready to run KVM with a nice web gui.
I other words, KVM disserve the time to be learned, it is environment friendly like all open sources.
It is hard to do a fast switch from VMware, I do know it, but like I said it's worthy.