I have a small AM1 server I built awhile back. It currently is running Ubuntu 14.04.2 headless in the closet. The install is nothing more than a kvm host, and I have been virtualizing everything I do. This was done for learning as well as I found it easier to have single systems (vms) that do one job as opposed to one system doing multiple jobs.

I am beginning to rethink this though. I can't help but think I am making more work for myself to keep multiple vms updated, performance penalties for vms as opposed to bare metal ( minecraft server comes to mind).

I guess my question is at what point does virtualization make more sense than single machine for a home server.

My uses - file server, torrent seedbox, apt-cache-ng proxy, minecraft survival ( 4 players max ).

The server is not high powered is another reason I am looking for advice. AM1 Kabini 5350, 8gb memory, 120gb ssd, 1tb hdd.

What is my best option?

Isolation can be acheived.

Multiple different OS can be installed.

Used as a test install system.

Using KVM there is hardly any penalty except for graphics and such...

virtualization is not a necessity ... but it is a nice tool for security, customization, and testing. i'd keep on using it. write scripts to boost your efforts and automate what you can.

+1

Learning how to use a virtualisation platform of some sort is now a pretty essential skill. If you're a home user then you may as well get the experience.

If you're a "working" systems admin that these days it's critical to have some for of experience in virtualisation in one or more of KVM/Xen/VM.

Everything is moving towards the cloud and virtualised environments so it is a good idea to learn how it all works.

If you want a more lightweight solution that is easier to maintain you might want to look into containers instead of VM, like Docker or LXC.

For a low maint setup, in the past you may have thought of OpenVZ - now, I'd have to second LXC.

I still think cgroup/containers is a half-arsed attempt to fix (competing) workload scheduling on Linux, but it's the best we have.

I'm a slacker.
The less work I have, the better.
With virtualization you have less work maintaining your services, as if you ever need to switch servers all you have to do is migrate the VMs to it.
Also, you can backup the whole system (the VM image file and config), not just the data in it. Incrementally.
Deploying new VMs is also mostly automated: I have a read-only "gold-image" with a base generic system, then I attached another read-only image to it with the new operating system's config, finally a read-write image is attached so changes can be saved to it.
If that system becomes borked/compromised/infected it is a simple matter of scraping the read-write image and revert to a pristine system.

Performance penalties are minimal (I use qemu/kvm/libvirt).

Ive been doing some reading on LXC and it looks interesting although much of what I read was over my head. Couple questions.

Do containers have full access to the hardware or is there a layer of overhead between the container and the host?

Is the container entirely self contained, a separate os install or is it using the host os as its core? Basically can I run updates on the host and be done or do I need to do it for each container?

Depends on how you configure the container. If you bind-mount the /dev directory to the container (or only those parts of that directory that you want the container have access to) then it has hardware access. It is for example possible to run applications like Steam inside a container, which need access to the graphics hardware. You may of course have the need to align driver versions between the host and the guest OS for this to work.
This also depends on your setup. It is possible to use the host OS as the basic system and only have the changes made by installing and running an application inside the container. It is also possible to run entire distributions in a container. The most common usage, I would think, is to create on base filesystem, independent from the host OS, and use that as a base for your containers, so that you only have to update the base filesystem to get the updates for all containers, except for those applications installed inside a container. This makes it possible to run different versions of the same software on top of the same OS at the same time.

+1

many cloud providers make cheap or free or pay as you go services available for learning. I used the free tier of AWS a few years ago and learned a lot. i had done much virtualization even before that which helped a bit. virtualization is in heavy use in the embedded development arena, too, mostly QEMU for emulation for testing and image building. BTDT