Overview

The hardware required doesn't have to be particularly exotic. Perhaps a CPU that supports VT-x (the virtualisation extensions) is the only requirement. You can run without those but you're back in the somewhat slower world of full software emulation.

Somewhat more pressing is RAM. Lot's of RAM. In fact, all the RAM!

Storage is less pressing as OpenStack is pretty good about reusing disk images and only keeping instance deltas. Without a tweak or two, though, it does work on the basis that you must have backing store for all of the VMs you create. That's more of an issue if you happen to be using exotic fast but essentially "small" (if multi-hundred GB disks are considered small) M.2 NMVe disks.

Update: if you do OS updates regularly then your delta from that base image increases, however those update deltas are not shared so if you've a dozen VMs all running nightly updates then you'll have a dozen times the delta chewing up disk space. There's no easy fix, of course, you'd have to create a new base image using the latest OS parts and rebuild your VM from the new image.

Example

This is an example box created for this project. It is deliberately focused on small size and low power. The small size (mini-ITX motherboards) limits the amount of RAM to two DIMMs -- fortunately, there isn't so much of a price premium for the largest DIMMs these days. Costs are ex-VAT in January 2016:

• motherboard - GigaByte GA-H170N-WIFI

  This is a mini-ITX motherboard (17x17cm) packed with features for £84:

  • Intel Skylake (6th gen) CPUs, socket 1151

  • DDR4 RAM (2x DIMMs, up to 32GB)

  • PCIe x4 M.2 connector (NVMe, SATA)

  • 2x SATA Express

  • 2x GbE LAN

  • USB 3.0 (incl. type C)

  • 802.11ac WiFi

  • 1x DVI-D, 2x HDMI 1.4 (4k)

  • HD Audio

  • UEFI support

  • Intel RST support

    This is relevant as although such fakeraid is frowned upon, Linux has very good dmraid support for it.

    That said, this particular board has issues as the vendor doesn't seem to think that there are operating systems other than Windows and that only certain Windows versions can support RST and ... and ...

  • VT-d support

    Perhaps not immediately useful for the SOHO lab but if you spent another £80 on a dual Intel I350 Ethernet card then you can start using SR-IOV.

• CPU - Intel i7-6700T or i3-6100T

  • i7 is 4c/8t (£230 - but rare as hen's teeth!)
  • i3 is 2c/4t (£77 - very good value for money)
  • both are 35W TDP
  • both support VT-x
  • low profile cooler, eg. Silverstone NT07-115X (£13)

• RAM - Crucial 16GB DDR4 DIMMs (£69)

• Storage

  • Samsung SM951 M.2 PCIe NVMe (256GB/128GB) - up to 32 Gb/s (£96/£56)

    On this motherboard the M.2 slot is underneath.

  • 1TB WD WD10JFCX WD Red (£49)

    Depending on your choice of box and cooling fan you may want to be careful about the thickness of the disks you choose. For the M350 box the disks hang from panels over the top of the motherboard, in particular, one over the top of the CPU & cooling fan arrangement the other over the top of any (low profile) PCI card you may want to add.

• Chassis - Mini-box M350 (£97 incl. PSU)

  titchy! Think of a large textbook.

• PSU - picoPSU 80W

  cf. a laptop power supply