My Virtual Baby Gets A Sibling

You may have seen my earlier post about how I'm finally getting around to doing something with my HP Microserver.

Typical!! No sooner do I start working on it than another great deal comes out for the newer Gen 8 model. Priced at £179 with an £80 cashback promo it was to good a deal to miss. So for the princely sum of £99 the virtual baby now looks like this.

I've transplanted the disks and memory from the old model into this one and will be configuring it up as previously described.

So why did I go for this newer model?

• Faster Intel processor rather than AMD
• Built in HP ILO for remote management.
• Faster SATA controller (6Gb rather than 3Gb albeit only on first 2 disks)
• It looks sexier, gotta love that blue led strip at the bottom
• Because I can!!

There are some upgraded features; USB 3 sockets, 2 NICs, easier access to internals but they're less important to me at the moment.

So did I really need to do this? For what I'm going to be using it for, of course not! But for the price how could I say no.

Using the virtual serial port with KVM

So you've installed some linux virtual guests on your shiney new KVM hypervisor, virt-manager is great for managing them but needs X11. Given the guests are linux wouldn't it be nice to be able to get to the console using CLI? Here's how...

For RHEL 6 guests:

Add the following lines to /etc/grub.conf below the splashimage line

serial --unit=0
terminal --timeout=5 serial console

Then append console=ttyS0 to your kernel line

 kernel /vmlinuz-2.6.32-431.el6.x86_64 ro root=/dev/mapper/vg_rhel6-lv_root rd_NO_LUKS  KEYBOARDTYPE=pc KEYTABLE=uk LANG=en_US.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 rd_LVM_LV=vg_rhel6/lv_swap crashkernel=auto rd_LVM_LV=vg_rhel6/lv_root rd_NO_DM rhgb quiet console=ttyS0

For RHEL 7 guests:

Add the following lines to /etc/default/grub

GRUB_TERMINAL="serial"GRUB_SERIAL_COMMAND="serial"

Amend the GRUB_CMDLINE_LINUX to include console=ttyS0

GRUB_CMDLINE_LINUX="rd.lvm.lv=centos_tos7/swap rd.lvm.lv=centos_tos7/root rhgb quiet console=ttyS0"

Now regenerate the grub configuration

grub2-mkconfig -o /boot/grub2/grub.cfg

Reboot the guest and you're done.

Access your lovely new text console using virsh console <guest name>

My New Virtual Baby

I bought one of these little HP MicroServers last year on a cashback promo deal. I've spent a few months fiddling around with it and researching how best to set it up. So here's my thoughts and details of my final configuration.

The server (model N54L)  cost £119 after cashback and came with 4GB memory and no disks.
I bought an extra 4GB on EBay (£44) and a couple of  Western Digital 2TB green hard drives (£57 each) from Amazon.

What do I want to do with it?

My intention was to configure it as a virtualisation host and have a guest running my Logitech Media Server, allowing me to get rid of an ageing Windows PC currently doing this. Further guests could be spun up for other functions I may want in the future.

Performance isn't a key factor for this given what I'm using it for and as I intend to run the guests on Linux the AMD processor seems fine. I did want resilient storage to guard against drive failure and a low power consumption given the machine will be on for long periods of time. The small physical footprint and low noise level is a bonus too.

What configuration to go with, how about vSphere?

First thoughts were to go with a VMware vSphere solution. A basic free version is available with limits on the physical hardware and missing lots of enterprise features, not a problem for this though. The great thing with this is it can run as a bare metal hypervisor and as the server has a bootable internal USB socket I installed it to a USB stick. This means all your disk space is available for your guests.

The MicroServer is a supported configuration and, having used vSphere and Workstation before, it was easy to set up. This would have been a great solution had it not been for a few gotchas.

• Didn't like having to use the vSphere client to configure it. It's Windows only and also deprecated and doesn't have all the available functionality in it. VMware want you to run vCenter which is WebGui based (yay!) but would consume precious hardware resources as it would run as an additional guest (boo!). Oh yes, and it costs money!!
• The hypervisor doesn't recognise the internal RAID controller (it's one of those nasty fake ones). Although you can join disks together within vSphere to make a large guest storage pool it can't be made resilient.

 

Hmm, okay - how about something Linux-like?

Being a bit of a RHEL fan I thought how about trying their virtualisation product RHEV, or rather the upstream open source version oVirt. This is based around Linux's kvm virtualisation technology.
Ok so this is a bit trickier to set up but I am familiar with it and am even certified in it (click if you don't believe me)
You can't really do this one on a USB stick so added an additional smaller hard drive I had lying around, installed Centos 6 and put oVirt on top of that. This would leave the other drives for guest storage.

So I quite liked this solution. Based around RHEL / kvm which is great (and totally free) and the administration is done through a web gui. Although I didn't try this bit out I would be able to make use of LVM and Linux RAID to create resilient and extendable storage for the guests. These both play very well with kvm and I have experience from work (and did I mention my awesome certifications haha!)

In the end though I abandoned this solution mainly due to the performance overhead of having to run the oVirt management engine and using an extra disk slot to host the hypervisor. Don't get me wrong oVirt gives you a lot but is really more designed for the enterprise environment. It's what the E stands for in RHEV after all.

And so the winner is?

In the end I've gone with a bit of a hybrid solution that takes the best of both worlds. There will be blog posts to follow on how I set this all up but here's the solution in a nutshell.

• Centos 6 minimal installation onto a USB stick, booted from the internal USB port.
• Add virtualisation packages to provide kvm virtualisation
• Use software raid (mdadm) to create a RAID 5 volume. With only 2 disks I hear you say? Yes, I added the 3rd disk later. Thank you Awesome William Matley for the idea.
• Use LVM on the RAID 5 volume to provision logical volumes to host each guest. These can be easily extended, cloned and backed up.
• Administration via ssh and the virsh CLI or virt-manager for the GUI (via X tunnelling). Remote administration via port forwarding on the router.

 So there you have, well done for reading this far. A pretty good virtualisation solution for not a lot of money even if I do say so myself!!