Vmsrv

Philosophy

The Skullspace virtual machine service (vmsrv) is offered to members as a means to share the benefits of best-available hardware.

"Access to computers—and anything which might teach you something about the way the world works—should be unlimited and total."

We focus our virtual machine service on two styles of computing

• Interactive computing -- temporary bursts of high resource use (IO/CPU/memory) by a single user for the purpose of "figuring stuff out", "getting stuff done", "hacking", etc. with the ethic of ensuring resources are freed when not in use. "Always yield to the Hands-On Imperative!"
• General service computing -- always up and running services with reasonable IO, CPU, and memory use that doesn't impair the above.

(services with intense all the time resource requirements should be operated on dedicated servers)

System

• Intel Core 2 Quad Q8200 @ 2.33G] with 4M shared L2 cache (does not have VT extensions!)
• Gigabyte-EP45-UD3L motherboard
• 2x2G (4G) of DDR2 RAM in dual channel configuration, can upgraded to 4x4G (16G)
• 4X1TB SATA hard drives in RAID 10 configuration
• Debian GNU/Linux 6.0 amd64 host operating system
• LVM bock layer, RAID10 is the sole physical volume for the sole volume group (vmsrv). Logical volumes to be created and extended from this volume group as needed
• 1GBit internal NIC on skullspace lan (on host linux bridge skspprivbr), 192.168.1.26
• 100Mbit PCI NIC on VOI public IP switch (on host linux bridge skspvoipubbr)
• Virtualization using Linux Containers (LXC) and VirtualBox 4.0

Thanks to Stef for the donated equipment.

Linux Containers (LXC)

If you want to run a Linux-based x86_64 or x86 based guest, you should consider the benefits of running it as a Linux Container (LXC). These are a newer implementation of OS-level virtualization that is supported upstream.
(FreeBSD fans like Mak and Dave are permitted to gleefully says "we've had that for ages, what took you so long Linux!?")

The main vmsrv kernel (version 2.6.32) directly runs your processes (starting with /sbin/init!) in an independent process space and gives you your own network stack (interfaces, routing tables, iptables) to work with.

Kick-ass performance for your kick-ass userland

Beyond that, leave the kernel to us and focus on rocking your userland! Pretty much any GNU/Linux distro can be booted this way. (some tweaking sometimes needed)

Avoiding the overhead of full-on virtualization and that kernel-hypervisor relationship is an obvious advantage, but even more important is that you won't have to pre-define and hog a fixed amount of memory for your container as you would with a full virtual machine (like VirtualBox, see next section). When your processes are busy they can enjoy bursts of RAM as allocated by the host kernel, when they're idle they can be individually swapped out.

And you get to use all 4 cores. :)

Get your container today

To get your own container, contact Mark Jenkins <mark@parit.ca>. A fresh container with a minimal install can be built and handed over or an existing file system converted.

You can also enjoy the benefits of Linux containers without having to administer your own by signing up for an account on mumd -- a cluster of Linux containers with common LDAP login hosted on vmsrv. (Read more on the mumd page)

Info for vmsrv admins

The linux containers are kept in /var/lib/lxc and started up by /etc/init.d/lxc . /etc/lxc and /etc/default/lxc are also relevant configs)

Virtual Box

Users with accounts on the vmsrv machine are able to run Virtual Box 4.0. There are many supported guest operating systems, and that support is at its best with guests where you can install "virtual box guest additions" which are extra drivers and things that make the guest work better with the host.

Because our CPU doesn't have VT extensions Virtual Box is only able to do a slower "software" virtualization with some insane trickery. A CPU with VT extensions would hardware virtualization possible.

As a result you can only run 32bit x86 guests with a single processor, 64bit and SMP support are not available. This is explained in way more detail than you can handle in the Virtual Box technical background

Accounts

Pick one of two ways to get an account:

• Ask the admin team (Mark Jenkins <mark@parit.ca> and Alex Weber)
• Use the automated claimid process for mumd at http://192.168.1.28 . mumd accounts are made available to the vmsrv host system via the wonders (and down sides) of LDAP.

Accounts are for Skullspace members only.

How to login and start VirtualBox

The host vm machine is 192.168.1.26. You can log in with a [[wikipedia:ssh|ssh] client (port 22) or RDP client (port 3389) if you're at the space. From the the space, ssh access is available on port 2222 and RDP on port 23389 courtesy of the Skullspace router (skullspace.markjenkins.ca, 206.220.196.50) .
(not the usual ports, configure your client! 22 and 3389 are reserved for mumd )

The default desktop environment is []wikipedia:LXDE | LXDE]] which is fairly lightweight, but still least has a menu in the corner and a task bar. VirtualBox can be found under the accessories menu.

Memory settings

The memory setting in virtual box is very important. Feel free to be more on the greedy side (1 gigabyte) if you're just starting your vm, doing your thing, and shutting it down when you're done (interactive use).

If you're planning on running all the time, than you need to be more on the low side like 256 megabytes. Keep in mind that any page swapping your guest operating system sends to your virtual "disks" is able to benefit from the host operating system allocated memory not used by programs to disk caching, so a little paging sometimes won't be that bad,,,. (a lot of paging, called thrashing most certainly will be)

Let everyone know how often you're using the VM service and what kind of RAM requirements you're hitting -- this will help us justify an upgrade to maximum RAM and eventually start fundraising for an even higher capacity machine.

Sound setting

Don't even bother, just disable the virtual sound card.

Network settings

We recommend using the bridged adapter instead of NAT. Join the skspprivbr bridge for the skullspace network and the skspvoipubbr bridge if you have a VOI public ip addresses allocated to you [[Networking |on the networking page].

Remote Access

We recommend installing guest operating systems with remote access features built in to them (such as any modern unix-like system and non cripled versions of Windows) and enabling these features shortly after completing your install.

This will allow you to go for direct logins to your virtual machine. You should also look into the commands for starting up VirtualBox "headless" -- once your vm is set up nicely you can probably do much faster starts and stops of it via ssh commands.

Always running VMs

The commands for starting and stopping VirtualBox "headless" are also very useful be used to start Virtual

libvirt

Eventually we would like to make allocation of linux containers and virtualbox possible via libvirt and manageable through nice tools like virt-manager.

libvirt has support for both of them, but we have to learn how to use it. virt-manager has some support but not for creating them to beging with, but it responds to command line stuff related to lxc and VirtualBox... and probably is okay once the underlying config files are in place...

Administrators

• Mark Jenkins <mark@parit.ca>
• Alex Weber