[geeks] "Cloud" craziness...

[Patrick Giagnocavo]

On 4/3/2012 1:25 PM, Jonathan Katz wrote:
> Hey everyone!
> 
> Let's say I have a half-dozen virtual machines which I want to throw
> "in the cloud" so a team of folks spread across the globe can work on
> a few different programs which require individual OS instances. Having
> the hosting party worry about DR, backups, and availability would be
> nice.
> 
> Each OS/VM will likely be CentOS based.
> 
> What providers/bang for the buck, do you suggest? Joyent? Rackspace?
> 
> Alternately we're looking at co-locating a 2U box we'd own, but we'd
> like to avoid the headache of managing our own DR and worrying about
> bad disks.
> 
There are a lot of different ways to do it.

Given my experience with OpenVZ running Linux VMs, I would suggest you
look into using OpenVZ instead - actually, Proxmox.com's bundling of
OpenVZ along with a nice little Web GUI is pretty handy.  OpenVZ is
hands-down the most resource-friendly way to run a bunch of Linux VMs
(IMHO).

Plenty of providers offer colo + backup space.  You might find though
that the easiest option is to colo 2 boxes, and back the one up to the
other.

You don't mention how available you need to be.

If you want something fancier, you need at least 3 servers plus the
ability to shutdown each system, either with IPMI or an
Ethernet-connected power strip.  In this case, you have a quorum of 2
server that decide the other one is bad, the bad one gets turned off and
the VMs are booted off of shared storage on a second hardware node.

If your budget is low and 1 hour or so of downtime is acceptable, simply
colo 2 boxes, use RAID1 on all drives, and use DRBD to continuously
replicate changes from server A to server B. If server A gives problems,
start the VMs on server B.  Of course, you will need good backups, but
you should be well-connected enough to do offsite backups nightly.

Use LVM and you can snapshot the VMs easily enough, even while they are
online.


Hope this helps...

Patrick