Questions[cloud-computing](server)

I ran across this page in the Heroku docs...

Naked domains, also called bare or apex domains, are configured in DNS via A-records and have serious availability implications when used in highly available environments such as massive on-premise datacenters, cloud infrastructure services, and platforms like Heroku.

For maximum scalability and resiliency applications should avoid naked domains and instead rely solely on subdomain-based hostnames.

Does anyone here speak Enterprise? What are the "availability implications" they're warning about?

(I notice that http://stackoverflow.com works no problem, so evidently there are viable alternate philosophies on this issue.)

I am looking at automated deployment solutions for my team and have been playing with Chef for the past few days. I've been able to get a simple web app up an running from a base Red Hat VM using chef-solo.

Our end goal is to use Chef (or another system) to automatically deploy application topologies to the cloud as we run builds. Our process would basically run like this:

1. Our web app code, dependencies, and chef cookbooks are stored in SCM
2. A build is executed and creates a single package for images to acquire and test against
3. The build engine then deploys new cloud images that run a chef client to get packages installed.
4. The images acquire the cookbooks from SCM or the Chef server and install everything to get up and running

What are the benefits and/or use cases for getting a Chef Server running?

Are there any major benefits to have a Chef Server hold and acquire the cookbooks from SCM vs. using chef-solo and having a script that will pull the cookbooks from SCM?

This question is quite general, but most specifically I'm interested in knowing if virtual machine running Ubuntu Enterprise Cloud will be any slower than the same physical machine without any virtualization. How much (1%, 5%, 10%)?

Did anyone measure performance difference of web server or db server (virtual VS physical)?

If it depends on configuration, let's imagine two quad core processors, 12 GB of memory and a bunch of SSD disks, running 64-bit ubuntu enterprise server. On top of that, just 1 virtual machine allowed to use all resources available.

My company is moving our hosting to Amazon and I'm working though all the migration issues. It has been quite a challenge transitioning from physical hardware to transient virtual machines.

One of the last challenges is figuring out how to manage our EBS's and snapshots. Since their is no way currently to name them descriptively or add meaning, I'm wondering how admins are managing their resources. It's not too much of a problem with one or two servers, but how are those running multiple servers handling things. Is everyone using third party tools (like RightScale/Scalr) when they get over a handful of servers? Or are you maintaining wikis or other ancillary documentation?

I have an Amazon EC2 instance running and I will like to add another security group to that instance and then remove the current security group from that instance. Is this possible?