[lug] duping minimal vm question

[David Ahern]

On 06/03/10 09:57, karl horlen wrote:
> i didn't want to hijack the other recent thread but came across this nugget which i've been contemplating myself recently for a different purpose.
> 
>>> Maybe you could setup a virtual machine per client on
>> the data fetch server
>>> to provide more isolation. Depends on how many
>> clients. With a known
>>> transfer schedule, the VMs don't even have to run all
>> the time.
> 
> i haven't decided which virtual manager to use yet but i'd like to roll out a server which isolates one vm per client.  each client would basically need a minimal lamp stack for a website but nothing else.  i want to keep it as simple as possible. questions:
> 
> - what's the best way to install a minimal centos install on a "master" client / guest vm?
> 
> - once i have that master guest, is it possible to simply use it to dup multiple future guests based on teh master?  if so, how easy is it?  
> 
> - i'm also wondering how many vm guests i can realistically expect to rollout on this server before performance suffers?  i know that's going to be fairly subjective based on the performance requirements of each guest website so guess i'm on my own here.  anybody have a formula / method to estimate usage to quantify this before setting up the vm guests?
> 
> fwiw, i imagine each virtualization implementation has it's own method[s] so i don't need specifics unless you want to share, especially since i haven't picked my vm implementation yet.  but if you feel one VM is generally better than another overall or at guest vm duping per scenario above, info appreciated.

ESX is costly, but does have a polished finish. Kind of like Apple
products - you pay for the glitz. I personally find the GUI's for ESX
slow, constraining and frustrating.

I've been using KVM for almost 3 years now. Sans GUI (ie., using the
command line) it has a bit of a learning curve -- most notably with the
networking setup. Once that piece clicks you can realize the power and
flexibility of this path.

There is a copy-on-write option for images, but it is debatable as to
its worthiness and stability. As an alternative you can have a master
image and use cp (recommended with the --sparse option) to make copies
for individual VMs. For instance, put the OS on one virtual disk and
data on a second. You can update the OS image as you need.

With KVM VM's are just another process so you can use a variety of linux
tools to set priority's and limit resource consumption (e.g., cgroups).

David


> 
> thanks
> 
> 
>       
> _______________________________________________
> Web Page:  http://lug.boulder.co.us
> Mailing List: http://lists.lug.boulder.co.us/mailman/listinfo/lug
> Join us on IRC: irc.hackingsociety.org port=6667 channel=#hackingsociety