Virtualization Within Virtualization? Vmware -> OpenVZ?

[Reece-DM]

Hi,

Well I remember seeing the fiasco with some tom dick or a harry stating a provider was using this technique with their production servers, as I know  Vmware allows memory ballooning which shares the same memory between certain processes per VM which in effect could benefit over sellers running OVZ inside of it.

So regardless of all that, how well do you think it would perform? Its does provide benefits for redundancy and being able to backup/moves instantly with a sort of cloud feel thanks to Vmware?. But how well do you think performance would hold up?

There's been rumours, but I can't actually find anything to related to how it would perform.

Reece.

 

[KuJoe]

I do all of my development on ESXi hosts and the majority of my development is for OpenVZ so I run a handful of OpenVZ nodes as VMware VMs. Then again, the loads are minimal and the servers aren't using RAID so I cannot comment on performance for a production node but I can say I haven't seen a performance hit between VMware -> OpenVZ versus Bare metal -> OpenVZ on similar hardware.

 

[JDiggity]

cue @Francisco as this was a tactic of BuyVM when they first started I believe.  Correct me if I am wrong.  Fran can explain it in full detail and how it works.  I think fran did run into some issues with it.

 

[imperio]

I remember discussing this implementation on LET with some concerns.

http://lowendtalk.com/discussion/10300/the-truth-about-buyvm-and-its-shilling/p6

 

[Francisco]

cue @Francisco as this was a tactic of BuyVM when they first started I believe.  Correct me if I am wrong.  Fran can explain it in full detail and how it works.  I think fran did run into some issues with it.

Yep, and it failed horribly The original plan was to get a nice SAN in place and be able to hot migrate whole nodes when we needed to do hardware maintenance. It's pretty damn ugly to do HA with openvz otherwise so this was our brilliant idea to get around NFS shares and vzmigrate.

Even w/ ballooning turned off vmware was a total mess. You have to run 'vmtools' to make the VM perform well but the problem is the drivers don't stay 'loaded'. Even on the desktop version of vmware if you let a VM idle for a while then come back to it? It'll be tanked and require a vmtool restart.

It was a good idea on paper but didn't work in the end.

Francisco

 

[Reece-DM]

Yep, and it failed horribly The original plan was to get a nice SAN in place and be able to hot migrate whole nodes when we needed to do hardware maintenance. It's pretty damn ugly to do HA with openvz otherwise so this was our brilliant idea to get around NFS shares and vzmigrate.


Even w/ ballooning turned off vmware was a total mess. You have to run 'vmtools' to make the VM perform well but the problem is the drivers don't stay 'loaded'. Even on the desktop version of vmware if you let a VM idle for a while then come back to it? It'll be tanked and require a vmtool restart.


It was a good idea on paper but didn't work in the end.


Francisco

I appreciate your time in telling us about your venture with this idea.

What issues did you face? And what about your trials of XEN?

 

[ComputerTrophy]

Wouldn't it be immediately obvious, that running a container inside a container will have performance issues?

 

[Francisco]

I appreciate your time in telling us about your venture with this idea.

What issues did you face? And what about your trials of XEN?

We used XEN for internal stuff, namely our old SQL box. It ran fine but I hated citrix's client. It's really annoying, requires windows, and there really was no reason to keep it like that. In the end we've moved our SQL's onto dedicated internal OVZ nodes to make big migrations easy. Migrating cpanel based boxes is a pain in the ASS so vzmigrate makes life really easy.

Wouldn't it be immediately obvious, that running a container inside a container will have performance issues?

Sure. It takes a lot of work to make KVM not suck when you're throwing a ton of work load at it.

Francisco

 

[splitice]

I have a similar setup with OpenVZ in KVM. I don't know about its performance or stability (outside of a few basic tasks) really though, its only used for mass testing a couple of daemons over a virtual network.