[Lxc-users] Containers in NFS, or ...

[Matto Fransen]

Hi,

On Thu, Jul 21, 2011 at 06:02:09PM +0100, Gordon Henderson wrote:

> A few months ago there were some posts about running containers in a 
> diskless host - just looking for some more info about this in my ponderous 
> ponderings!
> 
> I'm not after having a diskless host (although it's an option), but to 
> have a host NFS mount a filesystem of a container, then start it....
> 
> ie. big NFS servery type thing. Many front-end hosts with lots of RAM, but 
> minimal disks. Container image NFS (or ?) mounted off server. Lets assume 
> 2 LAN interfaces on the fronting server - a private one to the filestore 
> and a public one to the rest of the world... (although that's not critical 
> for what I'm thinking of)
> 
> That would then make management of the images utterly trivial and give the 
> ability to migrate them from one physical host to another with nothing 
> more than a shutdown/de-config on one host, and a config/startup on a new 
> host...
> 
> However, assuming LXC is happy with it, there's the issue of running 
> services on an NFS server - but that's really not something for here - I'm 
> just interested in the scenario of server + multiple hosts... mounting 
> images via NFS. I can't think why it might not work... Obviously there 
> might be performance issues, but lets assume the environment is mostly 
> read access of a typical LAMP type server (with the M part on another 
> separate server using standard MySQL network access to it, rather than 
> local access to the (NFS) disk)
> 
> This is basically a managemnt type issue more than anything else - the 
> ability to migrate containers to faster/less loaded hosts, or failled 
> hosts and so on. (Lets assume the file and sql servers are adequately 
> backed up by other means)
> 
> Anyone see any issues? Would anyone do it differently?

Well, you could also use iscsi in stead of nfs ...

Also, some time ago I have build -as a proof of concept, but mostly just
for fun- a bootable USB-stick with a kernel, busybox, some other stuff
and LXC. 
The usb-stick contains a small Linux system that is capable of starting
LXC-containers. So you let some system boot from this USB-stick. The
system provides a NIC and the harddisks. This would come close to what
you describe: a config-free server that only provides storage (and 
in this case: network-connection) and a small environment that 
contains as little as possible but provides the functionality to
manage and start LXC-containers. 

Open source software gives us so much fun :)

Cheers,

Matto