Synchronising jails

[Lowell Gilbert]

Frank Staals <frank at fstaals.net> writes:

> Hey Everyone,
>
> I'm looking for a way to synchronise two jails. More specifically, I
> would like to keep/maintain an exact copy of a given jail. As an
> example: Suppose I build a jail A on some system (in my particular case
> build with ezjail) , and I copy the jail
> into jail B on some other system (using tar, as is mentioned
> here: http://forums.freebsd.org/showthread.php?t=17813). Now stuff
> happens in Jail A, e.g. files change, new stuff is installed etc. I
> would like to propagate these changes to jail B, but since the transfer
> is over WAN I would like not to have to copy the entire jail again, just
> the stuff that has changed since the last backup. It is safe to assume
> nothing in Jail B changes: I basically want to maintain the exact copy
> so if something would happen to the system running Jail A I can
> immediately switch to jail B without much hassle. 
>
> Normally I would say this a perfect use case for rsync. But as the
> aforementioned thread mentions ``scp or similar wont work to copy a
> jail'', and I consider rsync similar to scp, I am under the impression
> that rsync would not be usable in this situation. Can anyone shed some
> light on this, or suggest an alternative to synchronise the jails?  

I didn't don't know of any problem with using rsync (over ssh) for this,
and after reading the thread to which you refer, I still don't.

Set up a testbed using rsync and see if it works for you. If it doesn't,
*then* you'll have something we can try to solve.