unionfs limitations?

[George Hartzell]

Eirik Øverby writes:
 > Hi,
 > 
 > I just started playing with mounting ports into jails using unionfs
 > (mount_unionfs -b /usr/ports_jail /usr/local/jails/jail-0/usr/ports), and
 > many things seem to work fine.
 > However, when trying to install either of mysql41-server or mysql41-client,
 > I see the following:
 > 
 > [root at mpi1] /usr/ports/databases/mysql41-server# make install
 > ===>  Installing for mysql-server-4.1.11_1
 > ===>   mysql-server-4.1.11_1 depends on shared library: mysqlclient.14 -
 > found
 > ===>   Generating temporary packing list
 > ===>  Checking if databases/mysql41-server already installed
 > ln: POSIX: Operation not supported
 > *** Error code 1
 > 
 > Stop in /usr/ports/databases/mysql41-server.
 > 
 > Did I miss out on something, or is this not going to work? Do I need to
 > think in other ways?
 > [...]

Here's one unionfs/jail gotcha that's bitten me a couple of times.  If
you actually *use* (or, have used) the ports directory to build and
install stuff onto the "host" machine, the ports infrastructure in the
jail gets kind of confused.  It seems to be checking for the files in
the dependencies, doesn't find them, goes to make them, and then
[depending on what state the relevant port directory is in], things
get "odd".

I've started just using a virgin ports tree as the underpinnings for
my unionfs'ed jails.

Is there any chance that you've installed mysql-server on the host?

g.