TurnKey Linux's take on Ubuntu appliance development: KISS

Andreas Heck aheck at gmx.de
Thu Jan 7 15:15:01 GMT 2010


Am Donnerstag, den 07.01.2010, 09:58 -0500 schrieb Forest Bond:
> I don't believe this is true.  Quoting from the Debian Policy Manual:
>   The Depends field should also be used if the postinst, prerm or postrm scripts
>   require the package to be present in order to run. Note, however, that the
>   postrm cannot rely on any non-essential packages to be present during the
>   purge phase.
> I think that this implies that a depended-upon package is guaranteed to be
> unpacked before executing the postinst script for the package with the
> dependency.  I assume that's where you'd run your configuration customization.

Yes, that has never been a problem when I experimented with building
appliances as packages. The moment your appliance package is being
installed and its maintainer scripts are run your depends packages are
already there.

Which leads to another problem because that means that if your depends
packages ask some questions which are totally stupid when used together
with the appliance package (e.g. your appliances pulls in phpMyAdmin and
apache2 to work together but phpMyAdmin asks if you want to use apache2
or lighttpd as webserver) your appliance package can't prevent them from
doing this. This is why I wrote a wrapper script around apt-get to first
pull in and apply a seed file corresponding to the appliance package.

Best regards,


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