Design question: how to create installation package to cover all cases
 

Embedded system running ubuntu, this system is a blackbox to the user, you
can use web to see its status, but no console outputs until developers fly
there.

My design question is a general question, not for ubuntu only.

we want to build the installation package for our application,
each time user installs the new package in the running system, it's a black
box to them. Our installation should cover all kinds of cases.

Things i can think of:
1. what's the best/standard package creation procedure for ubuntu 12.04 ?
any website ?
seems there're different ways from web.

2. if this time my app is ver 1.1, next time it'll be 1.2, where to put
this version info ?

3. if this board will be in the field for 20 years, will never come back,
once a while we can install new kernel/file system/app in it, how to make
sure this install can always work ? (think about windows update, things can
get messed up, certain app version won't work with certain kernel/fs etc.) should be a dependency somewhere ?

4. what happens if in the middle of install, the board lost power, how to
make sure it can still come back online when power is back ?

5. how to do rollback ? assume apt-get/dpkg has some commands ?

Many thanks !

I suggest that you set up 2 software systems on the device and dual boot. When you update a system only do one system at a time. That way you can fall back on the other system if an upgrade goes badly wrong. You would also have to build in a way to fix a broken system from the good system.

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Steve Stites