[Openstack-devel] Bug#677400: Bug#677400: This is not a bug, it is a feature!

[Thomas Goirand]

On 06/19/2012 12:43 AM, ghe. rivero wrote:
> Hi everyone,
>    i finally managed to find the problem (not uploaded a fix, but it's
> pretty trivial).  As Zigo noted, scripts shouldn't change conffiles,
> but in our case, as we are using dbconfig, if we use other options
> than the defaults ones, it's ok to do it. In our case, using the
> default options (or non-interactive as piuparts does) the problem is
> that in nova-common.postinst script (line ~81)
>      SQL_CONNECTION="sqlite:////$dbc_basepath/$dbc_dbname"
>  we add an extra / (slash) after sqlite,  making the conf file
> different than the package default provided. The solution is as eassy
> as remove one the /. I'll wait for comments to provide a fix for it.
> 
> Ghe Rivero

Hi Ghe!

The issue isn't only with the default. That's not the way to fix. The
file shouldn't be marked as conffile, and that's it.

We should allow everyone to upgrade from one version to another, without
prompting anything to the user if the user didn't edit anything in the
config file. That's basically what the policy tells.

If let's say, the user decides to use MySQL when configuring the package
using debconf, then later on upgrade his nova-common package, then we
really don't want dpkg to prompt the user about new stuff in the config
file. Especially considering that the user may decide to overwrite the
file, which may potentially break his configuration.

Also, the policy tells that we *must* read the configuration from the
configuration file in the debian/nova-common.config. That is: if the
user edits /etc/nova/nova.conf and decides, for some reason, let's say
to switch from sqlite to mysql, we should be able to detect that, and
have dbconfig-common catch up with it. Currently, it's quite hard to do,
because dbconfig-common cannot be preseed easily. So again, currently,
that has to be done, because our package isn't policy compliant.

I'm really not sure how to fix this issue. I don't think parsing
/etc/nova/nova.conf to find out what values are in would be hard, but
I'm really not sure how to preseed stuff in dbconfig-common. Ghe, could
you explain to me how to do dbconfig-common preseed, and what's the
format of the files in /etc/dbconfig-common/? It's currently a bit
cryptic to me.

So, anywa, what we should do (and what I did) is: we don't ship a
/etc/nova/nova.conf in the nova-common package, and create it when the
postinst script is ran. For this, I've put it in
/usr/share/doc/nova-common/nova.conf.dist. This in our Git repository
right now.

Please note that the release team agrees with me, and that I had such
issues in the past, so I believe I'm right.

Thomas