APT tries to configure PostgreSQL each time I try to install a package

Question

I'm getting some strange errors lately whenever trying to apt-get install anything. Here's an example from trying to install fluidsynth.

$ sudo apt-get install libfluidsynth1
Reading package lists... Done
Building dependency tree       
Reading state information... Done
libfluidsynth1 is already the newest version.
libfluidsynth1 set to manually installed.
0 upgraded, 0 newly installed, 0 to remove and 1 not upgraded.
2 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Do you want to continue [Y/n]? y
Setting up postgresql-9.1 (9.1.10-0ubuntu12.04) ...
 * Starting PostgreSQL 9.1 database server                                                                                                                     * The PostgreSQL server failed to start. Please check the log output:
2013-11-03 14:21:42 EST FATAL:  could not access private key file "server.key": No such file or directory
                                                                                                                                                       [fail]
invoke-rc.d: initscript postgresql, action "start" failed.
dpkg: error processing postgresql-9.1 (--configure):
 subprocess installed post-installation script returned error exit status 1
dpkg: dependency problems prevent configuration of postgresql:
 postgresql depends on postgresql-9.1; however:
  Package postgresql-9.1 is not configured yet.
dpkg: error processing postgresql (--configure):
 dependency problems - leaving unconfigured
No apport report written because the error message indicates its a followup error from a previous failure.
                                                                                                          Errors were encountered while processing:
 postgresql-9.1
 postgresql
E: Sub-process /usr/bin/dpkg returned an error code (1)

I'm running 12.04. What's causing this and how do I address it? It happens for installing lots of things, and seems to suggest I need to initialize postgresql or something. I don't recall having fiddled with postgres, so I'm not sure why this suddenly became problematic.

Answer 1

Remove/purge postgresql-9.1 and reinstall them:

sudo apt-get --purge autoremove postgresql-9.1 postgresql

If you really use postgresql, or another package depends of it, you can install it again

sudo apt-get install postgresql the-other-program-that-got-removed

BTW, libfluidsynth1 is already installed, you don't need to install it again.

Answer 2

There's an even easier solution: Postgresql requires the "snakeoil" certificate to exist in order to run: /etc/ssl/private/ssl-cert-snakeoil.key If this was somehow deleted from your system, you can generate a new one with

# make-ssl-cert generate-default-snakeoil