Ubuntu – Redmine 3.2.3-1 is half installed. Can neither be reinstalled nor removed

I'm running 16.04 LTS and I had the exact same problem, but I proceeded in a different way.

Remove Redmine

I didn't remove the dpkg scripts, but instead what I did was open the redmine.postrm script and comment the lines that caused the post removal script to crash, so my file was left like:

$ cat /var/lib/dpkg/info/redmine.postrm
#!/bin/sh

set -e

. /usr/share/debconf/confmodule
if [ -f /usr/share/dbconfig-common/dpkg/postrm ]; then
  . /usr/share/dbconfig-common/dpkg/postrm

  # remove both current and old instances
# START OF THE COMMENTED SECTION TO AVOID CRASHES 
#  instances=$(ls -1 /etc/redmine/*/database.yml | xargs dirname | xargs -n 1 basename)
#  for inst in $instances; do
#    dbc_go redmine/instances/$inst "$@"
#  done
# END OF THE COMMENTED SECTION TO AVOID CRASHES
fi

if [ "$1" = purge ]; then
  rm -rf /var/log/redmine
  rm -rf /var/cache/redmine
  rm -rf /var/lib/redmine
  rm -rf /etc/redmine
fi

## Automatically added by dh_installdebconf
if [ "$1" = purge ] && [ -e /usr/share/debconf/confmodule ]; then
    . /usr/share/debconf/confmodule
    db_purge
fi
# End automatically added section
#

Which allowed me to simply remove it with:

sudo apt-get remove redmine --purge

It will prompt you asking you if you want to delete the database redmine_default; I answered yes, but you should choose carefully.

After that it will purge all your installation with no warnings, so your first question is answered.

(To have more information about how dpkg scripts works, please have a look at: https://www.debian.org/doc/debian-policy/ch-maintainerscripts.html)

Reinstall Redmine

Now, how to install redmine and getting it running?

We'll start by doing

sudo apt-get update && sudo apt-get install redmine redmine-mysql

Probably it will crash again saying something like:

Configurando redmine (3.2.1-2) ...
Determining localhost credentials from /etc/mysql/debian.cnf: succeeded.
dbconfig-common: writing config to /etc/dbconfig-common/redmine/instances/default.conf
Not replacing deleted config file /etc/redmine/default/database.yml
granting access to database redmine_default for redmine/instance@localhost: already exists.
creating database redmine_default: already exists.
dbconfig-common: flushing administrative password
rake aborted!
Cannot load 'Rails.application.database_configuration':
Could not load database configuration. No such file - ["/usr/share/redmine/instances/default/config/database.yml"]
/usr/share/redmine/lib/plugins/acts_as_activity_provider/init.rb:2:in 'block in <top (required)>'
/usr/share/redmine/config/initializers/00-core_plugins.rb:12:in 'eval'
/usr/share/redmine/config/initializers/00-core_plugins.rb:12:in 'block in <top (required)>'
/usr/share/redmine/config/initializers/00-core_plugins.rb:2:in 'each'
/usr/share/redmine/config/initializers/00-core_plugins.rb:2:in '<top (required)>'
/usr/share/redmine/config/environment.rb:14:in '<top (required)>'
/var/lib/gems/2.3.0/gems/rake-11.3.0/exe/rake:27:in '<top (required)>'
/var/lib/gems/2.3.0/gems/bundler-1.13.1/lib/bundler/cli/exec.rb:74:in 'load'
/var/lib/gems/2.3.0/gems/bundler-1.13.1/lib/bundler/cli/exec.rb:74:in 'kernel_load'
/var/lib/gems/2.3.0/gems/bundler-1.13.1/lib/bundler/cli/exec.rb:27:in 'run'
/var/lib/gems/2.3.0/gems/bundler-1.13.1/lib/bundler/cli.rb:332:in 'exec'
/var/lib/gems/2.3.0/gems/bundler-1.13.1/lib/bundler/vendor/thor/lib/thor/command.rb:27:in 'run'
/var/lib/gems/2.3.0/gems/bundler-1.13.1/lib/bundler/vendor/thor/lib/thor/invocation.rb:126:in 'invoke_command'
/var/lib/gems/2.3.0/gems/bundler-1.13.1/lib/bundler/vendor/thor/lib/thor.rb:359:in 'dispatch'
/var/lib/gems/2.3.0/gems/bundler-1.13.1/lib/bundler/cli.rb:20:in 'dispatch'
/var/lib/gems/2.3.0/gems/bundler-1.13.1/lib/bundler/vendor/thor/lib/thor/base.rb:440:in `start'
/var/lib/gems/2.3.0/gems/bundler-1.13.1/lib/bundler/cli.rb:11:in 'start'
/var/lib/gems/2.3.0/gems/bundler-1.13.1/exe/bundle:34:in 'block in <top (required)>'
/var/lib/gems/2.3.0/gems/bundler-1.13.1/lib/bundler/friendly_errors.rb:100:in 'with_friendly_errors'
/var/lib/gems/2.3.0/gems/bundler-1.13.1/exe/bundle:26:in '<top (required)>'

Recreate database.yml

Where it clearly states that it

Could not load database configuration. No such file - ["/usr/share/redmine/instances/default/config/database.yml"]

Now we have 2 options:

Create one

For the 3.2 version you can find an example here: http://www.redmine.org/projects/redmine/repository/entry/branches/3.2-stable/config/database.yml.example. After a minor changes we can have something like:

cat /usr/share/redmine/instances/default/config/database.yml
# Setup is given for MySQL with ruby1.9.    
# Examples for PostgreSQL, SQLite3 and SQL Server can be found at the end.    
# Line indentation must be 2 spaces (no tabs).

production:    
  adapter: mysql2
  database: redmine_default
  host: localhost    
  username: root    
  password: "MySQLRootPassword"    
  encoding: utf8    
development:    
  adapter: mysql2    
  database: redmine_default
  host: localhost    
  username: root    
  password: ""
  encoding: utf8    
# Warning: The database defined as "test" will be erased and
# re-generated from your development database when you run "rake".    
# Do not set this db to the same as development or production.    
test:    
  adapter: mysql2    
  database: redmine_test    
  host: localhost    
  username: root    
  password: ""    
  encoding: utf8

Be careful as the production database HAS TO BE redmine_default or at least is the one that is left created after installation. I didn't check whether it will work with another value.

Copy the one that was created during installation

You could move it where the configuration script is trying to find it:

sudo cp /usr/share/redmine/config/database.yml /usr/share/redmine/instances/default/config/database.yml

Now that we have all that you need, we can finish the install with:

sudo apt-get -f install 

Further information about installing redmine on Ubuntu is in this wiki in redmine.com.