The following howto assumes that you are running Debian 7 (wheezy)

Stop Gitlab

service gitlab stop

Install postgresql

sudo apt-get install -y postgresql-9.1 postgresql-client libpq-dev

Initial Setup

The following initial setup was taken from installation.md from the main installtion doc

# Login to PostgreSQL
sudo -u postgres psql -d template1

# Create a user for GitLab.
template1=# CREATE USER git;

# Create the GitLab production database & grant all privileges on database
template1=# CREATE DATABASE gitlabhq_production OWNER git;

# Quit the database session
template1=# \q

# Try connecting to the new database with the new user
sudo -u git -H psql -d gitlabhq_production

Install postgres gem

cd ~git/gitlab
sudo -u git -H bundle install --deployment --without development test mysql aws

Dump the mysql database

Make sure you do this as root, and therefore you will also need the root password for mysql as well

mysqldump --compatible=postgresql --default-character-set=utf8 -r /tmp/gitlabhq_production.mysql -u root -p gitlabhq_production

Convert the mysql to postgres import

wget https://raw.github.com/lanyrd/mysql-postgresql-converter/master/db_converter.py -O /tmp/db_converter.py
python /tmp/db_converter.py /tmp/gitlabhq_production.mysql /tmp/gitlabhq_production.psql

Note: This was tested using debian 7, with python 2.7.3

Import the database

sudo -u git -H psql -d gitlabhq_production -f /tmp/gitlabhq_production.psql

Update database config

cd ~git/gitlab/config
sudo -u git -H cp database.yml database.yml.backup
sudo -u git -H cp database.yml.postgresql database.yml

The defaults from the database.yml should work if you have not made any modifications to the postgres authentication. You may need to change database.yml to suite your config.

Start Gitlab service

service gitlab start
service nginx restart

Check application Status

Check if GitLab and its environment are configured correctly:

cd ~git/gitlab
sudo -u git -H bundle exec rake gitlab:env:info RAILS_ENV=production

To make sure you didn't miss anything run a more thorough check with:

cd ~git/gitlab
sudo -u git -H bundle exec rake gitlab:check RAILS_ENV=production