From 2.9 to 3.0

1. Stop server & resque

sudo service gitlab stop

2. Follow instructions

# Get latest code
git pull origin stable

# Install gems
bundle install --without development test

# Migrate db
bundle exec rake db:migrate RAILS_ENV=production

# Make some changes to gitolite config
# For more information visit https://github.com/gitlabhq/gitlabhq/pull/1719
sudo -u git -H sed -i "s/\(GIT_CONFIG_KEYS\s*=>*\s*\).\{2\}/\1'\.\*'/g" /home/git/.gitolite.rc

# Check APP Status
bundle exec rake gitlab:app:status RAILS_ENV=production

Compare your config/gitlab.yml & config/gitlab.yml.example for new settings

Especially for LDAP

3. Start all

sudo service gitlab start