Move Redmine Server whilst keeping external database - redmine

Question

I currently have redmine running on an nginx server. The actual MySQL database is on an external server and everything is working fine.
Now I would like to move it to an Apache Server on a different machine, ideally without changing/moving the database.
Is this possible, or do I always need to export/import the database regardless? Happy to stick with the same version of redmine (in my case 4.0.1., Ruby 2.5.1-p57, Rails 5.2.2, no plugins installed). If positive, what are the conditions on Ruby/Rails versions? Do they all have to be exactly what I had on the old one?

Answer 1

Database scheme is not affected by ruby version, only by Redmine's version, because new versions might add or remove stuff in database.
So in your case, copy-pasting your old Redmine to new server should work.
However you must ensure that new Redmine server (probably new IP) has proper privileges to access MySQL database.
And you must follow upgrade tutorial, because your new server needs to pull and install Ruby Gems, clear old cache from tmp folder etc...
https://www.redmine.org/projects/redmine/wiki/RedmineUpgrade

Answer 2

Aleksander's answers gave me confidence that it can be done, but I ended up persevering with my initial approach until I got that working rather than changing to his proposals.
I am afraid that I lost track of the sources for various bits, its primarily from the redmine help pages.
My complete solution was
sudo apt update
sudo apt upgrade
sudo apt install build-essential libmysqlclient-dev imagemagick libmagickwand-dev ruby-full
sudo apt install apache2 libapache2-mod-passenger
sudo gem update
sudo gem install bundler
sudo curl -L https://www.redmine.org/releases/redmine-4.0.1.tar.gz -o /tmp/redmine.tar.gz
sudo tar zxf /tmp/redmine.tar.gz
sudo mv redmine-4.0.1 /opt/redmine
sudo touch /opt/redmine/Gemfile.lock
sudo chown www-data:www-data /opt/redmine/Gemfile.lock
sudo chmod a+w /opt/redmine/Gemfile.lock
sudo cp /opt/redmine/config/database.yml.example /opt/redmine/config/database.yml
sudo ln -s /opt/redmine/public /var/www/html/redmine
cd /opt/redmine
mkdir -p /opt/redmine/app/assets/config && echo '{}' > /opt/redmine/app/assets/config/manifest.js
bundle install
bundle exec rake generate_secret_token
Note the manifest line above only applies to my particular redmine version which was incompatible with later sprockets versions. Also note that changing the permissions a+w is possibly excessive, but I struggled with permissions otherwise.
Then we have to do a few more manual tweaks. Open the file with your text editor:
sudo nano /opt/redmine/config/database.yml
and change production to be the following
production:
adapter: mysql2
database: myredminedatabasename
host: mysqlserver.somewhere.com
username: dbusername
password: "dbpassword"
encoding: utf8
Need to add the PassengerDefaultUser line to /etc/apache2/mods-available/passenger.conf (leave the other two lines the same even if slightly different)
<IfModule mod_passenger.c>
PassengerDefaultUser www-data
PassengerRoot /usr
PassengerRuby /usr/bin/ruby
</IfModule>
Change /etc/apache2/sites-available/000-default.conf to insert the following with the other sections so that apache knows to follow the symlink into Rails. Also note the first line setting DocumentRoot, which was oone of my personal stumbling blocks.
DocumentRoot /var/www/html/redmine
<Directory /var/www/html/redmine>
RailsBaseURI /redmine
PassengerResolveSymlinksInDocumentRoot on
</Directory>
We also need to copy the contents of files folder from /opt/redmine/files on older server to the new server in same location.
Also copy the email settings across in /opt/redmine/config/configuration.yml.
Then restart your server and it should be working.