Learn how to migrate your ruby-on-rails app from Heroku to Digital Ocean.

UPDATED VERSION IS HERE

Even thought this post is not directly related to IOT technologies, running a webserver/webapplication is often required. Running on Heroku can be quite expensive especially if the app is not getting as much traffic/revenues as expected.

Simple way:

First we need to add more swap memory:

sudo fallocate -l 2G /swapfile
sudo chmod 600 /swapfile

sudo mkswap /swapfile
sudo swapon /swapfile


echo '/swapfile none swap sw 0 0' | sudo tee -a /etc/fstab

You can check the swap space now (Optional):

free -h

Now let's install everything:

sudo apt-get update
command curl -sSL https://rvm.io/mpapis.asc | gpg --import -
curl -L get.rvm.io | bash -s stable
source /etc/profile.d/rvm.sh


rvm requirements
rvm install 2.4.1
sudo apt-get install -y libcurl4-openssl-dev nodejs
rvm rubygems current
gem install rails
gem install passenger
rvmsudo passenger-install-nginx-module

Install RVM:

From this tutorial

sudo apt-get install -y software-properties-common

sudo apt-add-repository -y ppa:rael-gc/rvm
sudo apt-get update
sudo apt-get install -y rvm 

Create a user :

You can follow this tutorial

• useradd appname_production

Add user to sudoers:

• usermod -aG sudo appname_production

Install postgresql:

From these notes : Creating user and adding access in Postgresql

• sudo apt-get -y install postgresql postgresql-contrib

Start postgres:

• sudo -u postgres psql

And run the following command

• createuser owning_user
• Exit postgres (CTRL-D)

Setting up the database:

SSH into your machine

From shell do :

• sudo -i -u postgres

• createuser --interactive
  
  Here you should follow the questions. You will have the following questions :

  • Enter name of role to add: user1
  • Shall the new role be a superuser? (y/n) y

• createdb appname_production

More info here:

Install PSQL for digital ocean

Copy database (if you have one already)

If you're migrating and have an existing database, here are the instructions. If not, then skip to next section.

Update the database with scp (from your mac):

• scp budata.sql root@serverip:/

Log into your user name :

• psql databasename < data_base_dump

Now we can access the database this way:

sudo -u appname_production psql

Change the password:

sudo -u appname_production psql

appname_production-# \password appname_production

Update the config/database.yml

Install RUBY 2.4.1:

rvm install ruby-2.4.1
rvm --default use ruby-2.4.1
gem install bundler --no-rdoc --no-ri
sudo apt-get install -y nodejs && sudo ln -sf /usr/bin/nodejs /usr/local/bin/node

Install rails :

Reference

gem search '^rails