Deploying a Rails 5 app to EC2- RDS DB Instance connectivity error

Question

I have created DB instance and gone through the config process of aws rds instance as per the documentation. created an instance of db successfully. also changed the connection params in database.yml accordingly. I ran the following commands in ngnix server installed on ubuntu 16.04 at aws and also rebooted the db instance several times.

RAILS_ENV=production rake db:create

and db created successfully and then ran

RAILS_ENV=production rake db:migrate

and database migrated successfully. an then ran the command sudo service nginx restart after all of the process when I am visiting my app its says

 PG::ConnectionBad could not connect to server: Connection refused Is the server running on host "localhost" (127.0.0.1) and accepting TCP/IP connections on port 5432? 

here is my database.yml

development:
  host: localhost
  database: ups_developement_db
  adapter: postgresql
  encoding: unicode
  port: 5432
  username: postgres
  password: postgres
production:
  host: dbcustom.cjocvmnblsa4.us-east-2.rds.amazonaws.com
  database: ups_db
  adapter: postgresql
  encoding: unicode
  port: 5432
  username: dbmasteruser
  password: dbmasterPassword

I am open to provide any kind of information required. Thanks a lot for your time and solution in advance

Answer 1

It's almost certain that you have not configured the security groups on the RDS instance correctly.

Log into your EC2 and issue the command

telnet <rds hostname> 5432

You should see something like

Trying 10.1.1.2...
Connected to 10.1.1.2.
Escape character is '^]'.

which means that TCP can flow between your EC2 and your RDS.

If not, you need to permit your EC2 to connect to your RDS instance by adding the correct security group configuration.

Answer 2

You should create Environment variables in your AWS RDS instance you should use them in your rails app config file. Check here

database.yml should look like this

production:
  adapter: mysql2
  encoding: utf8
  database: <%= ENV['RDS_DB_NAME'] %>
  username: <%= ENV['RDS_USERNAME'] %>
  password: <%= ENV['RDS_PASSWORD'] %>
  host: <%= ENV['RDS_HOSTNAME'] %>
  port: <%= ENV['RDS_PORT'] %>