This article will describe the way I set up a Rails app with ElasticBeanstalk and PostgresSQL. Here Rails 4.1 based on Puma 2.10.2 and Nginx 1.6.2 is demonstrated.

Install ElasticBeanstalk CLI

AWS provides both Management Console and EB CLI to work with ElasticBeanstalk.

The CLI requires python and is easier to perform some features of ElasticBeanstalk.

pip install awsebcli

Create an IAM user

ElasticBeanstalk will require an IAM user to create app environment. In case you have no idea how to create an IAM user, please view this post.

Initialize a git repository

Here agileorder is the name of my app.

$ cd agileorder
$ git init
$ git add -A
$ git commit -m "Initial commit"

Initialize EB environment

$ eb init

Select a default region
1) us-east-1 : US East (N. Virginia)
2) us-west-1 : US West (N. California)
3) us-west-2 : US West (Oregon)
4) eu-west-1 : EU (Ireland)
5) eu-central-1 : EU (Frankfurt)
6) ap-southeast-1 : Asia Pacific (Singapore)
7) ap-southeast-2 : Asia Pacific (Sydney)
8) ap-northeast-1 : Asia Pacific (Tokyo)
9) sa-east-1 : South America (Sao Paulo)
(default is 3): 8

Select an application to use
1) [ Create new Application ]
(default is 1): 1

Enter Application Name: agileorder

It appears you are using Ruby. Is this correct?
(y/n): y

Select a platform version.
1) Ruby 2.2 (Puma)
2) Ruby 2.1 (Puma)
3) Ruby 2.0 (Puma)
4) Ruby 2.2 (Passenger Standalone)
5) Ruby 2.1 (Passenger Standalone)
6) Ruby 2.0 (Passenger Standalone)
7) Ruby 1.9.3
(default is 1): 2
Do you want to set up SSH for your instances?
(y/n): n

Please note that eb init will add .elasticbeanstalk to the .gitignore. Be sure to commit .gitignore once again.

$ git add .gitignore
$ git commit -m "Update .gitignore"

Configure EB to install postgresql-devel

Under project directory, create .ebextensions/packages.config with following content.

{% codeblock .ebextensions/packages.config lang:yaml %} packages: yum: postgresql93-devel: []

Then add the .ebextensions to repository

git add .ebextensions
git commit -m "Add .ebextensions"

Create environment

$ eb create agileorder-env

After waiting for a while, the last part of output messages are shown as

INFO: Application available at agileorder-env-jmcrf7dbdr.elasticbeanstalk.com.
ERROR: Create environment operation is complete, but with errors. For more information, see troubleshooting documentation.
INFO: Adding instance 'i-72db7287' to your environment.

After checking logs, I figured out the errors come from the missing environment variables used in my app.

Set up environment variables

Under Software Configuration of Elastic Beanstalk of AWS Management Console, add essential environments used in app like SECRET_KEY_BASE, SENTRY_DSN, ...etc.

Create a RDS instance

Under Data Tier of Elastic Beanstalk of AWS Management Console, create a new RDS database and set the DB engine to postgres.

After setting Master Username and Master Password, then click Save, environment variables will have been added to EB environment automatically.

Configure database.yml to work with RDS instance

Under project directory, modify the database.yml as

config/database.yml:

... skip the parts of development and test modes ...

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

Commit the database.yml to repository

git add -A
git commit -m "Update database.yml"

Finally, deploy the app to AWS.

eb deploy

To open the app URL in a browser, simply execute

eb open