Configuration files for EC2 for using node.js (e.g. NODE_ENV = production)

On Elastic Beanstalk, it is possible to set the environment

option_settings:
  - namespace: aws:elasticbeanstalk:container:nodejs:staticfiles
    option_name: /public
    value: /public
  - option_name: NODE_ENV
    value: production

and also access the variables in the node/express, for e.g.

console.log('Using production settings.');
app.set('connection', mysql.createConnection({
  host: process.env.RDS_HOSTNAME,
  user: process.env.RDS_USERNAME,
  password: process.env.RDS_PASSWORD,
  port: process.env.RDS_PORT}));

Now, if I have to do the same on EC2 (without using Elastic Beanstalk)

1. How/where do I set these environment variables
2. How can I access them