Ruby on RailsからLambdaをキックしてOpsWorks管理のEC2を起動させる ref: http://qiita.com/horike37/items/9afe446ffc8478e46ee3

Lambdaのstart-incetanceファンクション

const ACCESS_KEY = '<ACCESS_KEY>';
const SECRET_KEY = '<SECRET_KEY>';

var AWS = require('aws-sdk');
AWS.config.update({accessKeyId: ACCESS_KEY, secretAccessKey: SECRET_KEY});

exports.handler = function(event, context) {
    var opsworks = new AWS.OpsWorks();
     opsworks.describeInstances( {InstanceIds : [event.instance_id]},function(err, data) {
        if (err) {
            console.log(err, err.stack);
        } else {
            if ( data.Instances[0].Status == 'stopped' ) {
                opsworks.startInstance({InstanceId : event.instance_id}, function(err, data) {
                    if (err) {
                        console.log(err, err.stack);
                    } else {
                        context.done(null, 'Update Online Success');
                    }
                });
            } else if ( data.Instances[0].Status == 'online' ) {
                context.done(null, 'Now Online');
            } else {
                context.done(null, 'Other Status');
            }
        }
    });
};

RailsのController

# coding: utf-8

class ItemsController < ApplicationController
  def index
    Aws.config[:region] = "us-east-1"
    lambda = Aws::Lambda::Client.new;
    if params[:instance_status_toggle]
      param = { instance_id: "<インスタンスID>"}.to_json # lambdaに渡す引数をjsonで生成
      resp = lambda.invoke_async(function_name: "start-incetance", invoke_args: param) # lambdaのstart-incetance関数を実行
    end
  end

end