List and reboot AWS instances using Client class

gistfile1.rb

require 'aws-sdk'
require 'json'

creds = JSON.load(File.read('creds.json'))
creds = Aws::Credentials.new(creds['AccessKeyId'], creds['SecretAccessKey'])

ec2 = Aws::EC2::Client.new(region:'us-west-1',credentials:creds)

instance_ids = []
ec2.describe_instances['reservations'].each do |reservation|
  reservation['instances'].each do |instance|
    puts "ID: #{instance.instance_id} State: #{instance.state.name} Hostname: #{instance.public_dns_name}"
    instance_ids.push instance.instance_id
  end
end

ec2.reboot_instances(instance_ids: instance_ids)