Class: EC2_Utils

Inherits:
Object
  • Object
show all
Defined in:
lib/audit/lib/ec2_utils.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(ec2_options) ⇒ EC2_Utils

Returns a new instance of EC2_Utils.



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# File 'lib/audit/lib/ec2_utils.rb', line 7

def initialize(ec2_options)
	@ec2 = AWS::EC2::Base.new(ec2_options)
end

Instance Attribute Details

#ec2 ⇒ Object (readonly)

Returns the value of attribute ec2.



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# File 'lib/audit/lib/ec2_utils.rb', line 4

def ec2
  @ec2
end

Instance Method Details

#get_cheapest_instance_type(machine_id) ⇒ Object 



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# File 'lib/audit/lib/ec2_utils.rb', line 69

def get_cheapest_instance_type(machine_id)
	machines = @ec2.describe_images(:image_id => machine_id)
	begin
		return "t1.micro" if machines['imagesSet']['item'][0]['rootDeviceType'] == "ebs"
		return 'm1.small' if machines['imagesSet']['item'][0]['architecture'] == "i386"
		return "m1.large" if machines['imagesSet']['item'][0]['architecture'] == "x86_64"
	rescue => err
	end

	puts "ERROR: Finding cheapest instance type in EC2_Utils::get_cheapest_instance_type for machine_id = #{machine_id}"
	return "t1.micro"
end

#get_image_id(instance_id) ⇒ Object 



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# File 'lib/audit/lib/ec2_utils.rb', line 45

def get_image_id(instance_id)
	instances = @ec2.describe_instances(:instance_id => instance_id)
	if instances then
		return instances["reservationSet"]["item"][0]["instancesSet"]["item"][0]["imageId"]
	else
		return "none"
	end
end

#get_instance_public_dns(instance_id) ⇒ Object 



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# File 'lib/audit/lib/ec2_utils.rb', line 17

def get_instance_public_dns(instance_id)
	error_count = 0
	begin
		while (true) do
			instances = @ec2.describe_instances(:instance_id => instance_id)
			# protect against nil errors because parts of the structure are not initialized when the DNS is not known
			begin
				dns_name = instances["reservationSet"]["item"][0]["instancesSet"]["item"][0]["dnsName"]
				return dns_name if dns_name
			rescue => err
			end
			sleep(5)
		end
	rescue => err
		error_count += 1
		raise err if error_count > 3
		
		sleep(5)
		retry
	end
end

#get_instance_states ⇒ Object 



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# File 'lib/audit/lib/ec2_utils.rb', line 55

def get_instance_states()
	instanceStates = []
	@ec2.describe_instances()['reservationSet']['item'].each do|x|
		x['instancesSet']['item'].each do|y|
			instanceStates << {:instance_id => y['instanceId'], 
			                   :state => y['instanceState']['name'],
			                   :image_id => y['imageId'],
			                   :runtime => (DateTime.now() - DateTime.strptime(y['launchTime'], "%Y-%m-%dT%H:%M:%S")) * 24.0}
		end
	end
	return instanceStates
end

#get_instance_volumes(instance_id) ⇒ Object 



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# File 'lib/audit/lib/ec2_utils.rb', line 154

def get_instance_volumes(instance_id)
	volumes = []
	instances = @ec2.describe_instances(:instance_id => [instance_id])
	
	instances['reservationSet']['item'].each do|reservationSet|
		next unless reservationSet['instancesSet']
		
		reservationSet['instancesSet']['item'].each do|instancesSet|
			next unless instancesSet['blockDeviceMapping']
			
			instancesSet['blockDeviceMapping']['item'].each do|blockDeviceMapping|
				next unless blockDeviceMapping['ebs']
				
				volumes << blockDeviceMapping['ebs']['volumeId']
			end
		end
	end
	
	return volumes
end

#get_spot_prices(options = {}) ⇒ Object 



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# File 'lib/audit/lib/ec2_utils.rb', line 204

def get_spot_prices(options = {})
	arg = {:start_time => Time.now() - 1, :end_time => Time.now()}
	arg[:instance_type] = options[:instance_type] if options[:instance_type]
	spot_prices = ec2.describe_spot_price_history(arg)
	
	prices = {}
	if spot_prices["spotPriceHistorySet"] then
		spot_prices["spotPriceHistorySet"]["item"].each do|spot_price|
			(prices[spot_price["instanceType"]] ||= {})[spot_price["productDescription"]] = {:price => spot_price["spotPrice"], :timestamp => spot_price["timestamp"]}
		end
	end
	
	return prices
end

#start_instance(options) ⇒ Object 



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# File 'lib/audit/lib/ec2_utils.rb', line 83

def start_instance(options)
	raise "Invalid parameters to EC2_Utils::start_instance: :id is missing" unless options[:id]

	if /^ami-.*$/.match(options[:id]) then
		raise "Invalid parameters to EC2_Utils::start_instance: :ssh_keypair is missing" unless options[:ssh_keypair]
		raise "Invalid parameters to EC2_Utils::start_instance: :instance_type is missing" unless options[:instance_type]
		raise "Invalid parameters to EC2_Utils::start_instance: :security_group is missing" unless options[:security_group]
	
		instance_id = false
		if options[:max_price] then
			spot_request = @ec2.request_spot_instances(
				:image_id => options[:id], 
				:instance_count => 1, 
				:key_name => options[:ssh_keypair], 
				:security_group => options[:security_group], 
				:disable_api_termination => false, 
				:instance_type => options[:instance_type],
				:spot_price => options[:max_price],
				:valid_from => nil,
				:valid_until => nil)
				
			spot_request_id = spot_request['spotInstanceRequestSet']['item'][0]['spotInstanceRequestId']
			begin
				spot_reqs = ec2.describe_spot_instance_requests()
				spot_req = spot_reqs['spotInstanceRequestSet']['item'].reject{|x| x['spotInstanceRequestId'] != spot_request_id}
				
				raise "Spot request #{spot_request_id} seems to have disappeared" if spot_req.length() != 1
				
				if spot_req[0]['instanceId'] then
					instance_id = spot_req[0]['instanceId']
				end
				
				sleep(30)
			end until instance_id
		else
			instance = @ec2.run_instances(
				:image_id => options[:id], 
				:max_count => 1, 
				:key_name => options[:ssh_keypair], 
				:security_group => options[:security_group], 
				:disable_api_termination => false, 
				:instance_type => options[:instance_type])
			instance_id = instance["instancesSet"]["item"][0]["instanceId"] 
		end
		
		image_id = options[:id]                                                                                                                                                                                                                                                                                                                                                                                                                                                                          
	elsif /^i-.*$/.match(options[:id]) then 
		instance_id = options[:id] 
		image_id = get_image_id(instance_id) 
	else 
		raise "Unknown identifier #{options[:id]}"                                                                                                                                                                                                                                      
	end 

	puts "instance #{instance_id} started, waiting for IP address" if options[:verbose]
	begin 
		dns_name = get_instance_public_dns(instance_id) 
	rescue => err
		puts "ERROR: During DNS request of AMI" if options[:verbose]
	end
	
	if dns_name.nil? || dns_name.empty? then 
		puts "ERROR: No DNS name for AMI found" if options[:verbose]
		raise "No DNS name for AMI found"
	end
	
	return {:machine_id => image_id,
	        :instance_id => instance_id,
	        :public_dns => dns_name}
end

#terminate_instance(instance_id) ⇒ Object 



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# File 'lib/audit/lib/ec2_utils.rb', line 176

def terminate_instance(instance_id)
	volumes = get_instance_volumes(instance_id)
	
	@ec2.terminate_instances(:instance_id => [instance_id])

	begin
		#wait till instance is terminated
		begin
			instance_state = @ec2.describe_instances(:instance_id => [instance_id])['reservationSet']['item'][0]['instancesSet']['item'][0]['instanceState']['name']
		end unless instance_state == "terminated"
		
		#delete volumes
		volumes.each do|volume|
			begin
				@ec2.detach_volumes(:volume_id => volume)
			rescue => err
			end
			
			@ec2.delete_volume(:volume_id => volume)
		end
	rescue => err
		if err.class() == AWS::Error  && /The volume 'vol-[0-9a-f]{8}' does not exist/.match(err.message()) then
			#ignore error
		end
	end
end