Deploy Elastic Load Balancing in Amazon EC2-Classic

Amazon Web Services (AWS) lets you launch your instances in either Amazon EC2 or Amazon Virtual Private Cloud (Amazon VPC). If you've launched your instances in Amazon EC2, you will have to create a load balancer in Amazon EC2. If you've launched your instances with Amazon VPC, you will have to create your load balancer within the VPC. Elastic Load Balancing on Amazon VPC works mostly in a similar manner as in Amazon EC2 and supports the same set of features. There is however a significant difference between the procedures involved in launching a load balancer and the way security groups function on Amazon VPC and Amazon EC2.

This section walks you through the process of creating, accessing, and managing your load balancers in Amazon EC2. For information on creating, accessing, and managing your load balancers in Amazon VPC, see Deploy Elastic Load Balancing in Amazon VPC.

Elastic Load Balancing provides Secure Sockets Layer (SSL) support for connections between clients on the front-end and the load balancer and also for connections between the load balancer and your back-end application instances. If you choose HTTPS/SSL for your front-end connection, you can either use the pre-defined cipher set or use a cipher set of your choice to enable or disable the ciphers based on your specific requirements. If you choose to use an HTTPS/SSL connection for your back end, you can enable authentication on your back-end instance. For more information on configuring your load balancer to use cipher settings and for enabling authentication on your back-end instance, see Configure Listeners for Your Load Balancer . And for detailed instructions on creating a load balancer in Amazon EC2 with pre-defined cipher settings and enabling the back-end authentication, see Create a Load Balancer with SSL Cipher Settings and Back-End Server Authentication.

As the traffic to your instances increases, you might consider expanding your EC2 instances to run in an additional Availability Zone. For detailed instructions on expanding to additional Availability Zones, see Expand a Load Balanced Application to an Additional Availability Zone.

When the trafic to your instances decreases, you might consider scaling down the availability of your instances by disabling some Availibility Zones. For detailed instructions on disabling your Availability Zones, see Disable an Availability Zone from a Load-Balanced Application.

Elastic Load Balancing provides a special Amazon EC2 source security group that you can use to ensure that a back-end Amazon EC2 instance receives traffic only from Elastic Load Balancing. For information on locking the incoming traffic between your load balancer and your back-end instances , see Manage Security Groups in Amazon EC2-Classic.

After you create your load balancer, Elastic Load Balancing returns a public DNS name that combines your load balancer's name and region. This base public DNS name returns only IPv4 records.

Elastic Load Balancing supports both Internet Protocol version 6 (IPv6) and Internet Protocol version 4 (IPv4). IPv6 support is currently not available in all regions. For current IPv6 support, go to Elastic Load Balancing.

Clients can connect to your load balancer using either IPv4 or IPv6 (in regions where it is available). However, communication between the load balancer and its back-end instances uses only IPv4. You might want to use the dualstack-prefixed DNS name to enable IPv6 support for communications between client and the load balancers so that clients are able to access the load balancer using either IPv4 or IPv6 as their individual connectivity needs dictate. For more information on enabling IPv6 support, see Use IPv6 with Elastic Load Balancing.