AWS Official Blog

New – AWS Elastic Load Balancing Inside of a Virtual Private Cloud

by Jeff Barr | on | in Amazon EC2, Amazon Elastic Load Balancer, Amazon VPC |

The popular AWS Elastic Load Balancing Feature is now available within the Virtual Private Cloud (VPC). Features such as SSL termination, health checks, sticky sessions and CloudWatch monitoring can be configured from the AWS Management Console, the command line, or through the Elastic Load Balancing APIs.

When you provision an Elastic Load Balancer for your VPC, you can assign security groups to it. You can place ELBs into VPC subnets, and you can also use subnet ACLs (Access Control Lists). The EC2 instances that you register with the Elastic Load Balancer do not need to have public IP addresses. The combination of the Virtual Private Cloud, subnets, security groups, and access control lists gives you precise, fine-grained control over access to your Load Balancers and to the EC2 instances behind them and allows you to create a private load balancer.

Here’s how it all fits together:

When you create an Elastic Load Balancer inside of a VPC, you must designate one or more subnets to attach. The ELB can run in one subnet per Availability Zone; we recommend (as shown in the diagram above) that you set aside a subnet specifically for each ELB. In order to allow for room (IP address space) for each ELB to grow as part of the intrinsic ELB scaling process, the subnet must contain at least 100 IP addresses (a /25 or larger).

We think you will be able to put this new feature to use right away. We are also working on additional enhancements, including IPv6 support for ELB in VPC and the ability to use Elastic Load Balancers for internal application tiers.

– Jeff;