Abiquo AWS integration networking changes

In the AWS integration, Abiquo 4.0 creates VPCs with a different network configuration, providing NAT support with a public subnet, and also allowing virtual machines on different subnets to be connected to the same load balancer. Abiquo now supports the AWS gateway address as the first address in the network.

Abiquo now configures VPC networking Scenario 2 as described in the AWS documentation http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_Scenario2.html.
Under this configuration, users must attach Elastic IPs to virtual machines with a connection to the public subnet. And by default, virtual machines in private networks will have internet access through the public subnet. This is helpful for automation because a virtual machine can now connect to the internet to download its configuration, for example, using Chef, without its own Elastic IP.

During the upgrade, Abiquo does not make any changes to existing VPCs. When users synchronize VPCs, Abiquo will detect a public subnet by the presence of a custom route table and NAT gateway, and Abiquo will mark the public subnet. Users with bespoke network configurations should check the results of the synchronization.

When Abiquo creates a VPC, it creates the default private network (subnet) and a default public subnet, using the next available network address. The administrator can supply a subnet mask in the Abiquo configuration properties. When users create additional private networks, Abiquo adds them to the main route table, allowing outbound internet access.

Abiquo marks the default network with a star and the public subnet with a globe symbol. The Internet gateway flag is set for the public subnet.

In previous versions of Abiquo, the virtual machines connected to a load balancer had to be located in the same subnet as the load balancer, and in Abiquo v4.0 this restriction has been removed for the AWS integration. As a result of this change, users can create a load balancer in the public subnet to balance across virtual machines in private subnets. 

See AWS Integration