This page contains technical notes about AWS networks
The following notes describe how Abiquo manages AWS networks in virtual datacenters with a Default private network or Custom private network, where Abiquo configures VPC networking Scenario 2.
When creating a NAT gateway, Abiquo will reuse floating IPs that are not assigned to a VDC.
VMs in private networks will have internet access through the public subnet.
Users can create public subnets and Abiquo will assign them to route tables with a route to the internet gateway.
When Abiquo creates new public subnets, it will not create any new NAT gateways.
If users delete the original public subnet, this will also delete the original NAT gateway. But Abiquo will replace all the routes in the main route table that route traffic to the deleted NAT gateway with a new rule to route traffic to the internet gateway.
Abiquo users must attach Elastic IPs to VMs with a connection to a public subnet.
Note that AWS may charge for Elastic IPs when they are NOT in use, i.e. when they are not assigned to a VM or when the VM is not deployed in AWS.
The private subnet is a private connect network.
To deploy to different Availability zones, create a private networks (VPC subnet) for each zone.
The private subnets in the same availability zone as a public subnet will have internet access through the public subnet.
Abiquo creates a VPC with a minimum network size of /16 and a subnet of size /24, or with the sizes defined by the user.
You can set a custom private network in Abiquo and this network will be used to create the VPC and subnet in Abiquo.
You can create multiple address spaces (called Abiquo address ranges) and Abiquo private networks in different availability zones in the same VPC.
AWS reserves the first four IP addresses and the last IP address of a VPC private connect network.
For a network that is defined to start with address 0, the first available IP address will be address 4 and the gateway address is address 1.
You can synchronize existing VMs and create new IP addresses through Abiquo, including multiple Elastic IPs.
The maximum number of IP addresses is determined by the AWS hardware profile (instance type). See https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-eni.html#AvailableIpPerENI
Abiquo adds IPs in the same subnet to the same elastic network interface.
For information about Elastic Network Interfaces, see https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-eni.html