Virtual Private Cloud — Networking Part 2

Note — Please checkout Part 1 if you are new to Virtual Private Cloud

In https://jigarr.medium.com/networking-in-amazon-web-services-7fc6d4afb926, I discussed various networking concepts at a high level for a Virtual Private Cloud. In this post, I want to explore on Elastic Network Interface, Elastic IP address and PrivateLink.

Virtualization has changed the industry in significant way. Virtual Machines provide on-demand disposable machines. Disk spaces are also virtualized so that you can attach/detach them on-demand. In the same way, network interface has been virtualized. It can be attached/detached at any point of time. This virtual network interface are called Elastic Network Interface (ENI).

Elastic Network Interface has some interesting use-cases

• Imagine one of your instances fails then ENI can be attached to a standby instance to rapidly recover the service (Hight Availability on budget)
• ENI has it’s own MAC address. Some commercial applications are tied to MAC address. You can license application with MAC address. Later on if application needs to run on a bulkier instance then you can do it with ease.
• More use cases can be found at https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/scenarios-enis.html

Let’s consider following scenario:

Connecting to AWS managed services

One common thing between AWS managed services such as S3, RDS and a Virtual Private Cloud created on AWS is both are deployed on AWS. One way to allow our Virtual Private Cloud to access AWS managed service would be via Internet Gateway. You can avoid going to Internet Gateway by setting up a PrivateLink as shown in following picture.

PrivateLink can be created by creating an Endpoint and attach it to subnet. Same endpoint can be attached to muliple subnets. Behind the scene, AWS would also create an Elastic Network Interface in each subnet.

Connect to AWS managed services through Endpoint

References

Elastic Network Interface — https://aws.amazon.com/blogs/aws/new-elastic-network-interfaces-in-the-virtual-private-cloud/

Use-case of ENI — https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/scenarios-enis.html

AWS PrivateLink Fundamentals — https://youtu.be/20RxEzAXG9o