Tag Archives: AWS PrivateLink

Scaling with AWS PrivateLink

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In this article, we’ll discuss the scalability aspects of AWS PrivateLink. We’ll examine how the expansion of the service consumer VPC count impacts AWS PrivateLink implementation and its management. Additionally, we will delve into key considerations for designing a scalable solution using AWS PrivateLink.

Scale with AWS PrivateLink

AWS PrivateLink Primer

AWS PrivateLink provides a method for making your service accessible to other VPCs through a secure, private network connection over the AWS backbone network. This ensures that your data remains within the AWS network, thereby improving security and lowering data transfer expenses compared to when utilizing the public internet. The basic architecture of AWS PrivateLink is depicted as follows –

AWS PrivateLink architecture

To set up the connection, you must establish an Endpoint Service within the service provider VPC, using a network/gateway load balancer. In the service consumer VPC, you should create a VPC endpoint that links to this Endpoint Service. The endpoint policies facilitate access control by specifying which principles are permitted to connect to the Endpoint Service. Please refer to this AWS documentation for more details.

Scalability aspect

Now, let’s discuss the scalability aspect concerning AWS PrivateLink. When we talk about scalability, we’re referring to the expansion of the number of VPCs acting as service consumers. In scenarios where you have critical or shared services hosted within the service provider VPC and made accessible through AWS PrivateLink for consumption by services located in different VPCs, it’s clear that the count of consumer VPCs will keep increasing. Therefore, it becomes essential to take scalability considerations into account.

Various VPC endpoints situated in different consumer VPCs can establish connections with a single endpoint service located in the service provider VPC. Hence, you can think of a high-level architecture as below –

Multiple VPC endpoints to one endpoint service

Furthermore, it’s important to note that AWS PrivateLink can enable communication to endpoints located in different AWS Regions through the use of Inter-Region VPC Peering.

I recommend reading this AWS blog, which outlines an architecture involving PrivateLink and Transit Gateway. This approach has the potential to significantly decrease the number of VPC endpoints, streamline the deployment of VPC endpoints, and offer cost optimization benefits, especially when implementing solutions at scale.

Scaling considerations

While it’s possible to configure many-to-one connectivity using AWS PrivateLink, there are several important factors to keep in mind when considering this type of scaling:

  • Cost and management: As you introduce new consumer VPCs to AWS PrivateLink, you’ll also be adding new VPC endpoints to your infrastructure, which can add to your billing and infrastructure management overhead.
  • AWS PrivateLink quotas: Be sure to take into account AWS PrivateLink quotas, as these define the limits for various aspects of your PrivateLink setup.
  • Network throughput: VPC endpoints support a maximum throughput of 100Gbps. This is an important consideration for applications that have high network demands when exposed through AWS PrivateLink.
  • LB quotas: Be considerate about network load balancer quotas/gateway load balancer quotas.
  • IP requirements: AWS PrivateLink consumes a certain number of IP addresses for Load Balancers and endpoints from your VPC’s IP address pool. Ensure that your VPCs can accommodate these IP requirements without causing IP address exhaustion.

Transit Gateway as an alternative?

Let’s look at Transit Gateway if it can be an alternative in a continually expanding VPC environment.

  • If unidirectional traffic is your primary requirement, AWS PrivateLink is the choice.
  • For a cost-efficient solution, AWS PrivateLink is certainly more economical than Transit Gateway.
  • It’s worth noting that Transit Gateway is not suitable when dealing with VPCs that have overlapping CIDRs.
  • In a nutshell, Transit Gateway becomes a viable alternative only when you are designing a highly scalable solution involving a significantly huge number of participating VPCs with non-overlapping CIDRs, and your solution prioritizes simplicity and reduced management overhead over cost considerations.

VPC Peering vs AWS PrivateLink vs Transit Gateway

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In this article, we will compare three different ways to cross-VPC communication: VPC peering, AWS PrivateLink, and Transit Gateway. We’ll also discuss when to use each one and help you choose the best option. It’s important to note that we won’t dive deep into each implementation; instead, we’ll focus on their advantages, limitations, and ideal usage scenarios.

Peering or PrivateLink or Transit Gateway!

When operating Cloud Native applications, maintaining private and secure communication between applications is crucial. These applications may be distributed across various VPCs, whether within the same account or across different accounts. In such scenarios, we establish cross-VPC communication through the use of VPC peering, AWS PrivateLink, or Transit Gateway.

Let’s look at them one by one.

VPC Peering

It is a networking connection between two VPCs where network traffic can be routed across two VPCs. Read more about VPC peering here. Let’s look at the pros and cons of the VPC peering –

Advantages

  • Relatively straightforward to configure. It’s an invite-accept configuration.
  • Create network connectivity between two VPCs, resulting in a scalable network connection solution, enabling all resources in one VPC to communicate with resources in the other.
  • A simple, secure, and budget-friendly option.
  • VPC Peering comes at no additional cost; you are only billed for data transfer costs. The data transfer cost for VPC peering within the same Availability Zone (AZ) is completely free.

Limitations

  • Peering VPCs with overlapping CIDRs is not possible.
  • Peering is non-transitive.

Ideal usage

  • Individual VPC-to-VPC connections.
  • A situation that demands full network connectivity with other VPC.
  • A use case where a simple and cost-effective solution is expected.
  • This approach is not well-suited for handling a large number of VPCs. In such cases, Transit Gateway is the preferred solution. Since mesh networking between a large number of VPCs using peering adds complexity to the architecture.

AWS PrivateLink

It’s an AWS service that enables you to access AWS services over a private network connection, rather than over the public internet. Read more about AWS PrivateLink here.

Advantages

  • A selective sharing of services between VPCs. Unlike VPC peering, where all VPC network access is unrestricted, AWS PrivateLink permits only specific services to be accessible across VPC.
  • This is a secure solution for private connectivity of services across VPCs or on-premises.

Limitation

  • It’s a connectivity option between your VPC and AWS services, not between VPCs. For VPC-to-VPC connectivity, consider VPC peering or Transit Gateway.
  • The setup process is complex.
  • It necessitates the creation of Network Load Balancers (NLB), Application Load Balancers (ALB), and Gateway endpoints, which introduces additional costs and management overhead.
  • Enabling PrivateLink for existing services requires design adjustments, including the incorporation of the above components into the current architecture.

Ideal usage

  • It can be valuable in hybrid cloud configurations to make services accessible privately between VPCs and on-premises environments.
  • It’s beneficial for accessing AWS’s public services like Amazon DynamoDB and Amazon S3 through AWS’s backbone network, ensuring secure, fast, and reliable connectivity while potentially reducing network costs.
  • It’s applicable for creating isolation by selectively exposing specific services to particular VPCs.

Transit Gateway

AWS Transit Gateway is a service that makes network routing easier for your Amazon Virtual Private Clouds (VPCs), on-premises networks, and VPN connections. It helps to simplify and centralize network routing. Read more about Transit Gateway here.

Advantages

  • A concrete method to link numerous VPCs, network devices, VPN connections, or an AWS Direct Connect gateway, featuring transitive routing for the simplification of network design.
  • Multicast support facilitates effortless distribution of content and data to various endpoints.
  • Efficiently manage and control large-scale networking via a single, unified service.

Limitations

Ideal usage

  • It is well-suited for hub-and-spoke architectures, designs that involve a significant number of VPCs, transitive routing needs, and global or multi-region network designs.
  • It is designed for scalability and is particularly suitable for continuously expanding environments.
  • It’s valuable for efficiently managing network connectivity among a large number of diverse participants.

Which one should I use?

As we’ve discussed, each of these three networking approaches has its specific areas of focus tailored to particular use cases. Consequently, the choice depends entirely on your unique requirements.

VPC Peering is an excellent choice when you need to connect a limited number of VPCs with minimal cost implications and management overhead.

AWS PrivateLink is the right option when you intend to selectively expose services to other VPCs, although it involves additional costs, extra networking components, and the associated management overhead.

Transit Gateway can serve as an alternative to VPC Peering as you scale to a larger number of VPCs, simplifying network management at the expense of some additional costs. It’s also well-suited for connecting various network entities with anticipated scalability.