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Tackling Kubernetes IP Exhaustion and Overlap

In Kubernetes environments, IP exhaustion and overlap are common challenges. Learn how Aviatrix's Kubernetes Firewall provides a solution.

Tim McConnaughy srcset=
Updated April 8, 2025 in multicloud, Kubernetes By Tim McConnaughy

Kubernetes is a great example of how a solution’s greatest strength can be its worst enemy. This open-source container orchestration platform automates the deployment, scaling, and management of containerized applications, removing significant headaches from enterprise developers and platform engineers. Kubernetes allows enterprises to scale up and down quickly across multiple cloud platforms, optimize performance, ensure resiliency, and use automation to remove tedious and error-prone manual processes. Flexibility; portability; security; ease-of-use – Kubernetes seems to solve every major deployment issue.

Unfortunately, the rapidly-changing and temporary nature of Kubernetes clusters, the very thing that makes this solution powerful, means that these clusters eat up IP addresses like a plague of locusts. As Anirban Sengupta, Aviatrix’s Chief Technology Officer and Senior Vice President of Engineering, says, “Kubernetes is IP-hungry.” Eventually, enterprises tend to run out of IP addresses to use, leading to configuration and operations problems.

Here’s an overview of the challenge of IP exhaustion and overlap in Kubernetes environments and some tips to overcome them.

 

My IPs are Exhausted: The Scope of the Issue

The scalability and portability of Kubernetes clusters may make developers feel that the possibilities are limitless – until they run out of IP addresses for clusters.

A DevOps or Platform Engineer who is happily deploying multiple clusters across multiple environments will face:

  • An IP famine – The rapid creation and termination of pods can quickly deplete the available IP address space.
  • IP conflicts and performance issues – The issue will cascade if you don’t address it, preventing you from deploying and introducing latency. Teams and applications who are trying to work in the same cluster across large-scale, multi-tenant environments will really struggle.
  • Overlapping CIDR blocks – If you try to reuse IP addresses across cloud platforms, you may duplicate, leading to more confusion and operational complexities.
  • Loss of connectivity and compliance risks – Overlapping CIDRs can cause you to lose connectivity in your environment, as well as risking security and compliance.

 

This is the kind of problem that only gets worse. You need an effective, long-term solution to make sure your environment is secure and scalable – without wasting your Operation teams’ time and resources.

Example of IP overlap: 

Diagram illustrates IP overlap in a multicloud environment. In the AWS cloud, two regions both have 10.1.2.0/24 and 10.1.3.0/24 in different regions.

Kubernetes clusters often reuse IP addresses. In this example, 10.1.2.0/24 and 10.1.3.0/24 are duplicated in separate AWS Availability Zones. These duplications complicate communication between clusters as well as communication with outside resources.

 

Complex Workarounds: The Solutions That Don’t Completely Solve the Problem

To prevent their environments from going under, many networking teams use a few workarounds:

  • Transitioning to IPv6 – If you’re running out of IPv4 addresses, you can transition to IPv6 to expand the number of addresses you can use. However, this transition is as difficult and expensive as it would be for a country to switch currencies or go from the Imperial to the Metric system of measurement. It would involve supporting new and legacy systems at the same time and trying to maintain business operations while you switch over, another complicated task.
  • NAT Gateway solutions – Another workaround is using NAT gateways to translate overlapping IP addresses into a different IP address to avoid a conflict. Again, this works, but it means deploying many private one-way NAT Gateways across a vast network. Managing these deployments this is a huge task for Cloud Operations teams.
  • Cloud service provider solutions – You can use a cloud-native solution like AWS’s Private Link to solve the issue of IP overlap in one cloud. The downside is that you need to tailor individual solutions for every cloud platform you use – exactly the kind of time-consuming manual process that invites error and eats up overhead.
  • Kubernetes CNIs (Container Network Interface) – CNIs help manage the assignment of IP addresses in your Kubernetes environment. However, these solutions can’t solve multi-cluster IP conflicts or manage IP overlaps with the wider network efficiently.

 

Give Your IPs a Rest: Aviatrix’s Policy and Identity-Based Solution

Aviatrix’s newest feature, the Aviatrix Kubernetes Firewall, helps to resolve the issue of IP exhaustion and overlap for you, enabling your ability to use Kubernetes to rapidly scale, maximize performance, and operate within multiple cloud platforms with ease.

  • Advanced NAT Capabilities for IP Overlap Resolution – Our advanced NAT approach ensures uninterrupted Kubernetes-to-Kubernetes and Kubernetes-to-VM communication without IP conflicts. In other words, you can containerized apps and legacy systems with consistent segmentation and performance. NAT can sometimes be a nightmare to configure, but we make it simple. And because we are doing the NAT, our security policy and firewalling is NAT-aware too.
  • Consistent Connectivity – Instead of manually configuring IP addresses or NAT gateways across multiple clouds, use a consistent data plane that covers your entire single-, hybrid, or multicloud environment.

 

Don’t wait until you’re down to your last IP address to start planning. With the right solution, you can keep the ease and possibilities of Kubernetes without compromise.