NCI 7.5 Deep Dive – Part Three: Flow CNI

Modern enterprise applications no longer run exclusively on virtual machines or Kubernetes. Most environments today operate a mix of both, and ensuring these workloads can communicate securely, scale consistently, and remain centrally managed is a growing challenge.

In Part Three of our NCI 7.5 deep-dive series, we focus on Flow Container Network Interface (Flow CNI). Flow CNI delivers unified networking for virtual machines and Kubernetes pods by extending Nutanix VPC constructs directly into Kubernetes clusters. This enables true hybrid application architectures where VMs and containers share the same networking and operational model.

Flow CNI is designed specifically for NKP-managed Kubernetes clusters, providing a Kubernetes-native way to eliminate networking silos and simplify hybrid operations on Nutanix.

What Is Flow CNI

Flow CNI is a Kubernetes networking plug-in that integrates Nutanix Flow virtual networking with Kubernetes clusters created and managed by Nutanix Kubernetes Platform (NKP). It uses overlay-based networking with Geneve encapsulation and native Kubernetes integration to allow:

• Kubernetes pods and virtual machines to coexist within the same VPC

• Consistent networking and security policies across compute types

• Centralized visibility and control through Prism Central

Important: Flow CNI is supported only for NKP-managed Kubernetes clusters.

Key Capabilities

Flow CNI delivers enterprise-grade networking features for Kubernetes environments, including:

• Overlay networking for pods using Geneve encapsulation

• Pod-to-service communication using cluster IP addresses and load balancing.

• east-west and north-south traffic within and across nodes

• External access using SNAT, egress IPs, and egress service

• Namespace-to-VPC mapping, enabling multiple VPCs within a single Kubernetes cluster

• Federation of VM and Kubernetes control planes across clusters

• Shared VPCs for hybrid VM and Kubernetes deployments which enable service discovery and access between VMs and Kubernetes services.

Deployment Models

Flow CNI supports two primary deployment patterns.

1)      Kubernetes-Only Environment

• A default VPC is created for Kubernetes pods

• No VM networking is associated with the VPC

2)      Federated VM and Kubernetes Environment

• Kubernetes clusters are associated with VPCs that already include VMs

• Pods and VMs communicate over the same VPC networks

Prerequisites at a Glance

Before deploying Flow CNI, ensure the following requirements are met:

• NKP-managed Kubernetes clusters only

• Required Nutanix software versions:

  • NKP 2.15 or later

  • AOS 7.5 or later

  • AHV 11.0 or later

  • Prism Central pc.7.5 or later

  • Network Controller 7.0.0 or later

• Flow deployed in Integrated with Prism Central mode (Flow Standalone mode is currently not supported)

• Helm installed and Flow CNI Helm package accessible

• Non-overlapping CIDRs for pods, services, and VPCs

• Kubernetes cluster onboarded to an XL Prism Central instance

Summary

Flow Container Network Interface bridges one of the most common gaps in enterprise platforms: consistent networking across VMs and Kubernetes. By extending VPC constructs into NKP-managed clusters, Flow CNI simplifies operations, enables hybrid architectures, and provides a strong foundation for application modernization on Nutanix.