Nutanix Flow: Smarter L4 Load Balancing

Introduction

As applications become increasingly distributed and cloud-native, efficient traffic management within virtualized environments has become critical. Nutanix Flow Virtual Networking (FVN) delivers an advanced, software-defined approach to networking and security and at the heart of this system lies the Network Load Balancer (NLB). It works cohesively with a suite of Nutanix products not limited to:

• The NLB ensures that traffic is intelligently distributed across virtual machines (VMs) or services, improving performance, scalability, and availability for modern workloads like Nutanix Kubernetes Platform (NKP).
• Self-healing, auto-scaling, load-balanced apps with no manual network configuration for multi-tier application deployment with Nutanix Self-service.
• Single, native load-balancing layer for all AHV workloads-simple, scalable and consistent across hybrid deployments with Nutanix NCI.
• Providing VIP-based access for auxiliary service nodes (scanning, proxies) when used with Nutanix Files and Objects.

This integration helps IT teams efficiently distribute traffic across workloads, ensuring high availability, simplified operations, and improved application responsiveness all without external appliances or complex configurations.

What is the Nutanix Flow Network Load Balancer?

A load balancer is a device that acts as a reverse proxy and distributes network or application traffic across a number of servers. Load balancers are used to increase capacity (concurrent users), improve reliability of applications and add site fault tolerance. They improve the overall performance of applications by decreasing the burden on servers associated with managing and maintaining application and network sessions, as well as by performing application-specific tasks.

Load balancers are generally grouped into two categories: Layer 4 and Layer 7. 

• Layer 4 load balancers act upon data found in network and transport layer protocols (IP, TCP, FTP, UDP).
• Layer 7 load balancers distribute requests based upon data found in application layer protocols such as HTTP.

Note- Nutanix offers L7 Load Balancing via 3rd Party vendors like Traefik, F5.

The Network Load Balancer (NLB) in Nutanix Flow is a Layer 4 (Transport Layer) load balancer designed to handle large volumes of TCP and UDP traffic with high performance and low latency. It’s tightly integrated into the Nutanix AHV hypervisor and Flow Virtual Networking, enabling seamless deployment and management without relying on external hardware or third-party appliances.

What are the key capabilities of the Nutanix Flow Network Load Balancer?

• Layer 4 Load Balancing-The NLB operates at Layer 4, distributing traffic based on IP address and port. This provides fast, efficient load distribution for protocols like HTTP(S), database connections, and custom application traffic.
• High Availability and Scalability-By automatically balancing requests across multiple backend servers or services, the NLB eliminates single points of failure and supports horizontal scaling of applications.
• Integrated Security and Policy Management-Through Nutanix Flow’s microsegmentation and policy-based controls, NLB traffic can be tightly managed ensuring that only authorized flows reach backend services.
• Native Integration with Flow Virtual Networking-Because it’s built into the same control plane as Flow Virtual Networking, administrators can define, deploy, and monitor load-balanced services directly within the Nutanix Prism Central interface.
• Health Monitoring-The NLB continuously checks the health of backend endpoints and automatically removes unhealthy nodes from the pool, ensuring uninterrupted service delivery.

What are some of the key benefits of Nutanix Flow Network Load Balancer?

With the Nutanix Flow Network Load Balancer, you can achieve the following efficiencies:

• Eliminates dependence on external hardware or third-party software.
• Distribute the network traffic load across multiple guest VMs efficiently, by allowing you to add and remove load balancers and their members based on demand for more efficient distribution of network load.
• Distribute the requests only to active VMs for better high availability and reliability.
• Monitor the health of target VMs to mark active and inactive targets.
• Centralizes visibility and management in Prism Central.
• Strengthens network resilience in virtual and hybrid environments.

The Network Load Balancer is a distributed load balancer that is implemented in the AHV host to distribute traffic across the network. Network Load Balancers improve the capacity, reliability, and overall fault tolerance of the network and applications using the network. The Network Load Balancer feature implements high availability for network and applications and improves the performance of the network and applications. Two key use-cases that you can solve out of the box:

External Load Balancing

This load balancing involves the distribution of traffic flowing into the VPC from sources external to the VPC.

Internal Load Balancing

This load balancing involves distributing the traffic flowing within the VPC, in other words, intra-VPC traffic, among a set of VMs in the VPC. For such load balancing, the virtual IP address assigned to the load balancer need not be reachable from outside the VPC.

How can you deploy the Nutanix Flow Network Load Balancer?

The Network Load Balancer can be deployed very easily from the Prism Central UI and the same can be achieved in a few quick steps. 

• Let’s quickly take a look at one such Network Load Balancer that we have created.
• As you can see, the VIP IP is an external subnet with an IP range of 192.168.1.x and we have assigned a Floating IP x.x.x.x which is routable and available over the intranet/internet.

• We have already created some backend instances and then can be selected as the targets easily.

• The Network Load Balancer monitors the health of target VM NICs for both TCP and UDP protocols. These are configurable too.

• You can reach the VIP of the Network Load Balancer over the private IP as well as the Floating IP.
  • Notice on the right side where the three backend servers are responding equally to traffic that is being sent to them.

• You can also view the health of the backends and should there be a change in the health of the backends (with the respective backend going down or health probes being missed).

Conclusion

The Network Load Balancer in Nutanix Flow Virtual Networking offers a powerful, integrated solution for distributing network traffic efficiently within virtualized and hybrid cloud environments. By combining high-performance Layer 4 load balancing with Nutanix’s intuitive management and security capabilities, it empowers IT teams to build scalable, resilient, and secure application infrastructures all within the Nutanix ecosystem.

Stay tuned for part-2 of this blog series where we will talk about a very interesting feature called Load Balancer Categories.

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