Separate Prism Central Control Plane

Nutanix Prism Element initially served as a straightforward and user-friendly tool for managing a single HCI cluster.

As time passed, Prism Central transformed into a comprehensive control plane capable of handling multi-cluster management, automation, security, governance, and cloud services.

This evolution added robust features; however, it also led to a management footprint that is no longer suitable for production clusters in large enterprises.

This post discusses why mandating Prism Central on production Nutanix clusters is both a poor strategic and technical choice, and why enterprises should advocate for a separate management cluster for Prism Central.

From Lightweight and strong Element To Heavyweight flawed Central

Every Nutanix cluster ships with Prism Element, the embedded management interface that configures, manages, and monitors only that one single cluster.

For years, Prism Element was enough for most customers: it handled VM lifecycle, storage, networking, and day‑to‑day operations with minimal overhead directly on the platform.

Prism Central (PC), in contrast, is a separate VM (or VM set) that provides a global, multi‑cluster management plane, advanced analytics, automation, and integration with higher‑level Nutanix services.

Nutanix has increasingly tied advanced features (Prism Pro/intelligent operations, cost governance, self‑service, Flow security, DR orchestration) to Prism Central instead of Prism Element. Strategically, that nudges customers toward “PC everywhere”—often deployed directly on the same clusters it manages.

Naturally, this increases their subscription revenue since they charge for activating these features.

However, what occurs when too many features are activated? Can Prism Central handle and manage it effectively? This is why this post advises that you approach this situation with caution and consideration.

On paper, the default PC scheme simplifies the story. In practice, it centralizes a heavy, chatty, evolving control plane right on top of business‑critical workloads.

The Hidden Overhead Of Prism Central On Production Clusters

For a small lab or a single SMB cluster, running Prism Central on‑cluster is tolerable. At enterprise scale, its overhead becomes a structural problem.

1. Significant compute and memory tax

A “small” Prism Central VM typically requires around 4 vCPUs, 18 GB RAM, and 100 GiB of storage; larger, scaled‑out deployments can jump to 6 vCPUs, 28 GB RAM and 500 GiB or more.

Real‑world users however regularly allocate well into double‑digit vCPU counts for Prism Central plus additional cores for CVMs and adjacent Nutanix services (Files, Flow, analytics).

I myself worked at Nutanix for five years and I found I needed to use AMD EPYC CPU with a ton of cores to pull this off in a reasonably managed way.

Most Nutanix SE's design their clusters without taking the management overhead into account properly or the constant cluster update antics which requires an extra Node on it's own to accommodate the workload transfer when it executes said AOS updates.

Anytime you see a Nutanix cluster with just three nodes with high workloads you are looking at big upgrade trouble.

You cannot take a 3 node Nutanix cluster seriously, this is a lab rat or bored IT folk plaything.

I often found myself needing 20 cores and 512GB of RAM just for PC. Even then I could get it to fail and fall over pretty easily.

One practitioner I worked with at an online payment system in San Jose, CA with a 4‑node cluster (64 physical cores) described this scenario: 18 vCPUs just for Prism Central, 32 more across CVMs, plus extra vCPUs for Nutanix Files and file analytics - over 70 virtual cores reserved for management on a 64‑core cluster, leaving limited headroom for actual application VMs.

It did not take me long to convince him he needed AMD EPYC CPU with a ton of cores and extra RAM for him to become a Nutanix fan.

At scale, that management overhead tax directly competes with production workloads and inflates hardware sizing simply to feed the control plane!

The Python coding they use and the databases running in the background can swiftly bring PC to it's knees.

Python is also not the way to design this management leviathan.

2. Noisy‑neighbor effects on critical workloads

Prism Central does heavy lifting: inventory collection, metrics ingestion, anomaly detection, capacity analytics, policy evaluation, DR orchestration, and more.

Those tasks aren’t constant, and their peaks rarely align with business usage, which means they can (and will) spike CPU, memory, and I/O at inconvenient times.

When PC shares nodes with critical workloads, bursts in:

• Telemetry and time‑series metrics processing

  
  

• Machine‑learning‑driven right‑sizing and anomaly detection

  
  

• DR and replication workflows

can show up as jitter, increased latency, or noisy‑neighbor contention on the same hosts that run business applications. On a lightly loaded test cluster, that might be fine; on a busy enterprise cluster? That is totally unacceptable.

3. A single control plane that expands the blast radius

By design, Prism Central is a global control plane for multiple clusters. That’s its biggest benefit - and paradoxically its biggest risk.

If Prism Central lives on a production cluster and that cluster experiences:

• Node failures or severe performance degradation

  
  

• Storage issues impacting management VMs

  
  

• Hypervisor problems or misconfiguration

you don’t just lose workloads on that cluster; you also degrade or lose the management layer for other clusters it manages.

Multiple users have highlighted the operational risk of hosting PC on the same infrastructure that is supposed to be orchestrated or recovered during a disaster.

In other words: the platform tasked with coordinating DR, policy enforcement, and global operations is itself vulnerable to the same events that it’s meant to orchestrate.

4. Lifecycle friction and upgrade coupling

Prism Central has its own release cadence, feature roadmap, and dependency matrix. New capabilities often require:

• Updated Prism Central versions

  
  

• Additional memory/CPU allocations

  
  

• Changes in underlying cluster versions or drivers

When PC is co‑located with production, every “simple” control plane upgrade now sits on the critical path for application SLAs and change management windows.

The blast radius for regressions or misconfiguration increases, and rollback paths get messier because your management plane shares the exact same resources and maintenance activities as your workloads.

A separate management cluster isolates that risk into a small, purpose‑built footprint.

Why A Separate Management Cluster Is The Enterprise Pattern

Most mature enterprise environments already separate control and data planes: think dedicated management vCenter, out‑of‑band storage controllers, or separate monitoring and logging infrastructure. The same discipline applies cleanly to Nutanix.

1. Predictable, ring‑fenced resource consumption

Running Prism Central on a dedicated management cluster (or on paired management clusters per site) ring‑fences its CPU, memory, and storage usage away from production. You size a small set of nodes specifically for:

• Prism Central (and its scale‑out needs)

  
  

• Supporting infrastructure like AD connectors, monitoring, backup proxies, etc.

This keeps production clusters focused on application workloads while the management cluster absorbs the variable load of analytics, reporting, and orchestration.

2. Reduced blast radius and better DR design

Community best practices increasingly recommend independent Prism Central instances per availability zone or major site, explicitly to avoid losing central management when a cluster goes down. Enterprises often deploy:

• Prism Central‑A on Site A’s management cluster, managing Site A clusters and protecting Site B

  
  

• Prism Central‑B on Site B’s management cluster, managing Site B clusters and protecting Site A

If a production cluster or entire site fails, the peer site’s Prism Central remains online to orchestrate VM recovery, policy application, and failover workflows.

Nutanix itself promotes the use of Nutanix Central and multi‑cluster Prism Central designs for large environments, which aligns with this decoupled control‑plane model.

3. Cleaner security and access segmentation

A standalone management cluster makes it easier to:

• Enforce stricter network segmentation and zero‑trust controls around the control plane

  
  

• Apply distinct RBAC and identity policies for “who can touch the management fabric” versus “who can access workloads”

  
  

• Audit and monitor control‑plane activity separately from tenant/application operations

Prism Central already supports global policies and role‑based access across clusters.

Hosting PC on a dedicated management cluster simply brings the underlying infrastructure model in line with those security goals.

4. Independent lifecycle, capacity, and roadmap alignment

Finally, a separate cluster lets you treat Prism Central as an independently managed product:

• Upgrade PC on its own schedule, with its own rollback and test plans

  
  

• Scale the management cluster as you add clusters, sites, or new PC features, without resizing production clusters

  
  

• Decommission or migrate PC instances without impacting application capacity planning

This aligns with how experienced Nutanix SEs and SAs present Prism Central for large, distributed environments: as a centralized, multi-cluster control plane, rather than just another VM on a random production host.

What needs to happen here is customers pressing Nutanix to re-architect and rebuild Prism Central the right way (with proper code) and to also offer lighter cluster use in just Prism Element if the customer so desires.

It's a cost thing and there is no one size fits all with this one...and yes it is a very big deal!