OpenShift Pod Density Calculator

Compare the 110 default and 250 maximum pods per node against the 4-pods-per-vCPU guideline and your DaemonSet overhead.

About OpenShift Pod Density Calculator

Two independent ceilings apply. maxPods is a hard kubelet limit driven by network and runtime scalability, while the pods-per-vCPU guideline reflects the fact that each pod costs the kubelet and the runtime real CPU regardless of what the container does. DaemonSets then take their slots off the top of whichever ceiling is lower. Density decides node size and therefore cost, and a cluster running above 90% of its pod capacity cannot survive a node failure — the evicted pods have nowhere to reschedule.

Formula

OpenShift Pod Density

application pods per node = min(maxPods, vCPUs × pods per vCPU) − DaemonSet pods; cluster capacity is that multiplied by the node count.

maxPods: Kubelet ceiling — 250 on OpenShift, 110 upstream, 500 only with tuning
pods per vCPU: Practical scheduling guide of about 4 pods per vCPU
DaemonSet pods: Per-node agents that consume slots before any application pod

Worked example

With the default values below, OpenShift Pod Density Calculator returns Application Pods per Node of 56. Change any input above and every figure here is recalculated in your browser.

Inputs used

Worker nodesaccepts 1–2,000 nodes: 8 nodes
vCPUs per nodeaccepts 1–512 vCPU: 16 vCPU
Pods per vCPU guidelineaccepts 1–20 pods: 4 pods
maxPods in the kubelet configaccepts 10–500 pods: 250 pods
DaemonSet pods per nodeaccepts 0–60 pods: 8 pods
Application pods running todayaccepts 0–200,000 pods: 620 pods

Results

Application Pods per Node: 56 pods
Cluster Pod Capacity: 448 pods
Ceiling from the vCPU Guideline: 64 pods
Pod Capacity Used: 138.4%
Pod Headroom Remaining: 0 pods
Density Verdict: Nearly full — a single node loss would leave pods unschedulable

Step by step

1Values used
2OpenShift Pod Density
3Application Pods per Node= 56 pods
4Cluster Pod Capacity= 448 pods
5Ceiling from the vCPU Guideline= 64 pods
6Pod Capacity Used= 138.4
7Pod Headroom Remaining= 0 pods
8Density Verdict= Nearly full — a single node loss would leave pods unschedulable

Assumptions and limits

The result is derived only from the 6 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax or compounding frequency into account.
Figures are rounded for display to 1 decimal place, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is OpenShift Pod Density calculated?

application pods per node = min(maxPods, vCPUs × pods per vCPU) − DaemonSet pods; cluster capacity is that multiplied by the node count. Two independent ceilings apply. maxPods is a hard kubelet limit driven by network and runtime scalability, while the pods-per-vCPU guideline reflects the fact that each pod costs the kubelet and the runtime real CPU regardless of what the container does. DaemonSets then take their slots off the top of whichever ceiling is lower.

Why does OpenShift Pod Density matter?

Density decides node size and therefore cost, and a cluster running above 90% of its pod capacity cannot survive a node failure — the evicted pods have nowhere to reschedule.

What values do I need to enter?

This calculator takes 6 inputs: Worker nodes, vCPUs per node, Pods per vCPU guideline, maxPods in the kubelet config, DaemonSet pods per node, Application pods running today. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

Why is 250 the supported ceiling rather than 500?

Beyond about 250 pods the kubelet's status reporting, the CNI's IP address management and the iptables or nftables rule set all grow to the point where node status updates and service reconvergence become the bottleneck. 500 is achievable but requires deliberate tuning and testing.