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Core InfraWorkload RightsizingBoot-Time Optimization

Boot-Time Optimization
Available in v1.30.14+

Some workloads consume significantly more CPU during container startup than during steady-state operation. Without accounting for this, a right-sized workload may experience CPU pressure at boot — causing slow starts, failed readiness probes, or stress on the node it lands on.

Boot-time optimization solves this by detecting the startup spike pattern and making three targeted adjustments: it shapes the CPU request during the boot window, intervenes immediately when a starting pod is under CPU stress, and guides Karpenter to schedule pods on nodes large enough to absorb the spike.

What It Does

When ScaleOps detects that a workload’s CPU usage during startup is significantly higher than its steady-state usage, it makes the following adjustments:

Startup-aware CPU requests CPU requests during the boot window reflect the higher startup demand rather than the steady-state recommendation. Once the boot window closes, the request is reduced back to the steady-state recommendation. This flow works alongside in-place optimization.

Immediate intervention on startup CPU stress If a pod experiences CPU pressure while booting, ScaleOps reacts immediately using the boot-time CPU recommendation — independent of the normal optimization cycle.

Karpenter node affinity guidance On Karpenter-managed clusters, ScaleOps adds a preferred node affinity to pods so they are scheduled on instance types large enough to handle the startup spike. This reduces the chance of a pod landing on a node that is correctly sized for steady state but under-provisioned for boot.

Boot-time optimization applies to CPU only and covers all workload types.

How to Enable

Built-in policies

Boot-time optimization is enabled by default in all built-in policies. No action is required.

Custom policies

Enable or disable the setting in the policy editor:

Policy edit → Automation → Boot-time optimization

GitOps / Policy CR

spec: policyOptimize: rightSizePolicy: bootTimeOptimizationEnabled: true # or false to disable

Limitations

  • CPU only — Memory startup spikes are not acted on.
  • Karpenter node affinity — The preferred node affinity is added only for workloads running on Karpenter-managed nodes. It has no effect on other node provisioners.