Fargate Resource Rounding and Per-Pod Overhead Driving Step-Up Costs

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Tai Nguyen

CER:

AWS-Compute-9349

Service Category

Compute

Cloud Provider

AWS

Service Name

AWS EKS

Inefficiency Type

Suboptimal resource sizing

Explanation

This inefficiency occurs when pod resource requests—often inflated by sidecar containers—push total memory or CPU just over a Fargate sizing boundary. Because Fargate adds mandatory system overhead and only supports fixed resource combinations, small incremental increases can force a pod into a much larger billing tier. This results in materially higher cost for marginal additional resource needs, especially in workloads that run continuously or at scale.

Relevant Billing Model

Fargate charges per vCPU-second and GB-second based on the provisioned pod size. EKS on Fargate adds a fixed 256 MB memory overhead per pod and rounds resource requests up to the nearest supported compute configuration.

Detection

Review pods whose requested resources sit near known Fargate sizing thresholds
Assess whether sidecar containers materially increase total requested CPU or memory
Identify workloads where provisioned capacity significantly exceeds observed workload needs

Remediation

Right-size pod resource requests with explicit awareness of Fargate overhead and rounding behavior
Tune or consolidate sidecar resource requests to avoid unnecessary tier step-ups
Consider managed node groups for workloads where bin-packing efficiency outweighs Fargate simplicity

Relevant Documentation

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