Idle EC2 Instances

Why This Matters

Idle EC2 instances consume full compute resources and billing while providing minimal actual workload. Unlike oversized instances that still serve purpose, idle instances below 5% CPU likely serve no meaningful function and represent pure waste.

Common causes:

• Over-provisioned development environments
• Forgotten test instances
• Applications that no longer receive traffic but weren't properly decommissioned

How to Identify Idle EC2 Instances

AWS Saver flags EC2 instances as idle when they meet these criteria:

1. CPU utilization under 5% averaged over 24 hours
2. Running state (not stopped or terminated)
3. Aged over 7 days (avoids flagging new deployments)
4. Monthly cost above $5 (focuses on meaningful savings)

How to Fix Idle EC2 Instances

Step 1: Find all running instances

aws ec2 describe-instances \
  --filters Name=instance-state-name,Values=running \
  --query 'Reservations[].Instances[?State.Name==`running`].[InstanceId,InstanceType,Tags[?Key==`Name`].Value|[0]]'

Step 2: Get CPU utilization over 24 hours

aws cloudwatch get-metric-statistics \
  --namespace AWS/EC2 \
  --metric-name CPUUtilization \
  --dimensions Name=InstanceId,Value=i-1234567890abcdef0 \
  --statistics Average \
  --start-time $(date -u -d '1 day ago' +%Y-%m-%dT%H:%M:%SZ) \
  --end-time $(date -u +%Y-%m-%dT%H:%M:%SZ) \
  --period 3600

Automation Available

Skip the manual work. AwsSaver automatically detects and prioritizes this issue across your entire AWS infrastructure.

✅ Automated detection - Scans running instances for idle usage patterns ✅ Cost impact analysis - Shows exact monthly waste per idle instance
✅ Conservative filtering - Only flags instances aged over 7 days and above $5/month cost