What I Learned Running Cost Monitoring for 50+ Kubernetes Clusters

Across dozens of clusters, the patterns repeat.

• Wins: enforce labels day one; block no-limit pods; move 50% stateless to spot; trim log retention.
• Fails: trusting billing data alone; ignoring egress; letting staging sprawl.
• Habits: weekly waste report, monthly egress review, quarterly node mix rebalance.
• Culture: celebrate cost saves like performance wins; add “cost regression?” to postmortems.
• Playbook:
  • Week 1: label audit + admission; enable quotas/limits.
  • Week 2: move top 5 stateless workloads to spot with buffer.
  • Week 3: trim log/metrics retention; prune idle LBs/PVCs.
  • Week 4: tune HPA caps and right-size top wasteful services.
• Pitfalls: untracked cross-AZ traffic, temporary quota bumps that never expire, and price sheets that drift from actual rates.

Apply these and most clusters drop 20–40% spend within a quarter.***