LightSwitchOps

What?

• Term coined by Holly Cummins
• Making turning servers off as safe and easy as turning lights off.
• turning it off and on again must
  • be fast
  • actually work
    • idempotency
    • resiliency
• → "when we scripted turning them off at night, we reduced our cloud bill by 30%"

Sources:

• https://www.redhat.com/en/resources/greener-java-applications-detail
• https://hollycummins.com/cloud-zombies-qcon-london/

Dedicated vs. shared hardware

if you have dedicated hardware in a data centre and you switch it off during night and weekends, it will use less energy but it will significantly impair lifespan of the hardware due to bending of the material (warm-cold-warm cycles). It will last months instead of years! My takeaway is that you should avoid using dedicated hardware if you use the 'light-switch OPS' approach, instead, use shared hardware.

— Evert-Jan de Bruin

How?

• write scripts
• implement GitOps workflows (helps to gain confidence)
• using Kubernetes? use kube-green or DailyClean
• improve startup time of your applications