Large infrastructure programs fail when reliability is treated as a property of individual devices rather than the system. Failure domains, change sequencing, and operational handoff criteria matter as much as redundancy on a diagram.
Design for operability
- Define failure domains explicitly — what fails together, and what must not.
- Stage changes so each step is reversible within the maintenance window.
- Align monitoring to expected behavior before declaring production readiness.
- Document who owns rollback decisions and escalation paths before cutover.
Reliability is a program property
Multi-site programs need consistent MOPs, acceptance criteria, and NOC handoff across regions. Without that discipline, each site becomes a one-off — and reliability becomes unpredictable as scale increases.