WHAT YOU WILL LEARN
Learning objectives
- Explain trust boundaries
- Compare redundancy and backup
- Recognize dependency and segmentation needs
Make trust boundaries explicit
A trust boundary separates contexts with different access assumptions. Applications, networks, cloud tenants and administrative interfaces all have boundaries. Use authentication, authorisation and validation at those boundaries instead of assuming that a request from inside the organisation is safe.
Design for failure
Redundancy can keep a service available when a component fails; backups help recover data or state. Neither automatically substitutes for the other. Identify common dependencies and test failure conditions. Two replicas controlled by the same compromised administrator may share the same failure mode.
APPLIED EXAMPLE
Put it in context
A fictional service has two web servers but both depend on one database and one identity service. Its architecture review considers those shared dependencies before claiming end-to-end resilience.
Illustrative scenario for learning, not a claim about a verified customer incident.Common mistakes
- Confusing replication with recoverable backup
- Ignoring shared dependencies
- Relying on network location as identity
Your practical checklist
Checklist ticks are temporary and are not recorded as account progress.
MINI RECAP
Good architecture makes access assumptions and failure modes visible.