Cloud Identity and Access: Google Cloud, AWS, Azure

Authentication proves who a user or workload is; authorization determines what that identity may do. Successful sign-in does not grant access to every resource. User sessions, service identities, API tokens and device certificates have different lifecycles. Design session duration, token renewal, employee departure, lost-device handling and emergency access alongside initial sign-in. Measure which existing sessions remain usable and which new accesses are denied when the identity provider becomes unavailable.

Least privilege limits the permissions needed for a task to specific resources and time periods. Giving everyone the same administrator role complicates access reviews and investigations. Separate daily-use identities from privileged accounts, and restrict interactive use and unnecessary network access for service identities. An access matrix should show which operation an identity may perform on each resource. Test whether an application keeps working after a permission is removed: unnecessary privileges sometimes become visible only during controlled reduction.

A trust boundary separates components governed by different access decisions; a failure domain groups resources that one event can affect together. Two VLANs do not create a strong trust boundary when routing between them is unrestricted. Backups in different folders still share a failure domain if one administrator can delete both. Assess physical location, identity provider, management account, network path and power source separately. Test which access paths and recovery options remain available when a component is lost.

A policy needs management as its scope changes, not just when it is enabled. Separate drafting, observation, pilot deployment, enforcement and periodic review. Every exception needs an owner, reason, scope and expiry date. A successful pilot can still cause production false positives if test data does not represent real user behaviour. Identify affected users and applications before deploying with measurable acceptance criteria. A rollback path should identify who may reverse the change and under which conditions, rather than merely locating an interface button.

Telemetry combines logs, metrics and events that explain system behaviour. A log describes an event, a metric shows behaviour over time, and a distributed trace follows a request across components. Clock differences can make one event appear to occur at several times. Use synchronized clocks, reliable source identifiers and consistent time-zone handling. Alarm design should consider duration and user impact alongside thresholds. Monitor gaps in collection separately: absence of logs must not be interpreted as absence of incidents.

Installability does not prove production support. Review the compatibility chain across OS, application, drivers, extensions and management tools. Update plans should record version, support end, restart needs and rollback methods. An unrepresentative test environment can produce misleading results. Validate service health and existing workflows after a change, not just version numbers. Remember that pinning a version can also prevent future security fixes.