Pod Security Standards (PSS) define three graduated security profiles — `privileged`, `baseline`, and `restricted` — that map clusters of securityContext settings to named enforcement levels, eliminating the need for teams to individually remember which security settings are required for production workloads. Pod Security Admission (PSA) is the built-in Kubernetes admission controller that enforces these profiles at the namespace level using three modes: `enforce` (reject non-compliant Pods), `audit` (allow non-compliant Pods but record violations in the audit log), and `warn` (allow but emit a warning in the API response). The `restricted` profile is the most stringent: it requires `runAsNonRoot: true`, `readOnlyRootFilesystem: true`, `allowPrivilegeEscalation: false`, `capabilities.drop: [ALL]`, and a non-privileged seccomp profile — exactly the security settings that the Deployment manifests from M3 already implement, meaning those manifests are `restricted`-compliant by construction rather than by accident.
25 minintermediate
Pod Security Standards and Pod Security Admission — enforcing container hardening
Analogy🏏Cricket
🏏 Think of it like cricket: The Pod-ReplicaSet-Deployment hierarchy maps precisely onto the three levels of IPL franchise team management. A Pod is a single player on the field at a given moment — the smallest unit of participation, carrying its own identity and fulfilling a specific role in the current game. A ReplicaSet is the franchise's match-day playing XI contract — it specifies that exactly eleven players matching a specific profile must always be on the field; if one is injured and leaves, the team management immediately sends a substitute of the same profile to restore the count. A Deployment is the franchise's season-long team strategy — it manages how the playing XI evolves between matches: when a new batting approach is adopted, the Deployment replaces the old XI with the new one in a controlled rolling substitution rather than swapping all eleven players simultaneously and disrupting team cohesion. Just as the franchise director does not manage individual players directly — the playing XI contract (ReplicaSet) handles the count and the season strategy (Deployment) handles the transitions — you never manage Pods directly in production; the Deployment manages the transition and the ReplicaSet maintains the count. This reveals why the three-level hierarchy exists rather than one omnibus 'workload' object: each level solves one specific problem, and composing three focused abstractions produces better separation of concerns than one object that conflates scheduling, scaling, and update management.
Lesson 23 of 33
0% complete