feat(curriculum): Phase 6C module upgrades, security assessment bank, ROOT 11 orientation
Upgrades six PARTIAL modules to the gold-module standard (lesson/demonstration/ knowledge-check/guided-exercise/lab(s)/reflection), preserving every existing lab activity_id and scenario_id: root-06-m03 (jobs/cronjobs/daemonsets), root-07-m04 (ingress/networkpolicy), root-07-m02 (configuration/secrets, converted in place from a bare 5-lab bank), root-09-m02 (serviceaccounts/rbac), root-09-m03 (network/supply-chain security), root-10-m03 (troubleshooting framework). root-05-m01 (20-task kubectl-fluency bank) gets a minimal bookending lesson + reflection rather than a full redesign, since each task already carries its own explanation. root-12-m01, root-capstone-m01, and root-09-m04 are promoted to READY via documented exceptions (no new activities) where adding one would misrepresent their intentional design. Wires a new rootnode-security-assessment (exam, 60min, hint_policy disabled) using the existing Phase 3B assessment engine: 3 required hands-on CORE scenarios + 4 random-draw pools covering SecurityContext, RBAC, network policy, and the 7 previously-unwired CKS MCQs. Wires the previously-unwired readiness-probe-task scenario as an OPTIONAL practice lab in root-10-m01, using the existing is_required model. Adds root-11-m01-devops-platform-thinking — an honest, lesson-only ROOT 11 orientation module naming DevOps/platform engineering practices already exercised in ROOT 05-10/12, explicit that GitOps/CI-CD/IaC/observability need lab infrastructure this platform doesn't yet provide. No fake labs. Adds infra/scripts/validate-course-content.js: cross-checks the DB against scenario/content files for duplicate ids, orphans, invalid references, cycles, sequence collisions, instructor-notes leakage, and (new) self-paced content deferring explanation to a live instructor. 0 errors against the resulting 22 courses/modules, 163 activities, 98 scenario files. No application code changed — every gap was satisfiable with existing tables (course_modules, module_activities, assessment_definitions) and the existing content-delivery pipeline. Co-Authored-By: Claude Sonnet 5 <[email protected]>
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Claude Sonnet 5
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# Demonstration: Tracing a Request Through Ingress
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## The setup
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An Ingress `web-ingress` routes `app.example.com/` to Service `web-svc`, which fronts a
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Deployment `web-app`. Nothing works yet from outside the cluster — let's see why, step by step.
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## Step 1: is the Ingress object even doing anything?
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```
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$ kubectl get ingress web-ingress
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NAME CLASS HOSTS ADDRESS PORTS AGE
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web-ingress traefik app.example.com 80 2m
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```
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`ADDRESS` is empty. On a real cluster, this column fills in once the Ingress controller has
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actually processed the object and assigned it a reachable address — an empty address after a
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couple of minutes is the first sign to check the controller itself, not your YAML.
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## Step 2: is the controller running at all?
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```
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$ kubectl get pods -n kube-system -l app.kubernetes.io/name=traefik
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NAME READY STATUS RESTARTS AGE
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traefik-7d8f9c6b5d-abcde 1/1 Running 0 10d
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```
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Running fine — so the ADDRESS delay in this case is transient, not a missing controller. (If
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this returned no Pods at all, THAT would be the actual root cause — no controller means no
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Ingress object ever gets acted on, exactly like the demonstration in ROOT 07's Ingress lesson
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described.)
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## Step 3: once ADDRESS populates, does the route actually work?
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```
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$ kubectl get ingress web-ingress
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NAME CLASS HOSTS ADDRESS PORTS AGE
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web-ingress traefik app.example.com 10.0.1.50 80 3m
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$ curl -H "Host: app.example.com" http://10.0.1.50/
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<html>...web-app's real response...</html>
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```
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Success — but notice the `-H "Host: app.example.com"` header. Ingress routes by HOSTNAME, not
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just by IP — hitting the Ingress controller's address WITHOUT the matching Host header would
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route differently (or not at all), because that's literally what the Ingress rule is matching
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on.
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## The general shape
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Symptom (nothing reachable from outside) has at least three DIFFERENT possible layers: the
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Ingress object itself, the controller processing it, and the Service/Pod chain underneath it
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(already covered in ROOT 07's Services module). Check them in that order — Ingress ADDRESS,
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then controller health, then the underlying Service — rather than guessing at DNS or firewall
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issues first.
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## Instructor Notes
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**Demo script:** If a real Ingress controller is available in the demo environment, run this
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live including the Host-header nuance — students are frequently surprised that `curl <ip>`
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alone doesn't work the way they expect.
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**Approximate timing:** 8-10 minutes live; 5-7 minutes self-paced.
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**Common misconception to preempt:** students often expect an Ingress's IP/address to work like
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a Service's ClusterIP (reachable directly, no extra header needed). Reinforce that Ingress
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routing is fundamentally HOSTNAME/PATH-based, which is exactly what makes one Ingress able to
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route many different domains through one entry point.
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**Optional extension:** ask what would happen if TWO Ingress objects both claimed the same host
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+ path — a good forward pointer to why Ingress configuration conflicts are a real operational
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concern on a shared cluster, without needing to build a hands-on lab around it here.
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# Guided Exercise: Planning Network Isolation
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Paper-and-thinking exercise before the Lab.
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## The scenario
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A `database` Pod (label `app=database`) in the `netpol` namespace should only ever be reachable
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by Pods labeled `role=backend` — not the frontend, not anything else in the cluster.
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## Your task
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1. Before writing any YAML: right now, with NO NetworkPolicy in place, can the frontend reach
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the database? Why?
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2. What would a NetworkPolicy that ONLY specifies `podSelector: { matchLabels: { app: database
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} }` and no `ingress` rules at all do to traffic reaching the database — including from
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`role=backend` Pods?
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3. Sketch (in words, not full YAML) what the `ingress` rule needs to say to allow ONLY
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`role=backend` traffic in.
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4. If a new Pod is later created with `role=backend` in a DIFFERENT namespace, would your policy
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as sketched in #3 allow it? What would need to change if cross-namespace access should be
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allowed?
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## A worked answer to check yourself against
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1. Yes — by default, every Pod can reach every other Pod regardless of labels or namespace
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(ROOT 07's Ingress & NetworkPolicy lesson). Nothing restricts this until a policy exists.
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2. It would block ALL incoming traffic to the database, including from `role=backend` — an
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empty `ingress` list under a policy that selects the Pod means "no traffic is allowed in,"
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not "no policy applies."
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3. An `ingress` rule with `from: [{ podSelector: { matchLabels: { role: backend } } }]` — this
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allows traffic specifically from Pods carrying that label, and nothing else.
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4. Not automatically — a bare `podSelector` in the `from` clause matches Pods in the SAME
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namespace as the policy by default. Allowing a different namespace requires adding a
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`namespaceSelector` alongside the `podSelector` in the same `from` entry.
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## Instructor Notes
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**Facilitation:** Question 2 is the one most likely to trip students up — it directly reinforces
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the "empty ingress rules means deny-all, not no-op" point from the lesson, which is worth
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confirming actually landed before the Lab.
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**Approximate timing:** 10-12 minutes live with discussion; 10 minutes self-paced.
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**Optional extension:** ask what a security-minded team would ALSO want to restrict about this
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database Pod's OWN outbound (egress) traffic, beyond who can reach it — a light forward pointer
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to ROOT 09's security-control framing of NetworkPolicy, without requiring students to build an
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egress rule here.
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# Reflection: Reachability Should Be a Decision, Not a Default
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You just configured real Ingress routing and real network isolation. Take a few minutes to
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connect this to production thinking.
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## Reflection questions
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1. Before this module, would you have assumed a fresh Kubernetes cluster isolates Pods from
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each other by default? Has that changed?
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2. If your team runs a multi-tenant cluster (several unrelated applications sharing it), what's
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the risk of NEVER applying any NetworkPolicy at all?
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3. Ingress lets many different domains share one entry point. What's the operational benefit of
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that beyond just "fewer objects to manage"?
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## Real Ops takeaway
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**"No NetworkPolicy" is not neutral — it's full reachability.** Exactly like an unhardened
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Pod's SecurityContext (ROOT 09 covers this in depth), the absence of a NetworkPolicy isn't a
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safe default; it's the MOST permissive configuration available. On any cluster where more than
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one team or application shares infrastructure, that's a real, often-overlooked exposure.
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**Centralizing external entry points through Ingress reduces attack surface, not just object
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count.** Every separate LoadBalancer Service is a separate externally-reachable endpoint to
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secure, monitor, and patch. Routing through one (or a small number of) Ingress controllers means
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security controls — TLS termination, rate limiting, WAF rules — are configured and audited in
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one place instead of scattered across every application team's own Service definitions.
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This module is complete. Continue to the next module.
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## Instructor Notes
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**Discussion questions for a live classroom:** question 2 is worth pushing on with a concrete
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scenario — ask what a compromised low-value application (a demo app, a staging environment)
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could reach on a cluster with zero NetworkPolicies, versus one with sensible defaults.
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**Approximate timing:** 8 minutes live discussion; 5 minutes self-paced writing.
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**Optional extension:** ask students to sketch (in words) what a reasonable DEFAULT-DENY policy
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for an entire new namespace would look like, before any application-specific allow rules are
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added — previews the security-control framing ROOT 09 builds on.
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