Design and validate a small internal platform contract that turns a developer service request into owned, policy-compliant, observable desired state with a rollback path and measurable platform outcome.
A product team needs a standard web service path. Today they file tickets for repository setup, namespace access, deployment wiring, dashboards and policy exceptions. Build a platform contract that reduces those handoffs while preserving ownership and safe controls.
The service owner in the request must match catalog ownership; the artifact digest promoted by desired state must match the built artifact; public exposure requires an explicit policy decision; readiness requires dashboard, SLO, runbook and rollback evidence.
The evidence chain should also identify the build platform owner, the immutable artifact/SBOM/provenance hand-off, workload identity or secret-delivery boundary, and the incident/support owner for the platform capability.
The final evidence should show not only that automation ran, but that a developer can request, understand, operate and recover the service without hidden platform-team steps.
developer request → catalog → golden path → bounded environment → immutable artifact → desired state → policy → runtime/readiness → feedbackGoal: Create a relationship-aware platform manifest and prove that unsafe or inconsistent changes are rejected.
mkdir -p /tmp/platform-capstone
cat > /tmp/platform-capstone/platform.json <<'EOF'
{"request":{"service":"orders","owner":"payments","environment":"prod","workload_class":"web-service"},"catalog":{"service":"orders","owner":"payments","docs":true},"artifact":{"digest":"sha256:abc123","signed":true},"desired":{"artifact_digest":"sha256:abc123","replicas":3},"policy":{"privileged":false,"public":false,"exception_days":0},"readiness":{"dashboard":true,"slo":true,"runbook":true,"rollback":true},"platform":{"self_service":true,"idempotent":true,"status_visible":true,"support_owner":"platform"}}
EOFpython3 labs/platform-engineering-capstone/validate_platform.py /tmp/platform-capstone/platform.jsonpython3 - <<'PY2'
import json
p='/tmp/platform-capstone/platform.json'; x=json.load(open(p)); x['desired']['artifact_digest']='sha256:DIFFERENT'; json.dump(x,open('/tmp/platform-capstone/bad.json','w'))
PY2
if python3 labs/platform-engineering-capstone/validate_platform.py /tmp/platform-capstone/bad.json; then echo 'ERROR: drift was accepted'; exit 1; else echo 'expected rejection: artifact drift'; fiExplain which implementation details the developer does not need to know, and which evidence/status must remain visible for safe operations.
A production platform is an interface across many systems; the capstone tests whether those interfaces form one coherent, operable developer journey.
Map the same contract to Backstage/catalog/templates, GitHub/GitLab, Terraform/OpenTofu, Helm, Argo CD/Flux, Kubernetes policy and observability in an approved sandbox.
printf '%s
' 'Backstage -> request/catalog/template' 'IaC -> environment' 'Helm -> workload package' 'GitOps -> desired state/reconciliation' 'Policy -> admission/guardrails' 'Observability -> readiness/feedback'A clear target user journey, baseline friction and measurable outcome.
Service identity, owner, lifecycle and documentation/runbook links are explicit.
Validated inputs/outputs, supported defaults, extension path and versioning semantics.
Idempotent lifecycle, immutable artifact promotion, desired-state reconciliation and rollback. Build-platform ownership and artifact/SBOM/provenance hand-off are explicit.
Least privilege, quotas/ownership, guardrails and bounded exceptions are proven. Workload identity/secret-delivery boundaries are explicit.
Dashboards/signals, SLO/readiness evidence and actionable scorecard rules.
Platform SLOs, adoption/task-success signals, support and deprecation strategy. On-call, intake/roadmap and incident handoff boundaries are explicit.
Three concept checks plus one scenario check.
A coherent supported developer contract connects capabilities, guardrails, ownership, lifecycle and feedback across the tools.
Ownership is part of the operational contract; conflicting sources make routing and accountability unreliable.
It proves the exact immutable artifact is the one promoted through the platform path.
No. Provisioning succeeded, but the production operational-readiness contract is incomplete.
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Attempt the core lab and knowledge checks before marking the module complete.