Cheat sheet & self-check

Pick an answer to see if you got it, and why.

1. Q1. Why use OIDC federation from CI instead of storing AWS access keys as secrets?

   1. AIt's faster
   2. BNo long-lived keys to leak; credentials are short-lived and the role trusts only specific repos, branches or environments
   3. CKeys don't work in CI
   4. DIt's free
   Show answer

   B. The CI provider issues a signed token per job; AWS exchanges it for temporary credentials if the trust conditions match.

   From lesson 10 · CI/CD for the stack

2. Q2. Why separate the plan role from the apply role?

   1. AFor speed
   2. BPull requests (including from less-trusted branches) only get read-only access; only the protected main-branch job can change infrastructure
   3. CAWS requires it
   4. DTo save money
   Show answer

   B. A malicious or buggy PR shouldn't be able to modify production just by running a plan job.

   From lesson 10 · CI/CD for the stack

3. Q3. What should apply use?

   1. AA fresh plan made at apply time
   2. BThe saved plan file that was reviewed, so what's applied is exactly what was approved
   3. Cterraform apply -auto-approve on every branch
   4. DThe console
   Show answer

   B. Applying a saved plan prevents surprises when something changed between review and apply.

   From lesson 10 · CI/CD for the stack

4. Q4. Someone ran 'terraform destroy' in the wrong workspace, and the state now shows nothing, but the resources were only partly deleted. First step?

   1. ARun apply immediately
   2. BStop all runs, back up the current state, inspect what actually exists in AWS, then restore or re-import deliberately
   3. CDelete the bucket
   4. DRecreate the account
   Show answer

   B. Acting fast without understanding can make it worse. Freeze changes, preserve evidence, compare state with reality, then recover.

   From lesson 11 · Disaster recovery

5. Q5. Why does versioning on the state bucket matter?

   1. AIt's cheaper
   2. BEvery state write creates a version, so a corrupted or wrong state can be rolled back to a known-good one
   3. CIt encrypts the state
   4. DIt speeds up plans
   Show answer

   B. Versioning is the undo button for state. Combine it with locking and restricted access.

   From lesson 11 · Disaster recovery

6. Q6. What lets you rebuild an EKS cluster's workloads quickly after losing the cluster?

   1. AScreenshots
   2. BCluster and platform defined in Terraform, apps in GitOps, data in backups (Velero, database backups) and secrets in a secret manager
   3. CAn etcd snapshot of the managed control plane
   4. DNothing
   Show answer

   B. EKS doesn't give you etcd snapshots; your recovery path is declarative code plus data backups.

   From lesson 11 · Disaster recovery

7. Q7. What makes a platform 'hand-over ready'?

   1. AIt runs
   2. BAnother team can operate it from documentation: runbooks, SLOs, access model, upgrade and DR procedures, with evidence they work
   3. CIt uses the newest versions
   4. DIt has no alerts
   Show answer

   B. Operability is part of the deliverable. If only the builder can run it, it isn't finished.

   From lesson 12 · Capstone: own, harden & operate