HashiCorp SRE / Platform Engineer interview questions

The Terraform question that actually filters. Everyone knows both meta-arguments exist; the answer is about how state addresses resources, and why an index is a fragile key.

Everyone can say state maps config to reality. The follow-up that separates candidates is what else is in the file, and what that means for who may read it.

Everyone answers state locking. The follow-up is what happens when locking is not configured, and what you do with a stale lock at 2am, which is where the answer gets real.

State layout needs an access boundary. Separate environment credentials and restrict who can assume them; a directory name cannot contain a mistaken apply.

The services-market question that decides who can actually run a migration. Import is the easy part; the hard parts are resource-for-resource fidelity and proving the first plan is empty.

Drift is a governance problem wearing a tooling costume. Detection is easy; the scored content is attribution (who changed it and why) and the policy decision that most teams avoid making.

Extract too early and you maintain a wrapper nobody thanks you for. Here is the extraction trigger, the semver contract that maps onto Terraform surfaces, and the parallel-release path for breaking changes.

Everyone recites that depends_on forces ordering. The stronger half of the answer is the graph you never see: implicit edges from references, why file layout orders nothing, and what explicit edges cost.

HashiCorp calls provisioners a last resort and expects you to say why in concrete terms: tainted resources, invisible drift, SSH reachability. Then name what replaces each legitimate use.

The table is half the answer. The other half is who holds credentials, who repairs a stuck lock at night, and why the boring option usually wins until RBAC demands grow teeth.

sensitive = true stops the echo, not the storage. The complete answer walks the value through git, plan artifacts, state, and provider side effects, naming which mitigation closes which leak.

A green plan is evidence, not proof. Build the pyramid: lint in seconds, policy on every PR, real-cloud verification only where shared modules and money justify the burn.

One ForceNew attribute turns an edit into a destroy. Know the schema mechanics, the four lifecycle levers, and why create_before_destroy trades downtime for name collisions.

Three lifecycle arguments influence replacement and drift handling: create_before_destroy, prevent_destroy, and ignore_changes. Each earns its place through an incident story, and each has a failure mode interviewers wait to hear you name.

Managed platforms sell governance, not execution: locked state with RBAC, plans on every pull request, and audit logs. Price them per resource under management against the engineering hours self-hosting quietly burns.

OpenTofu is the Linux Foundation fork of Terraform 1.5 under MPL, drop-in compatible for most code, with distinct features such as native state encryption. Removed blocks and provider mocking also exist in Terraform. Portability survives by pinning version floors and testing both binaries in CI.

state rm, import, moved and removed blocks each treat a different wound. The senior signal is not reciting commands, it is the backup, lock and plan ritual wrapped around touching production state.

Generation works when the inputs are genuinely data and dies when YAML grows loops. The line between encoding decisions and writing a worse programming language is where these interviews are actually scored.

A mock can confirm that a module requests private storage while missing the IAM denial that stops creation. Separate configuration contracts from provider behavior, and make the costly tests deliberate.

It sounds like trivia and screens for something real: whether you understand that a pod is a shared namespace boundary with an owner, not just a group of containers.

Applications roll back by redeploying; modules cannot unapply state. The asymmetry that forces expand-contract discipline and plan-reviewed upgrades instead of promote-and-rollback pipelines.

The outage window closed, but every process born since then still tries to fetch secrets at boot with nothing to fall back on. Why restarts keep reopening an incident that already ended.

Leases prevent dead holders but not overlapping ones. The staff-level answer is fencing tokens and a candid account of why quorum lock services without downstream checks are still probabilistic.

This is a machine identity problem wearing a secrets costume. Candidates who start at encryption miss that authentication of the caller and delivery mechanics are the real design space.

Drawing an agent that polls a server is the easy third. The interview is about partial applies, fleet-versus-world state, and why rollback must be a pointer flip, never a reverse edit.

Generated infrastructure code is plausible, fluent and confidently wrong in specific ways. The volume goes up, the reviewer attention per line goes down, and the controls that used to be optional stop being optional.

Asked in almost every cloud screen, and most candidates recite the table without ever naming the failure it causes. The ephemeral port range is the whole answer.

Turns the standard autoscaling definition into the problem it actually causes. Almost every candidate can define an HPA; far fewer can say why theirs did not save them.

The question that separates console users from people who have debugged a permissions failure across accounts. Evaluation order is deterministic and knowing it makes AccessDenied readable.

A design question with a clear answer at this scale, and the reasoning is what scores. The three options solve different problems and peering and Transit Gateway connect networks while PrivateLink exposes services.

Most candidates can sell serverless. The question asks you to argue against it, which needs a real understanding of the execution model rather than the marketing.

Trace the route and return path before changing rules. First establish whether the failing connection uses IPv4, IPv6 or a private service endpoint.

The junior-filter question that still separates candidates who understand the model from those who memorised a definition. The answer is three mechanical differences and one economic one.

S3 access failures are rarely about the bucket policy alone. The caller, object ownership and network path determine which authorization checks apply. Start with the failed request and trace changes across those boundaries.