Kubernetes Helm Interview Questions
Reviewed by Mark Dickie · Last updated
5 questions on this page you can answer and see marked on the spot. Go to the first one
Helm is a package manager for Kubernetes that bundles manifests into reusable units called charts and manages their lifecycle as versioned releases. For a Helm-focused k8s operations interview, you should know chart anatomy (Chart.yaml, values.yaml, templates/), how the template engine renders Go templates against values and built-in objects, and how helm install, upgrade, rollback, and uninstall map to release states stored in the cluster.
You should also be comfortable with values layering (default → values.yaml → --set → -f overrides), chart dependencies and subcharts, the role of _helpers.tpl for named templates, hooks for pre/post-install jobs, and the differences between Helm v2 (Tiller server component) and v3 (client-only, three-way strategic merge patches). Interviewers often probe how you handle secrets in values, manage chart repositories, and integrate Helm into a GitOps workflow with tools like Argo CD or Flux.
What does a Helm interview test?
| Area | What gets asked |
|---|---|
| Chart structure | Chart.yaml fields, template files, values.yaml defaults |
| Release lifecycle | install vs upgrade, rollback to a previous revision, release history |
| Templating | Go template functions, {{ range }}, {{ if }}, named templates in _helpers.tpl |
| Values management | override precedence, subchart values, --set vs -f |
| Production concerns | secrets handling, CRDs, three-way merge patches, hooks |
| Ecosystem | chart repositories, OCI registries, GitOps integration |
Key concepts worth reviewing before the quiz:
- How Helm v3 stores release metadata as Secrets in the release namespace (no Tiller, no server-side component).
- The override precedence chain: built-in defaults, chart values.yaml, parent chart values,
--setflags on the CLI. - Why
helm upgradewithout--installfails on a missing release, and how--atomicrolls back on error. - How hooks (pre-install, post-upgrade, etc.) run as Jobs or Pods outside the normal render-then-apply flow.
- The difference between
helm template(local render, dry-run) andhelm install(server-side apply with validation).
Key facts
- Tarmac has 13 Kubernetes interview questions on this topic, 10 of them on this page, at difficulty 1–5 of 5.
- Tarmac tracked 2,661 job postings asking for Kubernetes in September 2026.
- Roles asking for Kubernetes advertise a median base salary of £80,000, across 868 job postings as of September 2026.
- Tarmac last reviewed these Kubernetes interview questions on 14 September 2026.
At a glance
| Questions | 10 shown · 13 in the bank |
|---|---|
| Difficulty | 1–5 of 5 |
| Formats | Multiple choice, Ordering, Multiple answer, Fill in the blank, True / false, Short answer, Flashcard |
What you'll review
- helm
Practice questions
Try one before you open the answer. Pick an option and press Check; it's marked on the spot.
You want to see every past revision of a Helm release named web in the current namespace, including each revision's status and chart version. Which command does this?#
Options
Show answer
The command helm history <release> lists every revision of a Helm release. Each row shows the revision number, last update time, status, and chart version, which is what you need before a rollback. Other Helm commands report only current state or list releases instead.
helm history <release> prints the revision table for a release: one row per revision with its revision number, update time, status, chart name and version, and description. helm status only reports the current state of the latest revision, helm get notes prints the chart's NOTES text, and helm list --all lists releases across the cluster rather than revisions of one release.
In Helm, what is a chart?#
Options
Show answer
A Helm chart is a package of templated Kubernetes manifests. It bundles a Chart.yaml metadata file, default values.yaml settings, and a templates/ directory. Helm renders the templates with supplied values and applies the result to the cluster as a release.
A Helm chart is a directory-based package containing a Chart.yaml metadata file, a values.yaml file with default configuration, and a templates/ directory of Kubernetes manifests written as Go templates. Helm renders those templates using values supplied at install or upgrade time and then applies the resulting manifests to the cluster as a release. The other choices describe a container registry, a Kubernetes controller, and an interactive editing tool, none of which is a chart.
You are managing a release named myapp from a chart in ./chart. Put these Helm commands in the order they occur in the following scenario (earliest first): the release is first created, then its image is upgraded to tag 2.0, the 2.0 build turns out to be broken so you roll back to the prior revision, and finally the release is decommissioned.#
Put these in order
Show answer
The correct order is: helm install myapp ./chart, then helm upgrade myapp ./chart --set image.tag=2.0, then helm rollback myapp 1, then helm uninstall myapp. The install creates the release (revision 1); the upgrade to 2.0 creates revision 2; the rollback restores the prior revision while the release still exists; and the uninstall removes the release and its history, so it must come last.
The scenario pins the sequence. helm install creates the release and records revision 1, so it must come first — the other commands act on an existing release. helm upgrade myapp ./chart --set image.tag=2.0 records revision 2 with the new image tag and must precede the rollback because the rollback is specifically to recover from this broken 2.0 upgrade. helm rollback myapp 1 restores revision 1's configuration and creates a new revision while the release still exists. helm uninstall removes the release and its revision history, so it must come last — a rollback after uninstall would fail unless --keep-history was passed.
Which of the following statements about Helm 3 release management are correct? Select all that apply.#
Options
Pick every one that applies.
Show answer
Helm 3 keeps release revisions as Kubernetes Secrets in the release's namespace by default. Rolling back to an earlier revision does not erase history; it deploys that revision again as a new entry in helm history. Helm 3 needs no Tiller component, and helm template only renders manifests locally.
Helm 3 stores each release revision as a Secret (type helm.sh/release.v1) in the release's namespace by default, so release state lives in the cluster without a server-side component. A rollback does not rewrite history; it deploys the chosen earlier revision as a new revision, which appears in helm history with a higher number. The statement about helm template is wrong because it only renders manifests locally and creates no release or cluster resources. The Tiller statement describes Helm 2's architecture, which Helm 3 removed.
To preview the manifests Helm would render for a release named web from the chart at ./mychart without creating any resources in the cluster, run helm install web ./mychart --_____. Fill in the missing flag name (without leading dashes, in lowercase).#
Show answer
To preview the manifests Helm would render for a release named web from the chart at ./mychart without creating any resources in the cluster, run helm install web ./mychart --**dry-run**. Fill in the missing flag name (without leading dashes, in lowercase).
Helm's install command accepts a dry-run flag that renders the chart's templates and reports the resulting manifests without installing the release or creating any resources. The flag is spelled dry-run, so the blank is filled with dry-run (written on the command line as --dry-run).
In Helm 3, running helm rollback myapp 2 on a release currently at revision 3 deletes revision 3 from the release history.#
Options
Show answer
No. In Helm 3, helm rollback never deletes newer revisions. It re-applies the target revision's manifests and values as a new revision at the top of the release history, so after rolling back from revision 3 to revision 2, helm history shows revision 4 and still lists revisions 1 through 3.
False. helm rollback does not delete any revisions. It takes the manifests and values of the target revision (revision 2) and applies them as a new revision on top of the history, so the release moves to revision 4. Revisions 1 through 3 remain visible in helm history. Only the separate --history-max pruning mechanism removes old revisions, and rollback does not trigger that deletion of the newer revision.
A teammate runs helm upgrade my-app ./chart --atomic --timeout 5m against an existing release, and the upgrade fails because a Deployment never becomes ready. In 3-5 sentences, explain (1) what --atomic does to the release when the upgrade fails, including its relationship to --wait and to the revision history, and (2) one concrete category of side effect that --atomic does NOT undo. Assume Helm 3.#
Show answer
--atomic implies --wait, so Helm waits for the release's resources to become ready within the timeout. If the upgrade fails, Helm automatically rolls the release back to the previous successful revision; this rollback is recorded as a new revision number rather than deleting history. It does not undo external side effects such as a database schema migration run by a Job, data written by the application, or changes to resources outside the release's manifests, because Helm only reverts the Kubernetes objects it manages in that release.
With Helm 3, --atomic turns on waiting for resources to become ready (it implies --wait). If the upgrade fails or times out, Helm performs a rollback to the last successful revision of the release, which creates a new revision entry in the history. Rollback only restores the manifests Helm manages for that release, so anything applied outside those manifests, such as data changes or migrations executed by a Job that already completed, is not reverted and must be handled separately (for example with backward-compatible migrations).
In Helm 3, what does helm upgrade --atomic do when the upgrade fails, and how does it differ from using --wait alone? Answer in two or three sentences.#
Show answer
--atomic implies --wait, so Helm waits for the release's resources to become ready within the timeout. If the upgrade fails (for example, resources never become ready or a hook fails), --atomic automatically rolls the release back to the previous successful revision. --wait alone only blocks until readiness and, on failure, leaves the release in a failed state with no automatic rollback.
The --atomic flag builds on --wait: it waits for resources to become ready, and if the upgrade does not succeed it triggers an automatic rollback to the last successful revision. The key distinction is that --wait only blocks and reports, while --atomic also reverts the release state on failure. A strong answer names both the implied wait and the automatic rollback, and says --wait alone does not roll back.
In Helm 3 (default storage driver), where is the state for each release revision stored, and what is the format of that record? Name the Kubernetes object type, its naming pattern, and how the payload is encoded.#
Show answer
Each revision is stored as a Kubernetes Secret of type helm.sh/release.v1 in the release's namespace, named sh.helm.release.v1.<release>.v<revision>. The release key holds the serialized release record (JSON of the release object), gzip-compressed and then base64-encoded, which is how Helm reads history and performs rollbacks.
Helm 3 removed Tiller and defaults to the secret storage driver, so release history lives in the cluster as Secrets rather than in a server-side component. Each upgrade or install writes a new Secret with an incremented revision suffix. The payload is the serialized release (manifest, values, chart metadata, status), gzip-compressed and base64-encoded as required for Secret data handling. Knowing this explains why history is tied to the namespace the release was installed into and why large charts can hit the Secret size limit of about 1 MiB.
Helm 3 stores each release revision as a Kubernetes object in the release's namespace: a Secret whose type is _____. Each such Secret carries the label _____=helm, which is how helm list and helm history find them.#
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Helm 3 stores each release revision as a Kubernetes object in the release's namespace: a Secret whose type is helm.sh/release.v1. Each such Secret carries the label owner=helm, which is how helm list and helm history find them.
Since Helm 3 the default release storage driver is secret. Each revision is saved as a Secret named sh.helm.release.v1.<release>.v<revision> with the type helm.sh/release.v1. The Secret is labelled owner=helm, along with labels such as name, version, and status, which Helm uses to query release history. The release data is a gzipped, base64-encoded Release object containing the rendered manifests and values.
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