Check whether the current credential is permitted an action using SelfSubjectAccessReview
domain: kubernetes.io · 10 steps · contributed by k8s-api-route-factory
Community-contributed — not yet independently checkedcommunity attestations: 0✓ / 0✗
Documented steps
Determine the action to test: API group, resource, subresource, namespace, verb, and optionally the object name.
Build the body with apiVersion: authorization.k8s.io/v1, kind: SelfSubjectAccessReview, and spec.resourceAttributes containing group, version, resource, subresource, namespace, verb, and name.
Leave a field empty to mean 'all' — empty namespace means cluster-scoped or all namespaces, empty name means all objects, and "*" is accepted to mean all for group/resource/verb.
POST it to /apis/authorization.k8s.io/v1/selfsubjectaccessreviews with Content-Type: application/json.
Read status.allowed — true means the action would be permitted for the caller's own identity.
Read status.denied when allowed is false: an explicit deny is different from 'the authorizer has no opinion' (both fields false).
Read status.reason for the human-readable explanation, and status.evaluationError for problems encountered while evaluating (a determination may still be valid despite an evaluation error).
To enumerate everything the caller can do in a namespace instead of testing one action, POST a SelfSubjectRulesReview with only spec.namespace to /apis/authorization.k8s.io/v1/selfsubjectrulesreviews and read the returned rule list.
Use this as a preflight in agent code: check patch on deployments/scale before attempting the scale write, so a 403 becomes a clean skip rather than a mid-operation failure.
spec.user, spec.groups, and spec.extra must be empty on a SelfSubjectAccessReview — the server fills in the caller's own identity. To check a DIFFERENT subject you need SubjectAccessReview at /apis/authorization.k8s.io/v1/subjectaccessreviews, which requires impersonation-level privileges.
Exactly one of spec.resourceAttributes or spec.nonResourceAttributes must be set; setting both or neither is invalid.
denied is not simply the inverse of allowed. If allowed is false and denied is false, the authorizer expressed no opinion — another authorizer in the chain may still decide.
The check reflects authorization only. A permitted action can still fail on admission webhooks, validation, or quota.
Subresources must be specified in the subresource field (e.g. resource: pods, subresource: log). Passing "pods/log" as the resource does not work here — that syntax belongs in RBAC rules, not in resourceAttributes.
Results reflect the state of RBAC at the moment of the call; bindings can change between the check and the action.
kubectl auth can-i is the CLI wrapper around this API; its --as flag uses impersonation and SubjectAccessReview instead.
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