Troubleshooting RBAC Issues

Troubleshooting RBAC Issues

RBAC troubleshooting requires systematic approaches to identify why permissions fail or succeed unexpectedly. Common issues include incorrect subject names, namespace mismatches, and overlooked ClusterRoleBindings. The kubectl auth can-i command provides basic permission checking, but complex scenarios require deeper investigation.

Subject name mismatches cause many RBAC failures. OIDC prefixes, certificate formats, and case sensitivity create subtle differences between expected and actual subject names. Audit logs show exact subject names used in authorization decisions. Comparing these with RBAC bindings reveals mismatches. Consistent naming conventions prevent these issues.

# RBAC troubleshooting commands
# Check specific permission
kubectl auth can-i create pods --namespace=production

# Check permissions as another user
kubectl auth can-i create pods --namespace=production [email protected]

# Check permissions as service account
kubectl auth can-i get secrets --namespace=production \
  --as=system:serviceaccount:production:app-sa

# List all permissions for current user
kubectl auth can-i --list --namespace=production

# Describe RBAC bindings for investigation
kubectl describe rolebinding,clusterrolebinding -A | grep -A5 -B5 alice

# Use impersonation to test permissions
kubectl get pods --namespace=production \
  [email protected] \
  --as-group=developers \
  --as-group=team-alpha

# Analyze audit logs for RBAC denials
kubectl logs -n kube-system kube-apiserver-master-1 | \
  grep -E "authorization.k8s.io/decision=\"deny\""

Permission precedence creates unexpected authorization results. When multiple ClusterRoleBindings or RoleBindings apply, any single "allow" grants permission. This differs from traditional ACL systems where denies take precedence. Understanding this union behavior helps explain why users have unexpected permissions. Regular RBAC cleanup removes obsolete bindings that grant unintended access.