Migrate CertificateSigningRequest from certificates.k8s.io/v1beta1

CertificateSigningRequest asks the cluster to sign a certificate. Kubernetes 1.22 removed certificates.k8s.io/v1beta1. In v1, signerName and usages are required, so every request must name the signer that should handle it.

The error

After the upgrade to 1.22, kubectl apply fails like this:

error: resource mapping not found for name: "<name>" namespace: "<ns>" from "<file>": no matches for kind "CertificateSigningRequest" in version "certificates.k8s.io/v1beta1"
ensure CRDs are installed first

What replaces it

Replacement: certificates.k8s.io/v1
Available since: 1.19
Deprecated in: 1.19
Removed in: 1.22

Check a manifest against 1.22, or read the official documentation.

Migration notes

spec.signerName is now required, and requests for kubernetes.io/legacy-unknown are not allowed to be created via the certificates.k8s.io/v1 API
spec.usages is now required, may not contain duplicate values, and must only contain known usages
status.conditions may not contain duplicate types
status.conditions[*].status is now required
status.certificate must be PEM-encoded, and contain only CERTIFICATE blocks

Before and after

Before:

apiVersion: certificates.k8s.io/v1beta1
kind: CertificateSigningRequest
metadata:
  name: jane
spec:
  request: <base64-encoded CSR>
  usages:
    - client auth

After:

apiVersion: certificates.k8s.io/v1
kind: CertificateSigningRequest
metadata:
  name: jane
spec:
  request: <base64-encoded CSR>
  signerName: kubernetes.io/kube-apiserver-client
  usages:
    - client auth

Helm upgrade fails after a cluster upgrade

If you installed this with Helm, helm upgrade can fail after the cluster is upgraded, even if the chart is already fixed. Which error appears depends on your Helm version and the error text:

Error: UPGRADE FAILED: unable to build kubernetes objects from current release manifest: resource mapping not found for name: "<name>" namespace: "<ns>" from "": no matches for kind "CertificateSigningRequest" in version "certificates.k8s.io/v1beta1"

Error: UPGRADE FAILED: current release manifest contains removed kubernetes api(s) for this kubernetes version and it is therefore unable to build the kubernetes objects for performing the diff. error from kubernetes: unable to recognize "": no matches for kind "CertificateSigningRequest" in version "certificates.k8s.io/v1beta1"

Helm compares your chart with the manifest stored with the release. That stored manifest still has the old API, and the cluster can no longer read it.

To check, get the stored manifest, and paste the output into the checker:

helm get manifest <release> -n <namespace>

To fix the stored record, use the helm-mapkubeapis plugin, latest tag v0.6.1. Try --dry-run first. Its README lists support for Helm v3, so check that it suits your Helm version.

helm plugin install https://github.com/helm/helm-mapkubeapis --version v0.6.1
helm mapkubeapis <release> --namespace <namespace> --dry-run

Helm's advice is to move releases to supported APIs before you upgrade the cluster, and not to roll back to a release from before that change.