knative-storage-migrate-fips

Chainguard Container for knative-storage-migrate-fips

Migrates the storage version of Knative resources

Chainguard Containers are regularly-updated, secure-by-default container images.

Download this Container Image

For those with access, this container image is available on cgr.dev:

docker pull cgr.dev/ORGANIZATION/knative-storage-migrate-fips:latest

Be sure to replace the ORGANIZATION placeholder with the name used for your organization's private repository within the Chainguard Registry.

Compatibility Notes

Chainguard's knative-storage-migrate-fips image is comparable to the official Knative Migrate image (gcr.io/knative-releases/knative.dev/pkg/apiextensions/storageversion/cmd/migrate), and can be used as a drop-in replacement.

FIPS Support

This Chainguard Container ships with a validated redistribution of OpenSSL's FIPS provider module. For more on FIPS support in Chainguard Containers, refer to the guide on FIPS-enabled Chainguard Images on Chainguard Academy.

Getting Started

knative-storage-migrate-fips is a tool for migrating Kubernetes Custom Resource objects to a new storage version after upgrading a Custom Resource Definition (CRD). Although this tool is part of the Knative project, it is not limited to Knative resources: it works with any CRD in your cluster.

When you add a new storage version to a CRD, existing objects in etcd are still stored under the old version. This tool re-writes those objects so that etcd reflects the current storage version, allowing you to safely remove the old version from your CRD.

Prerequisites

• A running Kubernetes cluster with kubectl configured
• A CRD to migrate (see the walkthrough below for an example setup)

Walkthrough

1. Install a CRD with an initial storage version

Start with a CRD that uses v1alpha1 as its storage version.

kubectl apply -f - <<EOF
apiVersion: apiextensions.k8s.io/v1
kind: CustomResourceDefinition
metadata:
  name: widgets.example.com
spec:
  group: example.com
  names:
    kind: Widget
    plural: widgets
  scope: Namespaced
  versions:
  - name: v1alpha1
    served: true
    storage: true
    schema:
      openAPIV3Schema:
        type: object
EOF

kubectl wait --for=condition=Established crd/widgets.example.com --timeout=30s

2. Create an object using v1alpha1

kubectl apply -f - <<EOF
apiVersion: example.com/v1alpha1
kind: Widget
metadata:
  name: test-widget
  namespace: default
EOF

At this point, test-widget is stored in etcd under v1alpha1.

3. Upgrade the CRD to add v1 as the new storage version

When upgrading the CRD, set storage: false on v1alpha1 and storage: true on v1. Both versions should remain served: true during migration so that existing objects are still accessible.

kubectl apply -f - <<EOF
apiVersion: apiextensions.k8s.io/v1
kind: CustomResourceDefinition
metadata:
  name: widgets.example.com
spec:
  group: example.com
  names:
    kind: Widget
    plural: widgets
  scope: Namespaced
  versions:
  - name: v1alpha1
    served: true
    storage: false
    schema:
      openAPIV3Schema:
        type: object
  - name: v1
    served: true
    storage: true
    schema:
      openAPIV3Schema:
        type: object
EOF

kubectl wait --for=condition=Established crd/widgets.example.com --timeout=30s

After this step, status.storedVersions on the CRD will contain both v1alpha1 and v1 because existing objects have not yet been migrated. You can verify this by running:

$ kubectl get crd widgets.example.com -o jsonpath='{.status.storedVersions}'
["v1alpha1", "v1"]

4. Set up RBAC for the migration job

The migration job needs permission to read and update your custom resources, as well as to patch the CRD status (to update storedVersions after migration completes).

kubectl apply -f - <<EOF
apiVersion: v1
kind: ServiceAccount
metadata:
  name: storage-version-migration
  namespace: default
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: storage-version-migration
rules:
  - apiGroups: ["example.com"]
    resources: ["widgets"]
    verbs: ["get", "list", "update", "patch"]
  - apiGroups: ["apiextensions.k8s.io"]
    resources: ["customresourcedefinitions"]
    verbs: ["get", "list"]
  - apiGroups: ["apiextensions.k8s.io"]
    resources: ["customresourcedefinitions/status"]
    verbs: ["patch", "update"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: storage-version-migration
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: storage-version-migration
subjects:
  - kind: ServiceAccount
    name: storage-version-migration
    namespace: default
EOF

5. Run the migration job

Use the knative-storage-migrate-fips image to run the migration job. Pass the fully-qualified CRD name as an argument to the migration container. The job will list all existing objects and re-write them, causing the API server to store them under the new storage version.

kubectl apply -f - <<EOF
apiVersion: batch/v1
kind: Job
metadata:
  name: storage-version-migration
  namespace: default
spec:
  backoffLimit: 3
  template:
    spec:
      serviceAccountName: storage-version-migration
      restartPolicy: OnFailure
      containers:
        - name: migrate
          image: cgr.dev/ORGANIZATION/knative-storage-migrate-fips
          args:
            - "widgets.example.com"
EOF

kubectl wait --for=condition=Complete job/storage-version-migration --timeout=60s

Once the job completes, status.storedVersions on the CRD will contain only v1, confirming that all objects have been migrated.

$ kubectl get crd widgets.example.com -o jsonpath='{.status.storedVersions}'
["v1"]

Documentation and resources

• knative/pkg — The Knative common packages repository, which contains the source for the migrate binary (apiextensions/storageversion).
• Knative documentation

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