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storageclass-accessor

Contents

Introduction

The storageclass-accessor webhook is an HTTP callback which responds to admission requests.

When creating PVC, it will take out the accessor related to this storage class, and the request will be allowed only when all accessors pass the verification.

Users can create accessors and set namespaceSelector to achieve namespace-level management and/or set workspaceSelector to achieve workspace-level management on the storage class which provisions the PVC.

Installation

Installation by helm-charts

helm install --create-namespace --namespace storageclass-accessor storageclass-accessor main/storageclass-accessor

See the Chart README.md for detailed documentation on the Helm Chart

Quick start

The guide describes how to deploy a storageclass-accessor webhook to a cluster and provides an example accessor based on csi-qingcloud.

1. Install CRD and CR

kubectl create -f  client/config/crds

2. Prepare deployment

./deploy/prepare.sh --namespace xyz

3. Deploy

kubectl apply -f ./deploy

4. Write a CR

Create your accessor according to your needs by referring to Accessor CR and Examples.

5. Apply CR

Use the kubectl apply command to make the accessor you created operational.

6. Test

Now you can try to create a PVC. If it is created in a namespace that is not allowed, the following error will be output:

Error from server: error when creating "PVC.yaml": admission webhook "pvc-accessor.storage.kubesphere.io" denied the request: The storageClass: StorageClassName does not allowed CREATE persistentVolumeClaim PVC-NAME in the namespace: TARGET-NS

Accessor CR

A complete accessor should have the following fields:

  • spec.storageClassName

    The accessor knows the effective sc according to this field.

  • spec.namespaceSelector

    This field is used to fill in the limit of nameSpace, Including labelSelector and fieldSelector.

  • spec.namespaceSelector.fieldSelector

    It is an array of fieldExpressions that manages whether nameSpace is available through the label of nameSpace.

  • fieldExpressions

    It is an array of fieldRule. Every rule in the array needs to be verified.

    labelRule has the following fields:

    1.field: String. Required. Currently supports selection through the "Name" and "Status" fields.
2.operator: String. Required. Currently supports selection through the "In" and "NotIn" fields.
2.values: []String. Required.

  • spec.namespaceSelector.labelSelector

    It is an array of matchExpressions that manages whether nameSpace is available through the label of nameSpace.

  • spec.namespaceSelector.labelSelector.matchExpressions

    It is an array of labelRule. Every rule in the array needs to be verified.

    labelRule has the following fields:

    1.key: String. Required. Currently supports selection through the "Name" and "Status" fields.
2.operator: String. Required. Currently supports selection through the "In" and "NotIn" fields.
2.values: []String. Required.

Examples

The following few examples of yaml may be helpful for you to design your own accessor.

Only fieldSelector

  • Only one fieldExpression
apiVersion: storage.kubesphere.io/v1alpha1
kind: Accessor
metadata:
  name: onlyFieldSelector-accessor
spec:
  storageClassName: "csi-qingcloud"
  namespaceSelector:
    fieldSelector:
      - fieldExpressions:
          - field: "Name"
            operator: "In"
            values: ["NS1"]

After applying this accessor, you can create the PVC of csi-qingcloud only in namespace.name which in this array :["NS1"].

More than one fieldExpressions are allowed in a fieldSelector.

And multiple rules are also allowed in fieldExpressions.

  • Multiple fieldExpressions
apiVersion: storage.kubesphere.io/v1alpha1
kind: Accessor
metadata:
  name: multipleFieldExpressions-accessor
spec:
  storageClassName: "csi-qingcloud"
  namespaceSelector:
    fieldSelector:
      - fieldExpressions:
          - field: "Name"
            operator: "In"
            values: ["NS1"]
      - fieldExpressions:
          - field: "Name"
            operator: "In"
            values: ["NS2", "NS3"]

You can create the PVC of csi-qingcloud in the following namespace: (nameSpace.Name in ["NS1"]) or (nameSpace.Name in ["NS2", "NS3"]).

  • Multiple rules in one fieldExpressions
apiVersion: storage.kubesphere.io/v1alpha1
kind: Accessor
metadata:
  name: multipleFieldExpressions-accessor
spec:
  storageClassName: "csi-qingcloud"
  namespaceSelector:
    fieldSelector:
      - fieldExpressions:
          - field: "Name"
            operator: "NotIn"
            values: ["NS1", "NS2"]
          - field: "Status"
            operator: "In"
            values: ["Active"]

You can create the PVC of csi-qingcloud only in the following namespace: (nameSpace.Name NotIn ["NS1", "NS2"]) and (nameSpace.Status.Status in ["Active"])

It means that the rules in fieldExpressions must be followed at the same time.

Only labelSelector

  • Only one matchExpressions
apiVersion: storage.kubesphere.io/v1alpha1
kind: Accessor
metadata:
  name: csi-qingcloud-accessor
spec:
  storageClassName: "csi-qingcloud"
  namespaceSelector:
    labelSelector:
      - matchExpressions:
          - key: "app"
            operator: "In"
            values: ["app1", "app2"]

This requires nameSpace to have the key "app" label and the value in this array: ["app1", "app2"].

  • Multiple matchExpressions
apiVersion: storage.kubesphere.io/v1alpha1
kind: Accessor
metadata:
  name: multipleFieldExpressions-accessor
spec:
  storageClassName: "csi-qingcloud"
  namespaceSelector:
    labelSelector:
      - matchExpressions:
          - key: "app"
            operator: "In"
            values: ["app1", "app2"]
      - matchExpressions:
          - key: "owner"
            operator: "In"
            values: ["owner1", "owner2"]

You can create the PVC of csi-qingcloud in the following namespace: (have the key "app" label and the value in ["app1", "app2"]) or (have the key "owner" label and the value in ["owner1", "owner2"]).

  • Multiple rule in one FieldExpressions
apiVersion: storage.kubesphere.io/v1alpha1
kind: Accessor
metadata:
  name: multipleFieldExpressions-accessor
spec:
  storageClassName: "csi-qingcloud"
  namespaceSelector:
    labelSelector:
      - matchExpressions:
          - key: "app"
            operator: "In"
            values: ["app1"]
          - key: "role"
            operator: "In"
            values: ["owner1", "owner2"]

You can create the PVC of csi-qingcloud in the following namespace: (have the key "app" label and in the value in ["app1"]) and (have the key "owner" label and the value in ["owner1", "owner2"]).

Both fieldSelector and labelSelector

apiVersion: storage.kubesphere.io/v1alpha1
kind: Accessor
metadata:
  name: csi-qingcloud-accessor
spec:
  storageClassName: "csi-qingcloud"
  namespaceSelector:
    fieldSelector:
      - fieldExpressions:
          - field: "Name"
            operator: "In"
            values: ["NS1", "NS2"]
      - fieldExpressions:
          - field: "Status"
            operator: "In"
            values: ["Active"]
    labelSelector:
      - matchExpressions:
          - key: "app"
            operator: "In"
            values: ["app1"]
          - key: "owner"
            operator: "In"
            values: ["owner1", "owner2"]
      - matchExpressions:
          - key: "app"
            operator: "In"
            values: ["app2", "app3"]

It is allowed to create PVC in a namespace that meets one of the following conditions:

  • (name in ["NS1", "NS2"]) and (have the key "app" label and in the value in ["app1"]) and (have the key "owner" label and the value in ["owner1", "owner2"])
  • (name in ["NS1", "NS2"]) and (have the key "app" label and in the value in ["app2", "app3"])
  • (status.Status in ["Active"]) and (have the key "app" label and in the value in ["app1"]) and (have the key "owner" label and the value in ["owner1", "owner2"])
  • (status.Status in ["Active"]) and (have the key "app" label and in the value in ["app2", "app3"])

Notice

⚠️ Warning: Too many accessors may cause unexpected errors in your webhook. It is recommended that one storage class should correspond to one accessor.