Cannot use BackendConfig on GKE - kubernetes

Question

I have an application that I can deploy to kubernetes (Google Kubernetes Engine) to which I'm trying to add Google's CDN. For this I'm adding a BackendConfig. But when my gitlab pipeline tries to apply it it returns the following error.
$ kubectl apply -f backend-config.yaml
Error from server (Forbidden): error when retrieving current configuration of:
Resource: "cloud.google.com/v1beta1, Resource=backendconfigs", GroupVersionKind: "cloud.google.com/v1beta1, Kind=BackendConfig"
I have a strongly suspect that the account the pipeline is running under does not have enough privileges to access backend configs. Being new to k8s and gke I'm not sure how to fix this. Especially as I cannot find what permission is needed for this.
Edit
I added a kubectl get backendconfigs to my pipeline and that fails with the same error. Running it from my gcloud sdk environment the same command works.
Note the cluster is managed by Gitlab and using RBAC. My understanding is that gitlab creates service accounts per namespace in k8s with the edit role.
Edit 2
Added ClusterRole and ClusterRoleBinding based on Arghya's answer.
Output of $ kubectl get crd
NAME CREATED AT
backendconfigs.cloud.google.com 2020-01-09T15:37:27Z
capacityrequests.internal.autoscaling.k8s.io 2020-04-28T11:15:26Z
certificaterequests.cert-manager.io 2020-01-15T06:53:47Z
certificates.cert-manager.io 2020-01-15T06:53:48Z
challenges.acme.cert-manager.io 2020-01-15T06:53:48Z
challenges.certmanager.k8s.io 2020-01-09T15:47:01Z
clusterissuers.cert-manager.io 2020-01-15T06:53:48Z
clusterissuers.certmanager.k8s.io 2020-01-09T15:47:01Z
issuers.cert-manager.io 2020-01-15T06:53:48Z
issuers.certmanager.k8s.io 2020-01-09T15:47:01Z
managedcertificates.networking.gke.io 2020-01-09T15:37:53Z
orders.acme.cert-manager.io 2020-01-15T06:53:48Z
orders.certmanager.k8s.io 2020-01-09T15:47:01Z
scalingpolicies.scalingpolicy.kope.io 2020-01-09T15:37:53Z
updateinfos.nodemanagement.gke.io 2020-01-09T15:37:53Z
Output of kubectl describe crd backendconfigs.cloud.google.com
Name: backendconfigs.cloud.google.com
Namespace:
Labels: <none>
Annotations: <none>
API Version: apiextensions.k8s.io/v1beta1
Kind: CustomResourceDefinition
Metadata:
Creation Timestamp: 2020-01-09T15:37:27Z
Generation: 1
Resource Version: 198
Self Link: /apis/apiextensions.k8s.io/v1beta1/customresourcedefinitions/backendconfigs.cloud.google.com
UID: f0bc780a-32f5-11ea-b7bd-42010aa40111
Spec:
Conversion:
Strategy: None
Group: cloud.google.com
Names:
Kind: BackendConfig
List Kind: BackendConfigList
Plural: backendconfigs
Singular: backendconfig
Scope: Namespaced
Validation:
Open APIV 3 Schema:
Properties:
API Version:
Description: APIVersion defines the versioned schema of this representation of an object. Servers should convert recognized schemas to the latest internal value, and may reject unrecognized values. More info: https://git.k8s.io/community/contributors/devel/api-conventions.md#resources
Type: string
Kind:
Description: Kind is a string value representing the REST resource this object represents. Servers may infer this from the endpoint the client submits requests to. Cannot be updated. In CamelCase. More info: https://git.k8s.io/community/contributors/devel/api-conventions.md#types-kinds
Type: string
Metadata:
Type: object
Spec:
Description: BackendConfigSpec is the spec for a BackendConfig resource
Properties:
Cdn:
Description: CDNConfig contains configuration for CDN-enabled backends.
Properties:
Cache Policy:
Description: CacheKeyPolicy contains configuration for how requests to a CDN-enabled backend are cached.
Properties:
Include Host:
Description: If true, requests to different hosts will be cached separately.
Type: boolean
Include Protocol:
Description: If true, http and https requests will be cached separately.
Type: boolean
Include Query String:
Description: If true, query string parameters are included in the cache key according to QueryStringBlacklist and QueryStringWhitelist. If neither is set, the entire query string is included and if false the entire query string is excluded.
Type: boolean
Query String Blacklist:
Description: Names of query strint parameters to exclude from cache keys. All other parameters are included. Either specify QueryStringBlacklist or QueryStringWhitelist, but not both.
Items:
Type: string
Type: array
Query String Whitelist:
Description: Names of query string parameters to include in cache keys. All other parameters are excluded. Either specify QueryStringBlacklist or QueryStringWhitelist, but not both.
Items:
Type: string
Type: array
Type: object
Enabled:
Type: boolean
Required:
enabled
Type: object
Connection Draining:
Description: ConnectionDrainingConfig contains configuration for connection draining. For now the draining timeout. May manage more settings in the future.
Properties:
Draining Timeout Sec:
Description: Draining timeout in seconds.
Format: int64
Type: integer
Type: object
Iap:
Description: IAPConfig contains configuration for IAP-enabled backends.
Properties:
Enabled:
Type: boolean
Oauthclient Credentials:
Description: OAuthClientCredentials contains credentials for a single IAP-enabled backend.
Properties:
Client ID:
Description: Direct reference to OAuth client id.
Type: string
Client Secret:
Description: Direct reference to OAuth client secret.
Type: string
Secret Name:
Description: The name of a k8s secret which stores the OAuth client id & secret.
Type: string
Required:
secretName
Type: object
Required:
enabled
oauthclientCredentials
Type: object
Security Policy:
Type: object
Session Affinity:
Description: SessionAffinityConfig contains configuration for stickyness parameters.
Properties:
Affinity Cookie Ttl Sec:
Format: int64
Type: integer
Affinity Type:
Type: string
Type: object
Timeout Sec:
Format: int64
Type: integer
Type: object
Status:
Type: object
Version: v1beta1
Versions:
Name: v1beta1
Served: true
Storage: true
Status:
Accepted Names:
Kind: BackendConfig
List Kind: BackendConfigList
Plural: backendconfigs
Singular: backendconfig
Conditions:
Last Transition Time: 2020-01-09T15:37:27Z
Message: no conflicts found
Reason: NoConflicts
Status: True
Type: NamesAccepted
Last Transition Time: <nil>
Message: the initial names have been accepted
Reason: InitialNamesAccepted
Status: True
Type: Established
Stored Versions:
v1beta1
Events: <none>

Answer 1

Create a ClusterRole and ClusterRoleBinding for service account example-sa in namespace example-namespace
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
name: backendconfig-role
rules:
- apiGroups: ["cloud.google.com"]
resources: ["backendconfigs"]
verbs: ["get", "watch", "list", "create", "delete"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
name: backendconfig-rolebinding
subjects:
- kind: ServiceAccount
name: example-sa
namespace: example-namespace
roleRef:
kind: ClusterRole
name: backendconfig-role
apiGroup: rbac.authorization.k8s.io
To check the permission is applied
kubectl auth can-i get backendconfigs --as=system:serviceaccount:example-namespace:example-sa -n example-namespace