Manage scaling of Statefulsets using Kubernetes API

Question

I want scale up my statefulset and want to initiate this scale up from inside the pod(container) using the Kubernetes API(http request) to the kubernetes rest server.
I tried scaling up statefulset pods using

PUT /apis/apps/v1/namespaces/{namespace}/statefulsets/{name}/scale

but it didn't work for me.

Even tried fetching the scale data of specified statefulset using

"GET /apis/apps/v1/namespaces/{namespace}/statefulsets/{name}/scale"

REQUEST : curl -s -k -H "Authorization: Bearer $TOKEN" -X GET https://kubernetes.default.svc:443/apis/apps/v1/namespaces/$Namespace/$Kind/$PodNamePrefix/scale

Gives an error :

"message": "statefulsets.apps "app-4x" is forbidden: User "system:serviceaccount::default" cannot get resource "statefulsets/scale" in API group "apps" in the namespace ""","reason": "Forbidden",
Reference : https://v1-14.docs.kubernetes.io/docs/reference/generated/kubernetes-api/v1.14/

Can somebody help me with this?

error mesaage state that service account do not have permission to view the statefulsets. ask your kubernetes administrator to assign permission to this service account — Dashrath Mundkar, Aug 21 '20 at 08:49
@DashrathMundkar yes there was some permission issue regarding the service account. Thanks for the help. — himanshu, Aug 22 '20 at 10:57

score 8 · Accepted Answer · edited Aug 21 '20 at 10:08

You need to define RBAC using Role and RoleBinding to authorize the service account to perform the required operations

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  namespace: default
  name: ss-role
rules:
- apiGroups: ["apps"]
  resources: ["statefulsets/scale" ]
  verbs: ["get", "list", "create"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  namespace: default
  name: ss-rolebinding
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: ss-role
subjects:
- kind: ServiceAccount
  name: default
  namespace: default

Above Role and RoleBinding is based on the assumption that you are using default service account of default namespace to scale statefulsets in default namespace.

Manage scaling of Statefulsets using Kubernetes API

1 Answers1