Add the capability to use RoleBindings instead of ClusterRoleBindings (…

…#841)

### Description
This PR introduces a new key to the Helm values named `useRoleBindings`
which when set to `true` creates Kubernetes RoleBindings instead of
ClusterRoleBindings

### Issues Resolved
Closes
#831

### Check List
- [x] Commits are signed per the DCO using --signoff 
- [ ] Unittest added for the new/changed functionality and all unit
tests are successful
- [x] Customer-visible features documented
- [ ] No linter warnings (`make lint`)

If CRDs are changed:
- [ ] CRD YAMLs updated (`make manifests`) and also copied into the helm
chart
- [ ] Changes to CRDs documented

Please refer to the [PR
guidelines](https://github.com/opensearch-project/opensearch-k8s-operator/blob/main/docs/developing.md#submitting-a-pr)
before submitting this pull request.

By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and
signing off your commits, please check
[here](https://github.com/opensearch-project/OpenSearch/blob/main/CONTRIBUTING.md#developer-certificate-of-origin).

---------

Signed-off-by: Nilushan Costa <nilushan@wso2.com>
Signed-off-by: Nilushan Costa <nilushancosta@gmail.com>
Co-authored-by: Sebastian Woehrl <sebastian.woehrl@maibornwolff.de>

charts/opensearch-operator/templates/opensearch-operator-manager-rolebinding.yaml

@@ -0,0 +1,27 @@
+{{- if .Values.useRoleBindings }}
+apiVersion: rbac.authorization.k8s.io/v1
+kind: RoleBinding
+metadata:
+  name: {{ include "opensearch-operator.fullname" . }}-{{ .Release.Namespace }}-manager-rolebinding
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: ClusterRole
+  name: {{ include "opensearch-operator.fullname" . }}-{{ .Release.Namespace }}-manager-role
+subjects:
+- kind: ServiceAccount
+  name: {{ include "opensearch-operator.serviceAccountName" . }}
+  namespace: {{ .Release.Namespace }}
+{{- else }}
+apiVersion: rbac.authorization.k8s.io/v1
+kind: ClusterRoleBinding
+metadata:
+  name: {{ include "opensearch-operator.fullname" . }}-{{ .Release.Namespace }}-manager-rolebinding
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: ClusterRole
+  name: {{ include "opensearch-operator.fullname" . }}-{{ .Release.Namespace }}-manager-role
+subjects:
+- kind: ServiceAccount
+  name: {{ include "opensearch-operator.serviceAccountName" . }}
+  namespace: {{ .Release.Namespace }}
+{{- end }}

charts/opensearch-operator/templates/opensearch-operator-proxy-rolebinding.yaml

@@ -0,0 +1,27 @@
+{{- if .Values.useRoleBindings }}
+apiVersion: rbac.authorization.k8s.io/v1
+kind: RoleBinding
+metadata:
+  name: {{ include "opensearch-operator.fullname" . }}-{{ .Release.Namespace }}-proxy-rolebinding
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: ClusterRole
+  name: {{ include "opensearch-operator.fullname" . }}-{{ .Release.Namespace }}-proxy-role
+subjects:
+- kind: ServiceAccount
+  name: {{ include "opensearch-operator.serviceAccountName" . }}
+  namespace: {{ .Release.Namespace }}
+{{- else }}
+apiVersion: rbac.authorization.k8s.io/v1
+kind: ClusterRoleBinding
+metadata:
+  name: {{ include "opensearch-operator.fullname" . }}-{{ .Release.Namespace }}-proxy-rolebinding
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: ClusterRole
+  name: {{ include "opensearch-operator.fullname" . }}-{{ .Release.Namespace }}-proxy-role
+subjects:
+- kind: ServiceAccount
+  name: {{ include "opensearch-operator.serviceAccountName" . }}
+  namespace: {{ .Release.Namespace }}
+{{- end }}

charts/opensearch-operator/values.yaml

@@ -115,3 +115,9 @@ kubeRbacProxy:
   image:
     repository: "gcr.io/kubebuilder/kube-rbac-proxy"
     tag: "v0.15.0"
+
+## If this is set to true, RoleBindings will be used instead of ClusterRoleBindings, inorder to restrict ClusterRoles
+## to the namespace where the operator and OpenSearch cluster are in. In that case, specify the namespace where they
+## are in in manager.watchNamespace field.
+## If false, ClusterRoleBindings will be used
+useRoleBindings: false