k8s-create-user-for-namespace.sh

#!/bin/bash -e

NAMESPACE=$1

cat << EOF | kubectl apply -f -
---
apiVersion: v1
kind: Namespace
metadata:
  name: ${NAMESPACE}
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: ${NAMESPACE}-user
  namespace: ${NAMESPACE}
---
kind: Role
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: ${NAMESPACE}-user-full-access
  namespace: ${NAMESPACE}
rules:
- apiGroups: ["", "extensions", "apps", "autoscaling"]
  resources: ["*"]
  verbs: ["*"]
- apiGroups: ["batch"]
  resources:
  - jobs
  - cronjobs
  verbs: ["*"]
---
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: ${NAMESPACE}-user-view
  namespace: ${NAMESPACE}
subjects:
- kind: ServiceAccount
  name: ${NAMESPACE}-user
  namespace: ${NAMESPACE}
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: ${NAMESPACE}-user-full-access

---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: ${NAMESPACE}
rules:
- apiGroups:
  - admissionregistration.k8s.io
  resources:
  - validatingwebhookconfigurations
  - mutatingwebhookconfigurations
  verbs:
  - get
  - list
  - watch
- apiGroups:
  - ""
  resources:
  - namespaces
  verbs:
  - get
  - list
  - watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: ${NAMESPACE}
roleRef:
  kind: ClusterRole
  apiGroup: rbac.authorization.k8s.io
  name: ${NAMESPACE}
subjects:
- kind: ServiceAccount
  namespace: ${NAMESPACE}
  name: ${NAMESPACE}-user
EOF


TOKEN_NAME=$(kubectl -n ${NAMESPACE} describe sa ${NAMESPACE}-user | grep Tokens | awk '{print $2}')

TOKEN=$(kubectl -n ${NAMESPACE} get secret ${TOKEN_NAME} -o "jsonpath={.data.token}" | base64 --decode)
CA=$(kubectl -n ${NAMESPACE} get secret ${TOKEN_NAME} -o "jsonpath={.data['ca\.crt']}")


cat << EOF > ${NAMESPACE}-kubeconfig.yaml
apiVersion: v1
kind: Config
preferences: {}

# Define the cluster
clusters:
- cluster:
    certificate-authority-data: ${CA}
    server: https://127.0.0.1:6443
  name: my-cluster

# Define the user
users:
- name: ${NAMESPACE}-user
  user:
    as-user-extra: {}
    token: ${TOKEN}


# Define the context: linking a user to a cluster
contexts:
- context:
    cluster: my-cluster
    namespace: ${NAMESPACE}
    user: ${NAMESPACE}-user
  name: ${NAMESPACE}

# Define current context
current-context: ${NAMESPACE}
EOF

echo ${PWD}/${NAMESPACE}-kubeconfig.yaml
ls -lha ${NAMESPACE}-kubeconfig.yaml

echo kubectl --kubeconfig=${NAMESPACE}-kubeconfig.yaml get pods