New to KubeDB? Please start here.

Using Custom RBAC resources

KubeDB (version 0.13.0 and higher) supports finer user control over role based access permissions provided to a Redis instance. This tutorial will show you how to use KubeDB to run Redis instance with custom RBAC resources.

Before You Begin

At first, you need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using kind.

Now, install KubeDB cli on your workstation and KubeDB operator in your cluster following the steps here.

To keep things isolated, this tutorial uses a separate namespace called demo throughout this tutorial.

$ kubectl create ns demo
namespace/demo created

Note: YAML files used in this tutorial are stored in docs/examples/redis folder in GitHub repository kubedb/docs.

Overview

KubeDB allows users to provide custom RBAC resources, namely, ServiceAccount, Role, and RoleBinding for Redis. This is provided via the spec.podTemplate.spec.serviceAccountName field in Redis crd. If this field is left empty, the KubeDB operator will create a service account name matching Redis crd name. Role and RoleBinding that provide necessary access permissions will also be generated automatically for this service account.

If a service account name is given, but there’s no existing service account by that name, the KubeDB operator will create one, and Role and RoleBinding that provide necessary access permissions will also be generated for this service account.

If a service account name is given, and there’s an existing service account by that name, the KubeDB operator will use that existing service account. Since this service account is not managed by KubeDB, users are responsible for providing necessary access permissions manually.

This guide will show you how to create custom Service Account, Role, and RoleBinding for a Redis instance named quick-redis to provide the bare minimum access permissions.

Custom RBAC for Redis

At first, let’s create a Service Acoount in demo namespace.

$ kubectl create serviceaccount -n demo my-custom-serviceaccount
serviceaccount/my-custom-serviceaccount created

It should create a service account.

$ kubectl get serviceaccount -n demo my-custom-serviceaccount -o yaml

apiVersion: v1
kind: ServiceAccount
metadata:
  creationTimestamp: "2023-02-06T10:19:00Z"
  name: my-custom-serviceaccount
  namespace: demo
  resourceVersion: "683509"
  uid: 186702c3-6d84-4ba9-b349-063c4e681622
secrets:
  - name: my-custom-serviceaccount-token-vpr84

Now, we need to create a role that has necessary access permissions for the Redis instance named quick-redis.

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2023.11.2/docs/examples/redis/custom-rbac/rd-custom-role.yaml
role.rbac.authorization.k8s.io/my-custom-role created

Below is the YAML for the Role we just created.

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: my-custom-role
  namespace: demo
rules:
- apiGroups:
  - policy
  resourceNames:
  - redis-db
  resources:
  - podsecuritypolicies
  verbs:
  - use

This permission is required for Redis pods running on PSP enabled clusters.

Now create a RoleBinding to bind this Role with the already created service account.

$ kubectl create rolebinding my-custom-rolebinding --role=my-custom-role --serviceaccount=demo:my-custom-serviceaccount --namespace=demo
rolebinding.rbac.authorization.k8s.io/my-custom-rolebinding created

It should bind my-custom-role and my-custom-serviceaccount successfully.

$ kubectl get rolebinding -n demo my-custom-rolebinding -o yaml

apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  creationTimestamp: "2023-02-06T09:46:26Z"
  name: my-custom-rolebinding
  namespace: demo
  resourceVersion: "680621"
  uid: 6f74cce7-bb20-4584-bdc1-bdfb3598604f
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: my-custom-role
subjects:
  - kind: ServiceAccount
    name: my-custom-serviceaccount
    namespace: demo

Now, create a Redis crd specifying spec.podTemplate.spec.serviceAccountName field to my-custom-serviceaccount.

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2023.11.2/docs/examples/redis/custom-rbac/rd-custom-db.yaml
redis.kubedb.com/quick-redis created

Below is the YAML for the Redis crd we just created.

apiVersion: kubedb.com/v1alpha2
kind: Redis
metadata:
  name: quick-redis
  namespace: demo
spec:
  version: 6.2.5
  storageType: Durable
  storage:
    storageClassName: "standard"
    accessModes:
    - ReadWriteOnce
    resources:
      requests:
        storage: 1Gi
  terminationPolicy: DoNotTerminate

Now, wait a few minutes. the KubeDB operator will create necessary PVC, statefulset, services, secret etc. If everything goes well, we should see that a pod with the name quick-redis-0 has been created.

Check that the statefulset’s pod is running

$ kubectl get pod -n demo quick-redis-0
NAME            READY   STATUS    RESTARTS   AGE
quick-redis-0   1/1     Running   0          61s

Check if database is in Ready state

$ kubectl get redis -n demo
NAME          VERSION   STATUS   AGE
quick-redis   6.2.5     Ready    117s

Reusing Service Account

An existing service account can be reused in another Redis instance. No new access permission is required to run the new Redis instance.

Now, create Redis crd minute-redis using the existing service account name my-custom-serviceaccount in the spec.podTemplate.spec.serviceAccountName field.

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2023.11.2/docs/examples/redis/custom-rbac/rd-custom-db-two.yaml
redis.kubedb.com/quick-redis created

Below is the YAML for the Redis crd we just created.

apiVersion: kubedb.com/v1alpha2
kind: Redis
metadata:
  name: minute-redis
  namespace: demo
spec:
  version: 6.2.5
  podTemplate:
    spec:
      serviceAccountName: my-custom-serviceaccount
  storageType: Durable
  storage:
    storageClassName: "standard"
    accessModes:
    - ReadWriteOnce
    resources:
      requests:
        storage: 1Gi
  terminationPolicy: DoNotTerminate

Now, wait a few minutes. the KubeDB operator will create necessary PVC, statefulset, services, secret etc. If everything goes well, we should see that a pod with the name minute-redis-0 has been created.

Check that the statefulset’s pod is running

$ kubectl get pod -n demo minute-redis-0
NAME                READY     STATUS    RESTARTS   AGE
minute-redis-0   1/1       Running   0          14m

Check if database is in Ready state

$ kubectl get redis -n demo
NAME           VERSION   STATUS   AGE
minute-redis   6.2.5     Ready    76s
quick-redis    6.2.5     Ready    4m26s

Cleaning up

To clean up the Kubernetes resources created by this tutorial, run:

$ kubectl patch -n demo rd/quick-redis -p '{"spec":{"terminationPolicy":"WipeOut"}}' --type="merge"
redis.kubedb.com/quick-redis patched

$ kubectl delete -n demo rd/quick-redis
redis.kubedb.com "quick-redis" deleted

$ kubectl patch -n demo rd/minute-redis -p '{"spec":{"terminationPolicy":"WipeOut"}}' --type="merge"
redis.kubedb.com/minute-redis patched

$ kubectl delete -n demo rd/minute-redis
redis.kubedb.com "minute-redis" deleted

$ kubectl delete -n demo role my-custom-role
role.rbac.authorization.k8s.io "my-custom-role" deleted

$ kubectl delete -n demo rolebinding my-custom-rolebinding
rolebinding.rbac.authorization.k8s.io "my-custom-rolebinding" deleted

$ kubectl delete sa -n demo my-custom-serviceaccount
serviceaccount "my-custom-serviceaccount" deleted

$ kubectl delete ns demo
namespace "demo" deleted

If you would like to uninstall the KubeDB operator, please follow the steps here.

Next Steps

• Quickstart Redis with KubeDB Operator.
• Monitor your Redis instance with KubeDB using out-of-the-box Prometheus operator.
• Monitor your Redis instance with KubeDB using out-of-the-box builtin-Prometheus.
• Use private Docker registry to deploy Redis with KubeDB.
• Use kubedb cli to manage databases like kubectl for Kubernetes.
• Detail concepts of Redis object.
• Want to hack on KubeDB? Check our contribution guidelines.