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Using Custom RBAC resources
KubeDB (version 0.13.0 and higher) supports finer user control over role based access permissions provided to a PerconaXtraDB instance. This tutorial will show you how to use KubeDB to run PerconaXtraDB 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 here folder in GitHub repository kubedb/docs.
Overview
KubeDB allows users to provide custom RBAC resources, namely, ServiceAccount, Role, and RoleBinding for PerconaXtraDB. This is provided via the spec.podTemplate.spec.serviceAccountName field in PerconaXtraDB crd. If this field is left empty, the KubeDB operator will create a service account name matching PerconaXtraDB 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 PerconaXtraDB instance named quick-postges to provide the bare minimum access permissions.
Custom RBAC for PerconaXtraDB
At first, let’s create a Service Acoount in demo namespace.
$ kubectl create serviceaccount -n demo px-custom-serviceaccount
serviceaccount/px-custom-serviceaccount created
It should create a service account.
$ kubectl get serviceaccount -n demo px-custom-serviceaccount -o yaml
apiVersion: v1
kind: ServiceAccount
metadata:
creationTimestamp: "2021-03-18T04:38:59Z"
name: px-custom-serviceaccount
namespace: demo
resourceVersion: "84669"
selfLink: /api/v1/namespaces/demo/serviceaccounts/px-custom-serviceaccount
uid: 788bd6c6-3eae-4797-b6ca-5722ef64c9dc
secrets:
- name: px-custom-serviceaccount-token-jnhvd
Now, we need to create a role that has necessary access permissions for the PerconaXtraDB instance named sample-pxc.
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2023.01.17/docs/guides/percona-xtradb/custom-rbac/using-custom-rbac/examples/px-custom-role.yaml
role.rbac.authorization.k8s.io/px-custom-role created
Below is the YAML for the Role we just created.
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
name: px-custom-role
namespace: demo
rules:
- apiGroups:
- policy
resourceNames:
- perconaxtra-db
resources:
- podsecuritypolicies
verbs:
- use
This permission is required for PerconaXtraDB pods running on PSP enabled clusters.
Now create a RoleBinding to bind this Role with the already created service account.
$ kubectl create rolebinding px-custom-rolebinding --role=px-custom-role --serviceaccount=demo:px-custom-serviceaccount --namespace=demo
rolebinding.rbac.authorization.k8s.io/px-custom-rolebinding created
It should bind px-custom-role and px-custom-serviceaccount successfully.
SO, All required resources for RBAC are created.
$ kubectl get serviceaccount,role,rolebindings -n demo
NAME SECRETS AGE
serviceaccount/default 1 38m
serviceaccount/px-custom-serviceaccount 1 36m
NAME CREATED AT
role.rbac.authorization.k8s.io/px-custom-role 2021-03-18T05:13:27Z
NAME ROLE AGE
rolebinding.rbac.authorization.k8s.io/px-custom-rolebinding Role/px-custom-role 79s
Now, create a PerconaXtraDB crd specifying spec.podTemplate.spec.serviceAccountName field to px-custom-serviceaccount.
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2023.01.17/docs/guides/percona-xtradb/custom-rbac/using-custom-rbac/examples/px-custom-db.yaml
perconaxtradb.kubedb.com/sample-pxc created
Below is the YAML for the PerconaXtraDB crd we just created.
apiVersion: kubedb.com/v1alpha2
kind: PerconaXtraDB
metadata:
name: sample-pxc
namespace: demo
spec:
replicas: 3
version: "8.0.26"
storageType: Durable
podTemplate:
spec:
serviceAccountName: px-custom-serviceaccount
storage:
storageClassName: "standard"
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
terminationPolicy: WipeOut
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 sample-pxc-0 has been created.
Check that the statefulset’s pod is running
$ kubectl get pod -n demo
NAME READY STATUS RESTARTS AGE
sample-pxc-0 2/2 Running 0 84m
sample-pxc-1 2/2 Running 0 84m
sample-pxc-2 2/2 Running 0 84m
Check the PerconaXtraDB custom resource to see if the database cluster is ready:
~ $ kubectl get perconaxtradb --all-namespaces
NAMESPACE NAME VERSION STATUS AGE
demo sample-pxc 8.0.26 Ready 83m
Reusing Service Account
An existing service account can be reused in another PerconaXtraDB instance. No new access permission is required to run the new PerconaXtraDB instance.
Now, create PerconaXtraDB crd another-perconaxtradb using the existing service account name px-custom-serviceaccount in the spec.podTemplate.spec.serviceAccountName field.
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2023.01.17/docs/guides/percona-xtradb/custom-rbac/using-custom-rbac/examples/px-custom-db-2.yaml
perconaxtradb.kubedb.com/another-perconaxtradb created
Below is the YAML for the PerconaXtraDB crd we just created.
apiVersion: kubedb.com/v1alpha2
kind: PerconaXtraDB
metadata:
name: another-perconaxtradb
namespace: demo
spec:
replicas: 3
version: "8.0.26"
storageType: Durable
podTemplate:
spec:
serviceAccountName: px-custom-serviceaccount
storage:
storageClassName: "standard"
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
terminationPolicy: WipeOut
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 another-perconaxtradb has been created.
Check that the statefulset’s pod is running
$ kubectl get pod -n demo another-perconaxtradb-0
NAME READY STATUS RESTARTS AGE
another-perconaxtradb-0 2/2 Running 0 37s
Check the PerconaXtraDB custom resource to see if the database cluster is ready:
~ $ kubectl get perconaxtradb --all-namespaces
NAMESPACE NAME VERSION STATUS AGE
another-perconaxtradb sample-pxc 8.0.26 Ready 83m
Cleaning up
To cleanup the Kubernetes resources created by this tutorial, run:
$ kubectl delete perconaxtradb -n demo sample-pxc
perconaxtradb.kubedb.com "sample-pxc" deleted
$ kubectl delete perconaxtradb -n demo another-perconaxtradb
perconaxtradb.kubedb.com "another-perconaxtradb" deleted
$ kubectl delete -n demo role px-custom-role
role.rbac.authorization.k8s.io "px-custom-role" deleted
$ kubectl delete -n demo rolebinding px-custom-rolebinding
rolebinding.rbac.authorization.k8s.io "px-custom-rolebinding" deleted
$ kubectl delete sa -n demo px-custom-serviceaccount
serviceaccount "px-custom-serviceaccount" deleted
$ kubectl delete ns demo
namespace "demo" deleted