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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 Pgpool instance. This tutorial will show you how to use KubeDB to run Pgpool 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/pgpool folder in GitHub repository kubedb/docs.
Overview
KubeDB allows users to provide custom RBAC resources, namely, ServiceAccount, Role, and RoleBinding for Pgpool. This is provided via the spec.podTemplate.spec.serviceAccountName field in Pgpool crd. If this field is left empty, the KubeDB operator will use the default service account. Role and RoleBinding that provide necessary access permissions will also be generated automatically 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 Pgpool instance named pgpool to provide the bare minimum access permissions.
Custom RBAC for Pgpool
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: "2024-08-01T04:55:42Z"
name: my-custom-serviceaccount
namespace: demo
resourceVersion: "269793"
uid: 21a51f82-84b8-47ee-ab80-4404778bc5ee
Now, we need to create a role that has necessary access permissions for the Pgpool instance named pgpool.
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.8.21/docs/examples/pgpool/custom-rbac/mg-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:
- pgpool
resources:
- podsecuritypolicies
verbs:
- use
This permission is required for Pgpool 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: "2024-08-01T04:59:20Z"
name: my-custom-rolebinding
namespace: demo
resourceVersion: "270018"
uid: bd6b4fe3-5b2e-4cc4-a51e-2eba0a3af5e3
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: Role
name: my-custom-role
subjects:
- kind: ServiceAccount
name: my-custom-serviceaccount
namespace: demo
Now, create a Pgpool crd specifying spec.podTemplate.spec.serviceAccountName field to my-custom-serviceaccount.
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.8.21/docs/examples/pgpool/custom-rbac/pp-custom.yaml
pgpool.kubedb.com/pgpool created
Below is the YAML for the Pgpool crd we just created.
apiVersion: kubedb.com/v1alpha2
kind: Pgpool
metadata:
name: pgpool
namespace: demo
spec:
version: "4.5.0"
replicas: 1
postgresRef:
name: ha-postgres
namespace: demo
podTemplate:
spec:
serviceAccountName: my-custom-serviceaccount
deletionPolicy: WipeOut
Now, wait a few minutes. the KubeDB operator will create necessary petset, services, secret etc. If everything goes well, we should see that a pod with the name pgpool-0 has been created.
Check that the petset’s pod is running
$ kubectl get pod -n demo pgpool-0
NAME READY STATUS RESTARTS AGE
pgpool-0 1/1 Running 0 50s
Check the pod’s log to see if the pgpool is ready
$ kubectl logs -f -n demo pgpool-0
Configuring Pgpool-II...
Custom pgpool.conf file detected. Use custom configuration files.
Generating pool_passwd...
Generating pcp.conf...
Custom pool_hba.conf file detected. Use custom pool_hba.conf.
Starting Pgpool-II...
2024-08-01 05:03:29.081: main pid 61: LOG: Backend status file /tmp/pgpool_status does not exist
2024-08-01 05:03:29.081: main pid 61: LOG: health_check_stats_shared_memory_size: requested size: 12288
2024-08-01 05:03:29.081: main pid 61: LOG: memory cache initialized
2024-08-01 05:03:29.081: main pid 61: DETAIL: memcache blocks :64
2024-08-01 05:03:29.081: main pid 61: LOG: allocating (135894880) bytes of shared memory segment
2024-08-01 05:03:29.081: main pid 61: LOG: allocating shared memory segment of size: 135894880
2024-08-01 05:03:30.129: main pid 61: LOG: health_check_stats_shared_memory_size: requested size: 12288
2024-08-01 05:03:30.129: main pid 61: LOG: health_check_stats_shared_memory_size: requested size: 12288
2024-08-01 05:03:30.129: main pid 61: LOG: memory cache initialized
2024-08-01 05:03:30.129: main pid 61: DETAIL: memcache blocks :64
2024-08-01 05:03:30.130: main pid 61: LOG: pool_discard_oid_maps: discarded memqcache oid maps
2024-08-01 05:03:30.150: main pid 61: LOG: create socket files[0]: /tmp/.s.PGSQL.9999
2024-08-01 05:03:30.150: main pid 61: LOG: listen address[0]: *
2024-08-01 05:03:30.150: main pid 61: LOG: Setting up socket for 0.0.0.0:9999
2024-08-01 05:03:30.150: main pid 61: LOG: Setting up socket for :::9999
2024-08-01 05:03:30.151: main pid 61: LOG: find_primary_node_repeatedly: waiting for finding a primary node
2024-08-01 05:03:30.151: main pid 61: LOG: create socket files[0]: /var/run/pgpool/.s.PGSQL.9595
2024-08-01 05:03:30.151: main pid 61: LOG: listen address[0]: *
2024-08-01 05:03:30.151: main pid 61: LOG: Setting up socket for 0.0.0.0:9595
2024-08-01 05:03:30.151: main pid 61: LOG: Setting up socket for :::9595
2024-08-01 05:03:30.151: pcp_main pid 68: LOG: PCP process: 68 started
2024-08-01 05:03:30.152: sr_check_worker pid 69: LOG: process started
2024-08-01 05:03:30.152: health_check pid 70: LOG: process started
2024-08-01 05:03:30.152: health_check pid 71: LOG: process started
2024-08-01 05:03:30.153: main pid 61: LOG: pgpool-II successfully started. version 4.5.0 (hotooriboshi)
Once we see pgpool-II successfully started in the log, the pgpool is ready.
Also, if we want to verify that the pod is actually using our custom service account we can just describe the pod and see the Service Accouunt Name,
$ kubectl describe pp -n demo pgpool
Name: pgpool
Namespace: demo
Labels: <none>
Annotations: <none>
API Version: kubedb.com/v1alpha2
Kind: Pgpool
Metadata:
Creation Timestamp: 2024-08-01T05:03:26Z
Finalizers:
kubedb.com
Generation: 2
Resource Version: 271249
UID: 53b75d96-4e5c-45ec-bccd-6c2ca5a363ec
Spec:
Auth Secret:
Name: pgpool-auth
Client Auth Mode: md5
Deletion Policy: WipeOut
Health Checker:
Failure Threshold: 1
Period Seconds: 10
Timeout Seconds: 10
Pod Template:
Controller:
Metadata:
Spec:
Containers:
Name: pgpool
Resources:
Limits:
Memory: 1Gi
Requests:
Cpu: 500m
Memory: 1Gi
Security Context:
Allow Privilege Escalation: false
Capabilities:
Drop:
ALL
Run As Group: 70
Run As Non Root: true
Run As User: 70
Seccomp Profile:
Type: RuntimeDefault
Pod Placement Policy:
Name: default
Security Context:
Fs Group: 70
Service Account Name: my-custom-serviceaccount
Postgres Ref:
Name: ha-postgres
Namespace: demo
Replicas: 1
Ssl Mode: disable
Version: 4.5.0
Status:
Conditions:
Last Transition Time: 2024-08-01T05:03:27Z
Message: The KubeDB operator has started the provisioning of Pgpool: demo/pgpool
Observed Generation: 1
Reason: DatabaseProvisioningStartedSuccessfully
Status: True
Type: ProvisioningStarted
Last Transition Time: 2024-08-01T05:17:50Z
Message: All replicas are ready for Pgpool demo/pgpool
Observed Generation: 2
Reason: AllReplicasReady
Status: True
Type: ReplicaReady
Last Transition Time: 2024-08-01T05:03:39Z
Message: pgpool demo/pgpool is accepting connection
Observed Generation: 2
Reason: AcceptingConnection
Status: True
Type: AcceptingConnection
Last Transition Time: 2024-08-01T05:03:39Z
Message: pgpool demo/pgpool is ready
Observed Generation: 2
Reason: AllReplicasReady
Status: True
Type: Ready
Last Transition Time: 2024-08-01T05:03:39Z
Message: The Pgpool: demo/pgpool is successfully provisioned.
Observed Generation: 2
Reason: DatabaseSuccessfullyProvisioned
Status: True
Type: Provisioned
Phase: Ready
Events: <none>
Reusing Service Account
An existing service account can be reused in another Pgpool instance. No new access permission is required to run the new Pgpool instance.
Now, create Pgpool crd pgpool-new 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/v2024.8.21/docs/examples/pgpool/custom-rbac/pgpool-new.yaml
pgpool.kubedb.com/quick-pgpool created
Below is the YAML for the Pgpool crd we just created.
apiVersion: kubedb.com/v1alpha2
kind: Pgpool
metadata:
name: pgpool-new
namespace: demo
spec:
version: "4.5.0"
replicas: 1
postgresRef:
name: ha-postgres
namespace: demo
podTemplate:
spec:
serviceAccountName: my-custom-serviceaccount
deletionPolicy: WipeOut
Now, wait a few minutes. the KubeDB operator will create necessary petset, services, secret etc. If everything goes well, we should see that a pod with the name pgpool-new-0 has been created.
Check that the petset’s pod is running
$ kubectl get pod -n demo pgpool-new-0
NAME READY STATUS RESTARTS AGE
pgpool-new-0 1/1 Running 0 55s
Check the pod’s log to see if the database is ready
$ kubectl logs -f -n demo pgpool-new-0
Configuring Pgpool-II...
Custom pgpool.conf file detected. Use custom configuration files.
Generating pool_passwd...
Generating pcp.conf...
Custom pool_hba.conf file detected. Use custom pool_hba.conf.
Starting Pgpool-II...
2024-08-01 05:05:34.353: main pid 60: LOG: Backend status file /tmp/pgpool_status does not exist
2024-08-01 05:05:34.353: main pid 60: LOG: health_check_stats_shared_memory_size: requested size: 12288
2024-08-01 05:05:34.353: main pid 60: LOG: memory cache initialized
2024-08-01 05:05:34.353: main pid 60: DETAIL: memcache blocks :64
2024-08-01 05:05:34.353: main pid 60: LOG: allocating (135894880) bytes of shared memory segment
2024-08-01 05:05:34.353: main pid 60: LOG: allocating shared memory segment of size: 135894880
2024-08-01 05:05:34.555: main pid 60: LOG: health_check_stats_shared_memory_size: requested size: 12288
2024-08-01 05:05:34.555: main pid 60: LOG: health_check_stats_shared_memory_size: requested size: 12288
2024-08-01 05:05:34.555: main pid 60: LOG: memory cache initialized
2024-08-01 05:05:34.555: main pid 60: DETAIL: memcache blocks :64
2024-08-01 05:05:34.556: main pid 60: LOG: pool_discard_oid_maps: discarded memqcache oid maps
2024-08-01 05:05:34.567: main pid 60: LOG: create socket files[0]: /tmp/.s.PGSQL.9999
2024-08-01 05:05:34.567: main pid 60: LOG: listen address[0]: *
2024-08-01 05:05:34.567: main pid 60: LOG: Setting up socket for 0.0.0.0:9999
2024-08-01 05:05:34.568: main pid 60: LOG: Setting up socket for :::9999
2024-08-01 05:05:34.568: main pid 60: LOG: find_primary_node_repeatedly: waiting for finding a primary node
2024-08-01 05:05:34.568: main pid 60: LOG: create socket files[0]: /var/run/pgpool/.s.PGSQL.9595
2024-08-01 05:05:34.569: main pid 60: LOG: listen address[0]: *
2024-08-01 05:05:34.569: main pid 60: LOG: Setting up socket for 0.0.0.0:9595
2024-08-01 05:05:34.569: main pid 60: LOG: Setting up socket for :::9595
2024-08-01 05:05:34.569: sr_check_worker pid 68: LOG: process started
2024-08-01 05:05:34.570: health_check pid 69: LOG: process started
2024-08-01 05:05:34.570: health_check pid 70: LOG: process started
2024-08-01 05:05:34.570: pcp_main pid 67: LOG: PCP process: 67 started
2024-08-01 05:05:34.570: main pid 60: LOG: pgpool-II successfully started. version 4.5.0 (hotooriboshi)
pgpool-II successfully started in the log signifies that the pgpool is running successfully.
Also, if we want to verify that the pod is actually using our custom service account we can just describe the pod and see the Service Accouunt Name,
$ kubectl describe pp -n demo pgpool-new
Name: pgpool-new
Namespace: demo
Labels: <none>
Annotations: <none>
API Version: kubedb.com/v1alpha2
Kind: Pgpool
Metadata:
Creation Timestamp: 2024-08-01T05:05:32Z
Finalizers:
kubedb.com
Generation: 2
Resource Version: 271244
UID: e985525a-9479-4364-9c8f-192c476fd2dc
Spec:
Auth Secret:
Name: pgpool-new-auth
Client Auth Mode: md5
Deletion Policy: WipeOut
Health Checker:
Failure Threshold: 1
Period Seconds: 10
Timeout Seconds: 10
Pod Template:
Controller:
Metadata:
Spec:
Containers:
Name: pgpool
Resources:
Limits:
Memory: 1Gi
Requests:
Cpu: 500m
Memory: 1Gi
Security Context:
Allow Privilege Escalation: false
Capabilities:
Drop:
ALL
Run As Group: 70
Run As Non Root: true
Run As User: 70
Seccomp Profile:
Type: RuntimeDefault
Pod Placement Policy:
Name: default
Security Context:
Fs Group: 70
Service Account Name: my-custom-serviceaccount
Postgres Ref:
Name: ha-postgres
Namespace: demo
Replicas: 1
Ssl Mode: disable
Version: 4.5.0
Status:
Conditions:
Last Transition Time: 2024-08-01T05:05:33Z
Message: The KubeDB operator has started the provisioning of Pgpool: demo/pgpool-new
Observed Generation: 2
Reason: DatabaseProvisioningStartedSuccessfully
Status: True
Type: ProvisioningStarted
Last Transition Time: 2024-08-01T05:17:49Z
Message: All replicas are ready for Pgpool demo/pgpool-new
Observed Generation: 2
Reason: AllReplicasReady
Status: True
Type: ReplicaReady
Last Transition Time: 2024-08-01T05:05:45Z
Message: pgpool demo/pgpool-new is accepting connection
Observed Generation: 2
Reason: AcceptingConnection
Status: True
Type: AcceptingConnection
Last Transition Time: 2024-08-01T05:05:45Z
Message: pgpool demo/pgpool-new is ready
Observed Generation: 2
Reason: AllReplicasReady
Status: True
Type: Ready
Last Transition Time: 2024-08-01T05:05:45Z
Message: The Pgpool: demo/pgpool-new is successfully provisioned.
Observed Generation: 2
Reason: DatabaseSuccessfullyProvisioned
Status: True
Type: Provisioned
Phase: Ready
Events: <none>
Cleaning up
To clean up the Kubernetes resources created by this tutorial, run:
kubectl delete -n demo pp/pgpool
kubectl delete -n demo pp/pgpool-new
kubectl delete -n demo role my-custom-role
kubectl delete -n demo rolebinding my-custom-rolebinding
kubectl delete sa -n demo my-custom-serviceaccount
kubectl delete -n demo pg/ha-postgres
kubectl delete ns demo
If you would like to uninstall the KubeDB operator, please follow the steps here.
Next Steps
- Quickstart Pgpool with KubeDB Operator.
- Monitor your Pgpool instance with KubeDB using out-of-the-box Prometheus operator.
- Monitor your Pgpool instance with KubeDB using out-of-the-box builtin-Prometheus.
- Detail concepts of Pgpool object.
- Want to hack on KubeDB? Check our contribution guidelines.