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Running PgBouncer
This tutorial will show you how to use KubeDB to run a PgBouncer.
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/pgbouncer folder in GitHub repository kubedb/docs.
We have designed this tutorial to demonstrate a production setup of KubeDB managed PgBouncer. If you just want to try out KubeDB, you can bypass some of the safety features following the tips here.
Find Available PgBouncerVersion
When you have installed KubeDB, it has created PgBouncerVersion crd for all supported PgBouncer versions. Let’s check available PgBouncerVersion by,
$ kubectl get pgbouncerversions
NAME VERSION PGBOUNCER_IMAGE DEPRECATED AGE
1.17.0 1.17.0 ghcr.io/kubedb/pgbouncer:1.17.0 22h
1.18.0 1.18.0 ghcr.io/kubedb/pgbouncer:1.18.0 22h
Notice the DEPRECATED column. Here, true means that this PgBouncerVersion is deprecated for current KubeDB version. KubeDB will not work for deprecated PgBouncerVersion.
In this tutorial, we will use 1.18.0 PgBouncerVersion crd to create PgBouncer. To know more about what PgBouncerVersion crd is, please visit here. You can also see supported PgBouncerVersion here.
Get PostgreSQL Server ready
PgBouncer is a connection-pooling middleware for PostgreSQL. Therefore you will need to have a PostgreSQL server up and running for PgBouncer to connect to.
Luckily PostgreSQL is readily available in KubeDB as crd and can easily be deployed using this guide here.
In this tutorial, we will use a Postgres named quick-postgres in the demo namespace.
$ kubectl create -f https://github.com/kubedb/docs/raw/v2024.1.31/docs/examples/pgbouncer/quickstart/quick-postgres.yaml
postgres.kubedb.com/quick-postgres created
KubeDB creates all the necessary resources including services, secrets, and appbindings to get this server up and running. A default database postgres is created in quick-postgres. Database secret quick-postgres-auth holds this user’s username and password. Following is the yaml file for it.
$ kubectl get secrets -n demo quick-postgres-auth -o yaml
apiVersion: v1
data:
password: Um9YKkw4STs4Ujd2MzJ0aQ==
username: cG9zdGdyZXM=
kind: Secret
metadata:
creationTimestamp: "2023-10-10T11:03:47Z"
labels:
app.kubernetes.io/component: database
app.kubernetes.io/instance: quick-postgres
app.kubernetes.io/managed-by: kubedb.com
app.kubernetes.io/name: postgreses.kubedb.com
name: quick-postgres-auth
namespace: demo
resourceVersion: "5527"
uid: 7f865964-58dd-40e7-aca6-d2a3010732c3
type: kubernetes.io/basic-auth
For the purpose of this tutorial, we will need to extract the username and password from database secret quick-postgres-auth.
$ kubectl get secrets -n demo quick-postgres-auth -o jsonpath='{.data.\password}' | base64 -d
RoX*L8I;8R7v32ti⏎
$ kubectl get secrets -n demo quick-postgres-auth -o jsonpath='{.data.\username}' | base64 -d
postgres⏎
Now, to test connection with this database using the credentials obtained above, we will expose the service port associated with quick-postgres to localhost.
$ kubectl port-forward -n demo svc/quick-postgres 5432
Forwarding from 127.0.0.1:5432 -> 5432
Forwarding from [::1]:5432 -> 5432
With that done , we should now be able to connect to postgres database using username postgres, and password RoX*L8I;8R7v32ti.
$ export PGPASSWORD='RoX*L8I;8R7v32ti'
$ psql --host=localhost --port=5432 --username=postgres postgres
psql (14.9 (Ubuntu 14.9-0ubuntu0.22.04.1), server 13.2)
Type "help" for help.
postgres=#
After establishing connection successfully, we will create a table in postgres database and populate it with data.
postgres=# CREATE TABLE COMPANY( NAME TEXT NOT NULL, EMPLOYEE INT NOT NULL);
CREATE TABLE
postgres=# INSERT INTO COMPANY (name, employee) VALUES ('Apple',10);
INSERT 0 1
postgres=# INSERT INTO COMPANY (name, employee) VALUES ('Google',15);
INSERT 0 1
After data insertion, we need to verify that our data have been inserted successfully.
postgres=# SELECT * FROM company ORDER BY name;
name | employee
--------+----------
Apple | 10
Google | 15
(2 rows)
postgres=# \q
If no error occurs, quick-postgres is ready to be used by PgBouncer.
You can also use any other tool to deploy your PostgreSQL server and create a database postgres for user postgres.
Should you choose not to use KubeDB to deploy Postgres, create AppBinding(s) to point PgBouncer to your PostgreSQL server(s) where your target databases are located. Click here for detailed instructions on how to manually create AppBindings for Postgres.
Create a PgBouncer Server
KubeDB implements a PgBouncer crd to define the specifications of a PgBouncer.
Below is the PgBouncer object created in this tutorial.
apiVersion: kubedb.com/v1alpha2
kind: PgBouncer
metadata:
name: pgbouncer-server
namespace: demo
spec:
version: "1.18.0"
replicas: 1
databases:
- alias: "postgres"
databaseName: "postgres"
databaseRef:
name: "quick-postgres"
namespace: demo
connectionPool:
port: 5432
maxClientConnections: 20
reservePoolSize: 5
terminationPolicy: Delete
Here,
spec.versionis name of the PgBouncerVersion crd where the docker images are specified. In this tutorial, a PgBouncer with base image version 1.17.0 is created.spec.replicasspecifies the number of replica pgbouncer server pods to be created for the PgBouncer object.spec.databasesspecifies the databases that are going to be served via PgBouncer.spec.connectionPoolspecifies the configurations for connection pool.spec.terminationPolicyspecifies what policy to apply while deletion.
spec.databases
Databases contain three required fields and two optional fields.
spec.databases.alias: specifies an alias for the target database located in a postgres server specified by an appbinding.spec.databases.databaseName: specifies the name of the target database.spec.databases.databaseRef: specifies the name and namespace of the appBinding that contains the path to a PostgreSQL server where the target database can be found.spec.databases.username(optional): specifies the user with whom this particular database should have an exclusive connection. By default, if this field is left empty, all users will be able to use the database.spec.databases.password(optional): specifies password to authenticate the user with whom this particular database should have an exclusive connection.
spec.connectionPool
ConnectionPool is used to configure pgbouncer connection pool. All the fields here are accompanied by default values and can be left unspecified if no customization is required by the user.
spec.connectionPool.port: specifies the port on which pgbouncer should listen to connect with clients. The default is 5432.spec.connectionPool.authType: specifies how to authenticate users.spec.connectionPool.poolMode: specifies the value of pool_mode.spec.connectionPool.maxClientConnections: specifies the value of max_client_conn.spec.connectionPool.defaultPoolSize: specifies the value of default_pool_size.spec.connectionPool.minPoolSize: specifies the value of min_pool_size.spec.connectionPool.reservePoolSize: specifies the value of reserve_pool_size.spec.connectionPool.reservePoolTimeout: specifies the value of reserve_pool_timeout.spec.connectionPool.maxDbConnections: specifies the value of max_db_connections.spec.connectionPool.maxUserConnections: specifies the value of max_user_connections.
spec.terminationPolicy
terminationPolicy gives flexibility whether to nullify(reject) the delete operation of PgBouncer crd or which resources KubeDB should keep or delete when you delete PgBouncer crd. KubeDB provides following four termination policies:
- DoNotTerminate
- Delete (
Default) - WipeOut
When terminationPolicy is DoNotTerminate, KubeDB takes advantage of ValidationWebhook feature in Kubernetes 1.9.0 or later clusters to provide safety from accidental deletion of database. If admission webhook is enabled, KubeDB prevents users from deleting the database as long as the spec.terminationPolicy is set to DoNotTerminate.
Following table show what KubeDB does when you delete Postgres crd for different termination policies,
| Behavior | DoNotTerminate | Delete | WipeOut |
|---|---|---|---|
| 1. Block Delete operation | ✓ | ✗ | ✗ |
| 2. Delete StatefulSet | ✗ | ✓ | ✓ |
| 3. Delete Services | ✗ | ✓ | ✓ |
| 4. Delete PVCs | ✗ | ✓ | ✓ |
| 5. Delete Secrets | ✗ | ✗ | ✓ |
Now that we’ve been introduced to the pgBouncer crd, let’s create it,
$ kubectl create -f https://github.com/kubedb/docs/raw/v2024.1.31/docs/examples/pgbouncer/quickstart/pgbouncer-server.yaml
pgbouncer.kubedb.com/pgbouncer-server created
Connect via PgBouncer
To connect via pgBouncer we have to expose its service to localhost.
$ kubectl port-forward -n demo svc/pgbouncer-server 5432
Forwarding from 127.0.0.1:5432 -> 5432
Forwarding from [::1]:5432 -> 5432
Now, let’s connect to postgres database via PgBouncer using psql.
$ env PGPASSWORD='RoX*L8I;8R7v32ti' psql --host=localhost --port=5432 --username=postgres postgres
psql (14.9 (Ubuntu 14.9-0ubuntu0.22.04.1), server 13.2)
Type "help" for help.
postgres=# \q
If everything goes well, we’ll be connected to the postgres database and be able to execute commands. Let’s confirm if the company data we inserted in the postgres database before are available via PgBouncer:
$ env PGPASSWORD='RoX*L8I;8R7v32ti' psql --host=localhost --port=5432 --username=postgres postgres --command='SELECT * FROM company ORDER BY name;'
name | employee
--------+----------
Apple | 10
Google | 15
(2 rows)
KubeDB operator watches for PgBouncer objects using Kubernetes api. When a PgBouncer object is created, KubeDB operator will create a new StatefulSet and a Service with the matching name. KubeDB operator will also create a governing service for StatefulSet with the name kubedb, if one is not already present.
KubeDB operator sets the status.phase to Running once the connection-pooling mechanism is ready.
$ kubectl get pb -n demo pgbouncer-server -o wide
NAME VERSION STATUS AGE
pgbouncer-server 1.18.0 Ready 2h
Let’s describe PgBouncer object pgbouncer-server
$ kubectl dba describe pb -n demo pgbouncer-server
Name: pgbouncer-server
Namespace: demo
Labels: <none>
Annotations: <none>
API Version: kubedb.com/v1alpha2
Kind: PgBouncer
Metadata:
Creation Timestamp: 2023-10-11T06:28:02Z
Finalizers:
kubedb.com
Generation: 2
Managed Fields:
API Version: kubedb.com/v1alpha2
Fields Type: FieldsV1
fieldsV1:
f:metadata:
f:annotations:
.:
f:kubectl.kubernetes.io/last-applied-configuration:
f:spec:
.:
f:connectionPool:
.:
f:authType:
f:defaultPoolSize:
f:ignoreStartupParameters:
f:maxClientConnections:
f:maxDBConnections:
f:maxUserConnections:
f:minPoolSize:
f:poolMode:
f:port:
f:reservePoolSize:
f:reservePoolTimeoutSeconds:
f:statsPeriodSeconds:
f:databases:
f:healthChecker:
.:
f:failureThreshold:
f:periodSeconds:
f:timeoutSeconds:
f:replicas:
f:terminationPolicy:
f:version:
Manager: kubectl-client-side-apply
Operation: Update
Time: 2023-10-11T06:28:02Z
API Version: kubedb.com/v1alpha2
Fields Type: FieldsV1
fieldsV1:
f:metadata:
f:finalizers:
.:
v:"kubedb.com":
f:spec:
f:authSecret:
Manager: kubedb-provisioner
Operation: Update
Time: 2023-10-11T06:28:02Z
API Version: kubedb.com/v1alpha2
Fields Type: FieldsV1
fieldsV1:
f:status:
.:
f:conditions:
f:observedGeneration:
f:phase:
Manager: kubedb-provisioner
Operation: Update
Subresource: status
Time: 2023-10-11T08:43:35Z
Resource Version: 48101
UID: b5974ff8-c9e8-4308-baf0-f07bb5af9403
Spec:
Auth Secret:
Name: pgbouncer-server-auth
Auto Ops:
Connection Pool:
Auth Type: md5
Default Pool Size: 20
Ignore Startup Parameters: empty
Max Client Connections: 20
Max DB Connections: 0
Max User Connections: 0
Min Pool Size: 0
Pool Mode: session
Port: 5432
Reserve Pool Size: 5
Reserve Pool Timeout Seconds: 5
Stats Period Seconds: 60
Databases:
Alias: postgres
Database Name: postgres
Database Ref:
Name: quick-postgres
Namespace: demo
Health Checker:
Disable Write Check: true
Failure Threshold: 1
Period Seconds: 10
Timeout Seconds: 10
Pod Template:
Controller:
Metadata:
Spec:
Container Security Context:
Privileged: false
Run As Group: 70
Run As User: 70
Resources:
Limits:
Memory: 1Gi
Requests:
Cpu: 500m
Memory: 1Gi
Security Context:
Fs Group: 70
Run As Group: 70
Run As User: 70
Replicas: 1
Ssl Mode: disable
Termination Policy: Delete
Version: 1.18.0
Status:
Conditions:
Last Transition Time: 2023-10-11T06:28:02Z
Message: The KubeDB operator has started the provisioning of PgBouncer: demo/pgbouncer-server
Reason: DatabaseProvisioningStartedSuccessfully
Status: True
Type: ProvisioningStarted
Last Transition Time: 2023-10-11T08:43:35Z
Message: All replicas are ready and in Running state
Observed Generation: 2
Reason: AllReplicasReady
Status: True
Type: ReplicaReady
Last Transition Time: 2023-10-11T06:28:15Z
Message: The PgBouncer: demo/pgbouncer-server is accepting client requests.
Observed Generation: 2
Reason: DatabaseAcceptingConnectionRequest
Status: True
Type: AcceptingConnection
Last Transition Time: 2023-10-11T06:28:15Z
Message: DB is ready because of server getting Online and Running state
Observed Generation: 2
Reason: ReadinessCheckSucceeded
Status: True
Type: Ready
Last Transition Time: 2023-10-11T06:28:18Z
Message: The PgBouncer: demo/pgbouncer-server is successfully provisioned.
Observed Generation: 2
Reason: DatabaseSuccessfullyProvisioned
Status: True
Type: Provisioned
Observed Generation: 2
Phase: Ready
Events: <none>
KubeDB has created a service for the PgBouncer object.
$ kubectl get service -n demo --selector=app.kubernetes.io/name=pgbouncers.kubedb.com,app.kubernetes.io/instance=pgbouncer-server
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
pgbouncer-server ClusterIP 10.96.36.35 <none> 5432/TCP 141m
pgbouncer-server-pods ClusterIP None <none> 5432/TCP 141m
Here, Service pgbouncer-server targets random pods to carry out connection-pooling.
Cleaning up
To cleanup the Kubernetes resources created by this tutorial, run:
$ kubectl delete -n demo pg/quick-postgres
postgres.kubedb.com "quick-postgres" deleted
$ kubectl delete -n demo pb/pgbouncer-server
pgbouncer.kubedb.com "pgbouncer-server" deleted
$ kubectl delete ns demo
namespace "demo" deleted
Next Steps
- Learn about custom PgBouncerVersions.
- Monitor your PgBouncer with KubeDB using built-in Prometheus.
- Monitor your PgBouncer with KubeDB using Prometheus operator.
- Detail concepts of PgBouncer object.
- Use private Docker registry to deploy PgBouncer with KubeDB.
- Want to hack on KubeDB? Check our contribution guidelines.