Overview
KubeDB is the Kubernetes Native Database Management Solution which simplifies and automates routine database tasks such as Provisioning, Monitoring, Upgrading, Patching, Scaling, Volume Expansion, Backup, Recovery, Failure detection, and Repair for various popular databases on private and public clouds. The databases supported by KubeDB include MongoDB, Elasticsearch, MySQL, MariaDB, Redis, PostgreSQL, FerretDB, SingleStore, Percona XtraDB, and Memcached. Additionally, KubeDB also supports ProxySQL, PgBouncer, Pgpool, ZooKeeper and the streaming platform Kafka, RabbitMQ. You can find the guides to all the supported databases in KubeDB . In this tutorial we will show Horizontal scaling of PostgreSQL cluster in Amazon Elastic Kubernetes Service (Amazon EKS). We will cover the following steps:
- Install KubeDB
- Deploy PostgreSQL Cluster
- Read/Write Sample Data
- Horizontal Scaling of PostgreSQL Cluster
Get Cluster ID
We need the cluster ID to get the KubeDB License. To get cluster ID, we can run the following command:
$ kubectl get ns kube-system -o jsonpath='{.metadata.uid}'
8e336615-0dbb-4ae8-b72f-2e7ec34c399d
Get License
Go to Appscode License Server to get the license.txt file. For this tutorial we will use KubeDB.
Install KubeDB
We will use helm to install KubeDB. Please install helm here
if it is not already installed.
Now, let’s install KubeDB.
$ helm install kubedb oci://ghcr.io/appscode-charts/kubedb \
--version v2024.6.4 \
--namespace kubedb --create-namespace \
--set-file global.license=/path/to/the/license.txt \
--wait --burst-limit=10000 --debug
$ helm search repo appscode/kubedb
NAME CHART VERSION APP VERSION DESCRIPTION
appscode/kubedb v2024.6.4 v2024.6.4 KubeDB by AppsCode - Production ready databases...
appscode/kubedb-autoscaler v0.31.0 v0.31.0 KubeDB Autoscaler by AppsCode - Autoscale KubeD...
appscode/kubedb-catalog v2024.6.4 v2024.6.4 KubeDB Catalog by AppsCode - Catalog for databa...
appscode/kubedb-community v0.24.2 v0.24.2 KubeDB Community by AppsCode - Community featur...
appscode/kubedb-crd-manager v0.1.0 v0.1.0 KubeDB CRD Manager by AppsCode
appscode/kubedb-crds v2024.6.4 v2024.6.4 KubeDB Custom Resource Definitions
appscode/kubedb-dashboard v0.22.0 v0.22.0 KubeDB Dashboard by AppsCode
appscode/kubedb-enterprise v0.11.2 v0.11.2 KubeDB Enterprise by AppsCode - Enterprise feat...
appscode/kubedb-grafana-dashboards v2024.6.4 v2024.6.4 A Helm chart for kubedb-grafana-dashboards by A...
appscode/kubedb-kubestash-catalog v2024.6.4 v2024.6.4 KubeStash Catalog by AppsCode - Catalog of Kube...
appscode/kubedb-metrics v2024.6.4 v2024.6.4 KubeDB State Metrics
appscode/kubedb-one v2023.12.28 v2023.12.28 KubeDB and Stash by AppsCode - Production ready...
appscode/kubedb-ops-manager v0.33.0 v0.33.0 KubeDB Ops Manager by AppsCode - Enterprise fea...
appscode/kubedb-opscenter v2024.6.4 v2024.6.4 KubeDB Opscenter by AppsCode
appscode/kubedb-provider-aws v2024.6.4 v0.8.0 A Helm chart for KubeDB AWS Provider for Crossp...
appscode/kubedb-provider-azure v2024.6.4 v0.8.0 A Helm chart for KubeDB Azure Provider for Cros...
appscode/kubedb-provider-gcp v2024.6.4 v0.8.0 A Helm chart for KubeDB GCP Provider for Crossp...
appscode/kubedb-provisioner v0.46.0 v0.46.0 KubeDB Provisioner by AppsCode - Community feat...
appscode/kubedb-schema-manager v0.22.0 v0.22.0 KubeDB Schema Manager by AppsCode
appscode/kubedb-ui v2024.6.18 0.6.9 A Helm chart for Kubernetes
appscode/kubedb-ui-presets v2024.6.18 v2024.6.18 KubeDB UI Presets
appscode/kubedb-ui-server v2021.12.21 v2021.12.21 A Helm chart for kubedb-ui-server by AppsCode
appscode/kubedb-webhook-server v0.22.0 v0.22.0 KubeDB Webhook Server by AppsCode
Let’s verify the installation:
$ kubectl get pods --all-namespaces -l "app.kubernetes.io/instance=kubedb"
NAMESPACE NAME READY STATUS RESTARTS AGE
kubedb kubedb-kubedb-autoscaler-645b49bc48-w6k9h 1/1 Running 0 3m25s
kubedb kubedb-kubedb-ops-manager-5b67db5b95-gzzlm 1/1 Running 0 3m26s
kubedb kubedb-kubedb-provisioner-bb69f7dbf-nvtjh 1/1 Running 0 3m26s
kubedb kubedb-kubedb-webhook-server-85766fd79d-gkd6x 1/1 Running 0 3m26s
kubedb kubedb-petset-operator-54877fd499-527zm 1/1 Running 0 3m26s
kubedb kubedb-petset-webhook-server-7d5589d84-crnm4 2/2 Running 0 3m25s
kubedb kubedb-sidekick-5d9947bd9-qnchg 1/1 Running 0 3m26s
We can list the CRD Groups that have been registered by the operator by running the following command:
$ kubectl get crd -l app.kubernetes.io/name=kubedb
NAME CREATED AT
clickhouseversions.catalog.kubedb.com 2024-07-05T12:36:49Z
connectclusters.kafka.kubedb.com 2024-07-05T12:37:32Z
connectors.kafka.kubedb.com 2024-07-05T12:37:32Z
druidversions.catalog.kubedb.com 2024-07-05T12:36:49Z
elasticsearchautoscalers.autoscaling.kubedb.com 2024-07-05T12:37:29Z
elasticsearchdashboards.elasticsearch.kubedb.com 2024-07-05T12:37:29Z
elasticsearches.kubedb.com 2024-07-05T12:37:29Z
elasticsearchopsrequests.ops.kubedb.com 2024-07-05T12:37:29Z
elasticsearchversions.catalog.kubedb.com 2024-07-05T12:36:49Z
etcdversions.catalog.kubedb.com 2024-07-05T12:36:49Z
ferretdbversions.catalog.kubedb.com 2024-07-05T12:36:49Z
kafkaautoscalers.autoscaling.kubedb.com 2024-07-05T12:37:32Z
kafkaconnectorversions.catalog.kubedb.com 2024-07-05T12:36:49Z
kafkaopsrequests.ops.kubedb.com 2024-07-05T12:37:32Z
kafkas.kubedb.com 2024-07-05T12:37:32Z
kafkaversions.catalog.kubedb.com 2024-07-05T12:36:49Z
mariadbarchivers.archiver.kubedb.com 2024-07-05T12:37:35Z
mariadbautoscalers.autoscaling.kubedb.com 2024-07-05T12:37:35Z
mariadbdatabases.schema.kubedb.com 2024-07-05T12:37:35Z
mariadbopsrequests.ops.kubedb.com 2024-07-05T12:37:35Z
mariadbs.kubedb.com 2024-07-05T12:37:35Z
mariadbversions.catalog.kubedb.com 2024-07-05T12:36:49Z
memcachedversions.catalog.kubedb.com 2024-07-05T12:36:49Z
mongodbarchivers.archiver.kubedb.com 2024-07-05T12:37:39Z
mongodbautoscalers.autoscaling.kubedb.com 2024-07-05T12:37:39Z
mongodbdatabases.schema.kubedb.com 2024-07-05T12:37:39Z
mongodbopsrequests.ops.kubedb.com 2024-07-05T12:37:39Z
mongodbs.kubedb.com 2024-07-05T12:37:39Z
mongodbversions.catalog.kubedb.com 2024-07-05T12:36:49Z
mssqlserverversions.catalog.kubedb.com 2024-07-05T12:36:49Z
mysqlarchivers.archiver.kubedb.com 2024-07-05T12:37:43Z
mysqlautoscalers.autoscaling.kubedb.com 2024-07-05T12:37:42Z
mysqldatabases.schema.kubedb.com 2024-07-05T12:37:43Z
mysqlopsrequests.ops.kubedb.com 2024-07-05T12:37:42Z
mysqls.kubedb.com 2024-07-05T12:37:42Z
mysqlversions.catalog.kubedb.com 2024-07-05T12:36:49Z
perconaxtradbversions.catalog.kubedb.com 2024-07-05T12:36:49Z
pgbouncerversions.catalog.kubedb.com 2024-07-05T12:36:49Z
pgpoolversions.catalog.kubedb.com 2024-07-05T12:36:49Z
postgresarchivers.archiver.kubedb.com 2024-07-05T12:37:46Z
postgresautoscalers.autoscaling.kubedb.com 2024-07-05T12:37:46Z
postgresdatabases.schema.kubedb.com 2024-07-05T12:37:46Z
postgreses.kubedb.com 2024-07-05T12:37:46Z
postgresopsrequests.ops.kubedb.com 2024-07-05T12:37:46Z
postgresversions.catalog.kubedb.com 2024-07-05T12:36:49Z
proxysqlversions.catalog.kubedb.com 2024-07-05T12:36:49Z
publishers.postgres.kubedb.com 2024-07-05T12:37:46Z
rabbitmqversions.catalog.kubedb.com 2024-07-05T12:36:49Z
redisautoscalers.autoscaling.kubedb.com 2024-07-05T12:37:49Z
redises.kubedb.com 2024-07-05T12:37:49Z
redisopsrequests.ops.kubedb.com 2024-07-05T12:37:49Z
redissentinelautoscalers.autoscaling.kubedb.com 2024-07-05T12:37:49Z
redissentinelopsrequests.ops.kubedb.com 2024-07-05T12:37:49Z
redissentinels.kubedb.com 2024-07-05T12:37:49Z
redisversions.catalog.kubedb.com 2024-07-05T12:36:49Z
schemaregistries.kafka.kubedb.com 2024-07-05T12:37:32Z
schemaregistryversions.catalog.kubedb.com 2024-07-05T12:36:49Z
singlestoreversions.catalog.kubedb.com 2024-07-05T12:36:49Z
solrversions.catalog.kubedb.com 2024-07-05T12:36:49Z
subscribers.postgres.kubedb.com 2024-07-05T12:37:46Z
zookeeperversions.catalog.kubedb.com 2024-07-05T12:36:49Z
Deploy PostgreSQL Cluster
We are going to Deploy PostgreSQL Cluster using KubeDB. First, let’s create a Namespace in which we will deploy the database.
$ kubectl create namespace demo
namespace/demo created
Here is the yaml of the PostgreSQL CR we are going to use:
apiVersion: kubedb.com/v1alpha2
kind: Postgres
metadata:
name: postgres-cluster
namespace: demo
spec:
version: "16.1"
replicas: 3
standbyMode: Hot
storageType: Durable
storage:
storageClassName: "gp2"
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
terminationPolicy: WipeOut
Let’s save this yaml configuration into postgres-cluster.yaml
Then create the above PostgreSQL CR
$ kubectl apply -f postgres-cluster.yaml
postgres.kubedb.com/postgres-cluster created
In this yaml,
- In this yaml we can see in the
spec.versionfield specifies the version of PostgreSQL. Here, we are using PostgreSQL16.1. You can list the KubeDB supported versions of PostgreSQL by running$ kubectl get postgresversionscommand. spec.storage.storageClassNameis the name of the StorageClass used to provision PVCs.spec.terminationPolicyfield is Wipeout means that the database will be deleted without restrictions. It can also be “Halt”, “Delete” and “DoNotTerminate”. Learn More about these checkout Termination Policy .
Once these are handled correctly and the PostgreSQL object is deployed, you will see that the following objects are created:
$ kubectl get all -n demo
NAME READY STATUS RESTARTS AGE
pod/postgres-cluster-0 2/2 Running 0 3m37s
pod/postgres-cluster-1 2/2 Running 0 43s
pod/postgres-cluster-2 2/2 Running 0 34s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/postgres-cluster ClusterIP 10.96.117.56 <none> 5432/TCP,2379/TCP 4m22s
service/postgres-cluster-pods ClusterIP None <none> 5432/TCP,2380/TCP,2379/TCP 4m22s
service/postgres-cluster-standby ClusterIP 10.96.131.2 <none> 5432/TCP 4m22s
NAME READY AGE
statefulset.apps/postgres-cluster 3/3 3m37s
NAME TYPE VERSION AGE
appbinding.appcatalog.appscode.com/postgres-cluster kubedb.com/postgres 16.1 3m37s
NAME VERSION STATUS AGE
postgres.kubedb.com/postgres-cluster 16.1 Ready 4m22s
Let’s check if the database is ready to use,
$ kubectl get postgres -n demo postgres-cluster
NAME VERSION STATUS AGE
postgres-cluster 16.1 Ready 4m59s
We have successfully deployed PostgreSQL cluster in AWS. Now we can exec into the container to use the database.
Accessing Database Through CLI
To access the database through CLI, we have to get the credentials to access. KubeDB will create Secret and Service for the database postgres-cluster that we have deployed. Let’s check them using the following commands,
$ kubectl get secret -n demo -l=app.kubernetes.io/instance=postgres-cluster
NAME TYPE DATA AGE
postgres-cluster-auth kubernetes.io/basic-auth 2 7m25s
$ kubectl get service -n demo -l=app.kubernetes.io/instance=postgres-cluster
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
postgres-cluster ClusterIP 10.96.117.56 <none> 5432/TCP,2379/TCP 7m40s
postgres-cluster-pods ClusterIP None <none> 5432/TCP,2380/TCP,2379/TCP 7m40s
postgres-cluster-standby ClusterIP 10.96.131.2 <none> 5432/TCP 7m40s
Now, we are going to use postgres-cluster-auth to get the credentials.
$ kubectl get secrets -n demo postgres-cluster-auth -o jsonpath='{.data.username}' | base64 -d
postgres
$ kubectl get secrets -n demo postgres-cluster-auth -o jsonpath='{.data.password}' | base64 -d
LxZOBQbhB;k7PB2R
Insert Sample Data
In this section, we are going to login into our PostgreSQL database pod and insert some sample data.
$ kubectl exec -it postgres-cluster-0 -n demo -c postgres -- bash
postgres-cluster-0:/$ psql -d "user=postgres password=LxZOBQbhB;k7PB2R"
psql (16.1)
Type "help" for help.
postgres=# \l
List of databases
Name | Owner | Encoding | Locale Provider | Collate | Ctype | ICU Locale | ICU Rules | Access privileges
---------------+----------+----------+-----------------+------------+------------+------------+-----------+-----------------------
kubedb_system | postgres | UTF8 | libc | en_US.utf8 | en_US.utf8 | | |
postgres | postgres | UTF8 | libc | en_US.utf8 | en_US.utf8 | | |
template0 | postgres | UTF8 | libc | en_US.utf8 | en_US.utf8 | | | =c/postgres +
| | | | | | | | postgres=CTc/postgres
template1 | postgres | UTF8 | libc | en_US.utf8 | en_US.utf8 | | | =c/postgres +
| | | | | | | | postgres=CTc/postgres
(4 rows)
postgres=# CREATE DATABASE music;
CREATE DATABASE
postgres=# \l
List of databases
Name | Owner | Encoding | Locale Provider | Collate | Ctype | ICU Locale | ICU Rules | Access privileges
---------------+----------+----------+-----------------+------------+------------+------------+-----------+-----------------------
kubedb_system | postgres | UTF8 | libc | en_US.utf8 | en_US.utf8 | | |
music | postgres | UTF8 | libc | en_US.utf8 | en_US.utf8 | | |
postgres | postgres | UTF8 | libc | en_US.utf8 | en_US.utf8 | | |
template0 | postgres | UTF8 | libc | en_US.utf8 | en_US.utf8 | | | =c/postgres +
| | | | | | | | postgres=CTc/postgres
template1 | postgres | UTF8 | libc | en_US.utf8 | en_US.utf8 | | | =c/postgres +
| | | | | | | | postgres=CTc/postgres
(5 rows)
postgres=# CREATE TABLE artist (name VARCHAR(50) NOT NULL, song VARCHAR(50) NOT NULL);
CREATE TABLE
postgres=# INSERT INTO artist (name, song) VALUES('BOBBY BARE', 'FIVE HUNDRED MILES');
INSERT 0 1
postgres=# SELECT * FROM artist;
name | song
------------+--------------------
BOBBY BARE | FIVE HUNDRED MILES
(1 row)
postgres=# \q
postgres-cluster-0:/$ exit
exit
We’ve successfully inserted some sample data to our database. More information about Run & Manage PostgreSQL on Kubernetes can be found in Kubernetes PostgreSQL
Horizontal Scaling of PostgreSQL Cluster
Horizontal Scale Up
Here, we are going to scale up the replicas of the PostgreSQL cluster replicaset to meet the desired number of replicas after scaling. Before applying Horizontal Scaling, let’s check the current number of replicas,
$ kubectl get postgres -n demo postgres-cluster -o json | jq '.spec.replicas'
3
Create PostgresOpsRequest
In order to scale up, we have to create a PostgresOpsRequest CR with our desired replicas. Let’s create it using this following yaml,
apiVersion: ops.kubedb.com/v1alpha1
kind: PostgresOpsRequest
metadata:
name: horizontal-scale-up
namespace: demo
spec:
type: HorizontalScaling
databaseRef:
name: postgres-cluster
horizontalScaling:
replicas: 5
In this yaml,
spec.databaseRef.namespecifies that we are performing horizontal scaling operation onpostgres-clusterdatabase.spec.typespecifies that we are performingHorizontalScalingon our database.spec.horizontalScaling.replicasspecifies the desired number of replicas after scaling.
Let’s save this yaml configuration into horizontal-scale-up.yaml and apply it,
$ kubectl apply -f horizontal-scale-up.yaml
postgresopsrequest.ops.kubedb.com/horizontal-scale-up created
Let’s wait for PostgresOpsRequest STATUS to be Successful. Run the following command to watch PostgresOpsRequest CR,
$ watch kubectl get postgresopsrequest -n demo
NAME TYPE STATUS AGE
horizontal-scale-up HorizontalScaling Successful 97s
From the above output we can see that the PostgresOpsRequest has succeeded. Now, we are going to verify the number of replicas,
$ kubectl get postgres -n demo postgres-cluster -o json | jq '.spec.replicas'
5
From all the above outputs we can see that the replicas of the cluster is now increased to 5. That means we have successfully scaled up the replicas of the PostgreSQL cluster.
Horizontal Scale Down
Now, we are going to scale down the replicas of the cluster to meet the desired number of replicas after scaling.
Create PostgresOpsRequest
In order to scale down, again we need to create a PostgresOpsRequest CR with our desired replicas. Let’s create it using this following yaml,
apiVersion: ops.kubedb.com/v1alpha1
kind: PostgresOpsRequest
metadata:
name: horizontal-scale-down
namespace: demo
spec:
type: HorizontalScaling
databaseRef:
name: postgres-cluster
horizontalScaling:
replicas: 3
In this yaml,
spec.databaseRef.namespecifies that we are performing horizontal scaling operation onpostgres-clusterdatabase.spec.typespecifies that we are performingHorizontalScalingon our database.spec.horizontalScaling.replicasspecifies the desired number of replicas after scaling.
Let’s save this yaml configuration into horizontal-scale-down.yaml and apply it,
$ kubectl apply -f horizontal-scale-down.yaml
postgresopsrequest.ops.kubedb.com/horizontal-scale-down created
Let’s wait for PostgresOpsRequest STATUS to be Successful. Run the following command to watch PostgresOpsRequest CR,
$ watch kubectl get postgresopsrequest -n demo
NAME TYPE STATUS AGE
horizontal-scale-down HorizontalScaling Successful 2m33s
From the above output we can see that the PostgresOpsRequest has succeeded. Now, we are going to verify the number of replicas,
$ kubectl get postgres -n demo postgres-cluster -o json | jq '.spec.replicas'
3
From all the above outputs we can see that the replicas of the cluster is decreased to 3. That means we have successfully scaled down the replicas of the PostgreSQL cluster.
If you want to learn more about Production-Grade PostgreSQL on Kubernetes you can have a look into that playlist below:
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More about PostgreSQL in Kubernetes
If you have found a bug with KubeDB or want to request for new features, please file an issue .