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 that KubeDB supports are MongoDB, Elasticsearch, MySQL, Kafka, MariaDB, Redis, PostgreSQL, ProxySQL, Percona XtraDB, Memcached and PgBouncer. You can find the guides to all the supported databases in KubeDB . In this tutorial we will deploy Highly Available PostgreSQL Cluster in Azure Kubernetes Service (AKS). We will cover the following steps:
- Install KubeDB
- Deploy PostgreSQL Cluster
- Horizontal Scaling of PostgreSQL Cluster
- Vertical 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}'
fc435a61-c74b-9243-83a5-f1110ef2462c
Get License
Go to Appscode License Server to get the license.txt file. For this tutorial we will use KubeDB Enterprise Edition.
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 repo add appscode https://charts.appscode.com/stable/
$ helm repo update
$ helm search repo appscode/kubedb
NAME CHART VERSION APP VERSION DESCRIPTION
appscode/kubedb v2023.06.19 v2023.06.19 KubeDB by AppsCode - Production ready databases...
appscode/kubedb-autoscaler v0.19.0 v0.19.0 KubeDB Autoscaler by AppsCode - Autoscale KubeD...
appscode/kubedb-catalog v2023.06.19 v2023.06.19 KubeDB Catalog by AppsCode - Catalog for databa...
appscode/kubedb-community v0.24.2 v0.24.2 KubeDB Community by AppsCode - Community featur...
appscode/kubedb-crds v2023.06.19 v2023.06.19 KubeDB Custom Resource Definitions
appscode/kubedb-dashboard v0.10.0 v0.10.0 KubeDB Dashboard by AppsCode
appscode/kubedb-enterprise v0.11.2 v0.11.2 KubeDB Enterprise by AppsCode - Enterprise feat...
appscode/kubedb-grafana-dashboards v2023.06.19 v2023.06.19 A Helm chart for kubedb-grafana-dashboards by A...
appscode/kubedb-metrics v2023.06.19 v2023.06.19 KubeDB State Metrics
appscode/kubedb-one v2023.06.19 v2023.06.19 KubeDB and Stash by AppsCode - Production ready...
appscode/kubedb-ops-manager v0.21.0 v0.21.0 KubeDB Ops Manager by AppsCode - Enterprise fea...
appscode/kubedb-opscenter v2023.06.19 v2023.06.19 KubeDB Opscenter by AppsCode
appscode/kubedb-provisioner v0.34.0 v0.34.0 KubeDB Provisioner by AppsCode - Community feat...
appscode/kubedb-schema-manager v0.10.0 v0.10.0 KubeDB Schema Manager by AppsCode
appscode/kubedb-ui v2023.03.23 0.3.28 A Helm chart for Kubernetes
appscode/kubedb-ui-server v2021.12.21 v2021.12.21 A Helm chart for kubedb-ui-server by AppsCode
appscode/kubedb-webhook-server v0.10.0 v0.10.0 KubeDB Webhook Server by AppsCode
# Install KubeDB Enterprise operator chart
$ helm install kubedb appscode/kubedb \
--version v2023.06.19 \
--namespace kubedb --create-namespace \
--set kubedb-provisioner.enabled=true \
--set kubedb-ops-manager.enabled=true \
--set kubedb-autoscaler.enabled=true \
--set kubedb-dashboard.enabled=true \
--set kubedb-schema-manager.enabled=true \
--set-file global.license=/path/to/the/license.txt
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-79b488f4d9-7t524 1/1 Running 0 2m1s
kubedb kubedb-kubedb-dashboard-77d6d5c598-9zs6j 1/1 Running 0 2m1s
kubedb kubedb-kubedb-ops-manager-65f8d87769-dhmds 1/1 Running 0 2m1s
kubedb kubedb-kubedb-provisioner-7ffb8767c8-s6txh 1/1 Running 0 2m1s
kubedb kubedb-kubedb-schema-manager-848fcb975b-8jn6j 1/1 Running 0 2m1s
kubedb kubedb-kubedb-webhook-server-678d69f669-swnbf 1/1 Running 0 2m1s
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
elasticsearchautoscalers.autoscaling.kubedb.com 2023-07-24T08:41:07Z
elasticsearchdashboards.dashboard.kubedb.com 2023-07-24T08:41:05Z
elasticsearches.kubedb.com 2023-07-24T08:41:05Z
elasticsearchopsrequests.ops.kubedb.com 2023-07-24T08:41:32Z
elasticsearchversions.catalog.kubedb.com 2023-07-24T08:38:37Z
etcds.kubedb.com 2023-07-24T08:41:27Z
etcdversions.catalog.kubedb.com 2023-07-24T08:38:37Z
kafkas.kubedb.com 2023-07-24T08:42:02Z
kafkaversions.catalog.kubedb.com 2023-07-24T08:38:38Z
mariadbautoscalers.autoscaling.kubedb.com 2023-07-24T08:41:07Z
mariadbdatabases.schema.kubedb.com 2023-07-24T08:41:29Z
mariadbopsrequests.ops.kubedb.com 2023-07-24T08:42:50Z
mariadbs.kubedb.com 2023-07-24T08:41:28Z
mariadbversions.catalog.kubedb.com 2023-07-24T08:38:38Z
memcacheds.kubedb.com 2023-07-24T08:41:28Z
memcachedversions.catalog.kubedb.com 2023-07-24T08:38:38Z
mongodbautoscalers.autoscaling.kubedb.com 2023-07-24T08:41:08Z
mongodbdatabases.schema.kubedb.com 2023-07-24T08:41:22Z
mongodbopsrequests.ops.kubedb.com 2023-07-24T08:41:37Z
mongodbs.kubedb.com 2023-07-24T08:41:23Z
mongodbversions.catalog.kubedb.com 2023-07-24T08:38:39Z
mysqlautoscalers.autoscaling.kubedb.com 2023-07-24T08:41:08Z
mysqldatabases.schema.kubedb.com 2023-07-24T08:41:19Z
mysqlopsrequests.ops.kubedb.com 2023-07-24T08:42:46Z
mysqls.kubedb.com 2023-07-24T08:41:19Z
mysqlversions.catalog.kubedb.com 2023-07-24T08:38:39Z
perconaxtradbautoscalers.autoscaling.kubedb.com 2023-07-24T08:41:08Z
perconaxtradbopsrequests.ops.kubedb.com 2023-07-24T08:44:09Z
perconaxtradbs.kubedb.com 2023-07-24T08:41:51Z
perconaxtradbversions.catalog.kubedb.com 2023-07-24T08:38:39Z
pgbouncers.kubedb.com 2023-07-24T08:41:53Z
pgbouncerversions.catalog.kubedb.com 2023-07-24T08:38:40Z
postgresautoscalers.autoscaling.kubedb.com 2023-07-24T08:41:08Z
postgresdatabases.schema.kubedb.com 2023-07-24T08:41:27Z
postgreses.kubedb.com 2023-07-24T08:41:28Z
postgresopsrequests.ops.kubedb.com 2023-07-24T08:43:59Z
postgresversions.catalog.kubedb.com 2023-07-24T08:38:40Z
proxysqlautoscalers.autoscaling.kubedb.com 2023-07-24T08:41:08Z
proxysqlopsrequests.ops.kubedb.com 2023-07-24T08:44:04Z
proxysqls.kubedb.com 2023-07-24T08:41:59Z
proxysqlversions.catalog.kubedb.com 2023-07-24T08:38:40Z
publishers.postgres.kubedb.com 2023-07-24T08:45:38Z
redisautoscalers.autoscaling.kubedb.com 2023-07-24T08:41:08Z
redises.kubedb.com 2023-07-24T08:42:01Z
redisopsrequests.ops.kubedb.com 2023-07-24T08:43:47Z
redissentinelautoscalers.autoscaling.kubedb.com 2023-07-24T08:41:08Z
redissentinelopsrequests.ops.kubedb.com 2023-07-24T08:45:28Z
redissentinels.kubedb.com 2023-07-24T08:42:02Z
redisversions.catalog.kubedb.com 2023-07-24T08:38:41Z
subscribers.postgres.kubedb.com 2023-07-24T08:45:46Z
Deploy PostgreSQL Cluster
We are going to Deploy PostgreSQL Cluster by 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 CRO we are going to use:
apiVersion: kubedb.com/v1alpha2
kind: Postgres
metadata:
name: postgres-cluster
namespace: demo
spec:
version: "15.1"
replicas: 3
standbyMode: Hot
storageType: Durable
storage:
storageClassName: "default"
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
terminationPolicy: WipeOut
Let’s save this yaml configuration into postgres-cluster.yaml
Then create the above PostgreSQL CRO
$ 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 PostgreSQLversion 15.1. You can list the KubeDB supported versions of PostgreSQL by runningkubectl get postgresversionscommand. spec.standbyis an optional field that specifies the standby modehotorwarmto use for standby replicas. Inhotstandby mode, standby replicas can accept connection and run read-only queries. Inwarmstandby mode, standby replicas can’t accept connection and only used for replication purpose.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 3m25s
pod/postgres-cluster-1 2/2 Running 0 3m4s
pod/postgres-cluster-2 2/2 Running 0 2m4s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/postgres-cluster ClusterIP 10.100.248.168 <none> 5432/TCP,2379/TCP 3m30s
service/postgres-cluster-pods ClusterIP None <none> 5432/TCP,2380/TCP,2379/TCP 3m30s
service/postgres-cluster-standby ClusterIP 10.100.106.115 <none> 5432/TCP 3m30s
NAME READY AGE
statefulset.apps/postgres-cluster 3/3 3m32s
NAME TYPE VERSION AGE
appbinding.appcatalog.appscode.com/postgres-cluster kubedb.com/postgres 15.1 3m36s
NAME VERSION STATUS AGE
postgres.kubedb.com/postgres-cluster 15.1 Ready 3m59s
Let’s check if the database is ready to use,
$ kubectl get pg -n demo postgres-cluster
NAME VERSION STATUS AGE
postgres-cluster 15.1 Ready 5m
We have successfully deployed PostgreSQL cluster in AKS. 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 5m34s
$ kubectl get service -n demo -l=app.kubernetes.io/instance=postgres-cluster
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
postgres-cluster ClusterIP 10.100.248.168 <none> 5432/TCP,2379/TCP 5m57s
postgres-cluster-pods ClusterIP None <none> 5432/TCP,2380/TCP,2379/TCP 5m57s
postgres-cluster-standby ClusterIP 10.100.106.115 <none> 5432/TCP 5m57s
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
2*SLD7YieS2)9jPc
Insert Sample Data
In this section, we are going to login into our PostgreSQL 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=2*SLD7YieS2)9jPc"
psql (15.1)
Type "help" for help.
postgres=# \l
List of databases
Name | Owner | Encoding | Collate | Ctype | ICU Locale | Locale Provider | Access privileges
---------------+----------+----------+------------+------------+------------+-----------------+-----------------------
kubedb_system | postgres | UTF8 | en_US.utf8 | en_US.utf8 | | libc |
postgres | postgres | UTF8 | en_US.utf8 | en_US.utf8 | | libc |
template0 | postgres | UTF8 | en_US.utf8 | en_US.utf8 | | libc | =c/postgres +
| | | | | | | postgres=CTc/postgres
template1 | postgres | UTF8 | en_US.utf8 | en_US.utf8 | | libc | =c/postgres +
| | | | | | | postgres=CTc/postgres
(4 rows)
postgres=# CREATE DATABASE music;
CREATE DATABASE
postgres=# \l
List of databases
Name | Owner | Encoding | Collate | Ctype | ICU Locale | Locale Provider | Access privileges
---------------+----------+----------+------------+------------+------------+-----------------+-----------------------
kubedb_system | postgres | UTF8 | en_US.utf8 | en_US.utf8 | | libc |
music | postgres | UTF8 | en_US.utf8 | en_US.utf8 | | libc |
postgres | postgres | UTF8 | en_US.utf8 | en_US.utf8 | | libc |
template0 | postgres | UTF8 | en_US.utf8 | en_US.utf8 | | libc | =c/postgres +
| | | | | | | postgres=CTc/postgres
template1 | postgres | UTF8 | en_US.utf8 | en_US.utf8 | | libc | =c/postgres +
| | | | | | | postgres=CTc/postgres
(5 rows)
postgres=# \c music
You are now connected to database "music" as user "postgres".
music=# CREATE TABLE artist (name VARCHAR(50) NOT NULL, song VARCHAR(50) NOT NULL);
CREATE TABLE
music=# INSERT INTO artist (name, song) VALUES('John Denver', 'Country Roads');
INSERT 0 1
music=# SELECT * FROM artist;
name | song
-------------+---------------
John Denver | Country Roads
(1 row)
music=# \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 PostgreSQL Kubernetes
Horizontal Scaling of PostgreSQL Cluster
Horizontal Scale Up
Here, we are going to increase the number of PostgreSQL replicas to meet the desired number of replicas. Before applying Horizontal Scaling, let’s check the current number of PostgreSQL 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 3m46s
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 number of replicas is now increased to 5. That means we have successfully scaled up the number of PostgreSQL replicas.
Horizontal Scale Down
Now, we are going to scale down the number of PostgreSQL replicas to meet the desired number of replicas.
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 3m21s
From the above output we can see that the PostgresOpsRequest has succeeded. Now, we are going to verify the number of PostgreSQL replicas,
$ kubectl get postgres -n demo postgres-cluster -o json | jq '.spec.replicas'
3
From all the above outputs we can see that the number of replicas is now decreased to 3. That means we have successfully scaled down the number of PostgreSQL replicas.
Vetical Scaling of PostgreSQL Cluster
We are going to scale up the current cpu resource of the PostgreSQL cluster by applying Vertical Scaling. Before applying it, let’s check the current resources,
$ kubectl get pod -n demo postgres-cluster-0 -o json | jq '.spec.containers[].resources'
{
"limits": {
"memory": "1Gi"
},
"requests": {
"cpu": "500m",
"memory": "1Gi"
}
}
{}
Vertical Scale Up
Create PostgresOpsRequest
In order to update the resources of the cluster, we have to create a PostgresOpsRequest CR with our desired resources. Let’s create it using this following yaml,
apiVersion: ops.kubedb.com/v1alpha1
kind: PostgresOpsRequest
metadata:
name: vertical-scale-up
namespace: demo
spec:
type: VerticalScaling
databaseRef:
name: postgres-cluster
verticalScaling:
postgres:
requests:
memory: "1100Mi"
cpu: "0.55"
limits:
memory: "1100Mi"
cpu: "0.55"
In this yaml,
spec.databaseRef.namespecifies that we are performing vertical scaling operation onpostgres-clusterdatabase.spec.typespecifies that we are performingVerticalScalingon our database.spec.verticalScaling.replicaSetspecifies the desired resources after scaling.
Let’s save this yaml configuration into vertical-scale-up.yaml and apply it,
$ kubectl apply -f vertical-scale-up.yaml
postgresopsrequest.ops.kubedb.com/vertical-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
vertical-scale-up VerticalScaling Successful 3m45s
We can see from the above output that the PostgresOpsRequest has succeeded. Now, we are going to verify from one of the Pod yaml whether the resources of the database has updated to meet up the desired state. Let’s check with the following command,
$ kubectl get pod -n demo postgres-cluster-0 -o json | jq '.spec.containers[].resources'
{
"limits": {
"cpu": "550m",
"memory": "1100Mi"
},
"requests": {
"cpu": "550m",
"memory": "1100Mi"
}
}
{}
The above output verifies that we have successfully scaled up the resources of the PostgreSQL cluster.
Vertical Scale Down
Create PostgresOpsRequest
In order to update the resources of the database, we have to create a PostgresOpsRequest CR with our desired resources. Let’s create it using this following yaml,
apiVersion: ops.kubedb.com/v1alpha1
kind: PostgresOpsRequest
metadata:
name: vertical-scale-down
namespace: demo
spec:
type: VerticalScaling
databaseRef:
name: postgres-cluster
verticalScaling:
postgres:
requests:
memory: "1Gi"
cpu: "0.5"
limits:
memory: "1Gi"
cpu: "0.5"
In this yaml,
spec.databaseRef.namespecifies that we are performing vertical scaling operation onpostgres-clusterdatabase.spec.typespecifies that we are performingVerticalScalingon our database.spec.verticalScaling.replicaSetspecifies the desired resources after scaling.
Let’s save this yaml configuration into vertical-scale-down.yaml and apply it,
$ kubectl apply -f vertical-scale-down.yaml
postgresopsrequest.ops.kubedb.com/vertical-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
vertical-scale-down VerticalScaling Successful 4m2s
We can see from the above output that the PostgresOpsRequest has succeeded. Now, we are going to verify from one of the Pod yaml whether the resources of the database has updated to meet up the desired state. Let’s check with the following command,
$ kubectl get pod -n demo postgres-cluster-0 -o json | jq '.spec.containers[].resources'
{
"limits": {
"cpu": "500m",
"memory": "1Gi"
},
"requests": {
"cpu": "500m",
"memory": "1Gi"
}
}
The above output verifies that we have successfully scaled down the resources of the PostgreSQL cluster.
If you want to learn more about Production-Grade PostgreSQL you can have a look into that playlist below:
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Learn more about PostgreSQL in Kubernetes
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