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Vertical Scale Postgres Instance
This guide will show you how to use kubeDB-Ops-Manager to update the resources of a Postgres instance.
Before You Begin
At first, you need to have a Kubernetes cluster, and the
kubectlcommand-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.Install
KubeDB-ProvisionerandkubeDB-Ops-Managerin your cluster following the steps here.You should be familiar with the following
KubeDBconcepts:
To keep everything isolated, we are going to use 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/guides/postgres/scaling/vertical-scaling/scale-vertically/yamls directory of kubedb/doc repository.
Apply Vertical Scaling on Postgres Instance
Here, we are going to deploy a Postgres instance using a supported version by KubeDB operator. Then we are going to apply vertical scaling on it.
Find supported Postgres Version:
When you have installed KubeDB, it has created PostgresVersion CR for all supported Postgres versions. Let’s check the supported Postgres versions,
$ kubectl get postgresversion
NAME VERSION DISTRIBUTION DB_IMAGE DEPRECATED AGE
10.16 10.16 Official postgres:10.16-alpine 63s
10.16-debian 10.16 Official postgres:10.16 63s
10.19 10.19 Official postgres:10.19-bullseye 63s
10.19-bullseye 10.19 Official postgres:10.19-bullseye 63s
11.11 11.11 Official postgres:11.11-alpine 63s
11.11-debian 11.11 Official postgres:11.11 63s
11.14 11.14 Official postgres:11.14-alpine 63s
11.14-bullseye 11.14 Official postgres:11.14-bullseye 63s
11.14-bullseye-postgis 11.14 PostGIS postgis/postgis:11-3.1 63s
12.6 12.6 Official postgres:12.6-alpine 63s
12.6-debian 12.6 Official postgres:12.6 63s
12.9 12.9 Official postgres:12.9-alpine 63s
12.9-bullseye 12.9 Official postgres:12.9-bullseye 63s
12.9-bullseye-postgis 12.9 PostGIS postgis/postgis:12-3.1 63s
13.2 13.2 Official postgres:13.2-alpine 63s
13.2-debian 13.2 Official postgres:13.2 63s
13.5 13.5 Official postgres:13.5-alpine 63s
13.5-bullseye 13.5 Official postgres:13.5-bullseye 63s
13.5-bullseye-postgis 13.5 PostGIS postgis/postgis:13-3.1 63s
14.1 14.1 Official postgres:14.1-alpine 63s
14.1-bullseye 14.1 Official postgres:14.1-bullseye 63s
14.1-bullseye-postgis 14.1 PostGIS postgis/postgis:14-3.1 63s
9.6.21 9.6.21 Official postgres:9.6.21-alpine 63s
9.6.21-debian 9.6.21 Official postgres:9.6.21 63s
9.6.24 9.6.24 Official postgres:9.6.24-alpine 63s
9.6.24-bullseye 9.6.24 Official postgres:9.6.24-bullseye 63s
timescaledb-2.1.0-pg11 11.11 TimescaleDB timescale/timescaledb:2.1.0-pg11-oss 63s
timescaledb-2.1.0-pg12 12.6 TimescaleDB timescale/timescaledb:2.1.0-pg12-oss 63s
timescaledb-2.1.0-pg13 13.2 TimescaleDB timescale/timescaledb:2.1.0-pg13-oss 63s
timescaledb-2.5.0-pg14.1 14.1 TimescaleDB timescale/timescaledb:2.5.0-pg14-oss 63s
The version above that does not show DEPRECATED true is supported by KubeDB for Postgres. You can use any non-deprecated version. Here, we are going to create a postgres using non-deprecated Postgres version 13.2.
Deploy Postgres:
In this section, we are going to deploy a Postgres instance. Then, in the next section, we will update the resources of the database server using vertical scaling. Below is the YAML of the Postgres cr that we are going to create,
apiVersion: kubedb.com/v1alpha2
kind: Postgres
metadata:
name: pg
namespace: demo
spec:
version: "13.2"
replicas: 3
standbyMode: Hot
storageType: Durable
storage:
storageClassName: "standard"
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
terminationPolicy: WipeOut
Let’s create the Postgres cr we have shown above,
$ kubectl create -f https://github.com/kubedb/docs/raw/v2023.04.10/docs/guides/postgres/scaling/vertical-scaling/scale-vertically/yamls/postgres.yaml
postgres.kubedb.com/pg created
Check postgres Ready to Scale:
KubeDB-Provisioner watches for Postgres objects using Kubernetes API. When a Postgres object is created, KubeDB-Provisioner will create a new StatefulSet, Services, and Secrets, etc.
Now, watch Postgres is going to be in Running state and also watch StatefulSet and its pod is created and going to be in Running state,
$ watch -n 3 kubectl get postgres -n demo pg
Every 3.0s: kubectl get postgres -n demo pg emon-r7: Thu Dec 2 10:53:54 2021
NAME VERSION STATUS AGE
pg 13.2 Ready 3m16s
$ watch -n 3 kubectl get sts -n demo pg
Every 3.0s: kubectl get sts -n demo pg emon-r7: Thu Dec 2 10:54:31 2021
NAME READY AGE
pg 3/3 3m54s
$ watch -n 3 kubectl get pod -n demo
Every 3.0s: kubectl get pod -n demo emon-r7: Thu Dec 2 10:55:29 2021
NAME READY STATUS RESTARTS AGE
pg-0 2/2 Running 0 4m51s
pg-1 2/2 Running 0 3m50s
pg-2 2/2 Running 0 3m46s
Let’s check the pg-0 Pod’s postgres container’s resources, As there are two containers, And Postgres container is the first container So it’s index will be 0.
$ kubectl get pod -n demo pg-0 -o json | jq '.spec.containers[0].resources'
{
"limits": {
"memory": "1Gi"
},
"requests": {
"cpu": "500m",
"memory": "1Gi"
}
}
Now, We are ready to apply a vertical scale on this postgres database.
Vertical Scaling
Here, we are going to update the resources of the postgres to meet up with the desired resources after scaling.
Create PostgresOpsRequest:
In order to update the resources of your database, you have to create a PostgresOpsRequest cr with your desired resources after scaling. Below is the YAML of the PostgresOpsRequest cr that we are going to create,
apiVersion: ops.kubedb.com/v1alpha1
kind: PostgresOpsRequest
metadata:
name: pg-scale-vertical
namespace: demo
spec:
type: VerticalScaling
databaseRef:
name: pg
verticalScaling:
postgres:
requests:
memory: "1200Mi"
cpu: "0.7"
limits:
memory: "1200Mi"
cpu: "0.7"
Here,
spec.databaseRef.namespecifies that we are performing operation onpgPostgresdatabase.spec.typespecifies that we are performingVerticalScalingon our database.spec.VerticalScaling.postgresspecifies the expected postgres container resources after scaling.
Let’s create the PostgresOpsRequest cr we have shown above,
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2023.04.10/docs/guides/postgres/scaling/vertical-scaling/scale-vertically/yamls/pg-vertical-scaling.yaml
postgresopsrequest.ops.kubedb.com/pg-scale-vertical created
Verify Postgres resources updated successfully:
If everything goes well, KubeDB-Ops-Manager will update the resources of the StatefulSet’s Pod containers. After a successful scaling process is done, the KubeDB-Ops-Manager updates the resources of the Postgres object.
First, we will wait for PostgresOpsRequest to be successful. Run the following command to watch PostgresOpsRequest cr,
$ watch kubectl get postgresopsrequest -n demo pg-scale-vertical
Every 2.0s: kubectl get postgresopsrequest -n demo pg-scale-ve... emon-r7: Thu Dec 2 11:09:49 2021
NAME TYPE STATUS AGE
pg-scale-vertical VerticalScaling Successful 3m42s
We can see from the above output that the PostgresOpsRequest has succeeded. If we describe the PostgresOpsRequest, we will see that the postgres resources are updated.
$ kubectl describe postgresopsrequest -n demo pg-scale-vertical
Name: pg-scale-vertical
Namespace: demo
Labels: <none>
Annotations: <none>
API Version: ops.kubedb.com/v1alpha1
Kind: PostgresOpsRequest
Metadata:
Creation Timestamp: 2021-12-02T05:06:07Z
Generation: 1
Managed Fields:
API Version: ops.kubedb.com/v1alpha1
Fields Type: FieldsV1
fieldsV1:
f:metadata:
f:annotations:
.:
f:kubectl.kubernetes.io/last-applied-configuration:
f:spec:
.:
f:databaseRef:
.:
f:name:
f:type:
f:verticalScaling:
.:
f:postgres:
.:
f:limits:
.:
f:cpu:
f:memory:
f:requests:
.:
f:cpu:
f:memory:
Manager: kubectl-client-side-apply
Operation: Update
Time: 2021-12-02T05:06:07Z
API Version: ops.kubedb.com/v1alpha1
Fields Type: FieldsV1
fieldsV1:
f:status:
.:
f:conditions:
f:observedGeneration:
f:phase:
Manager: kubedb-enterprise
Operation: Update
Time: 2021-12-02T05:06:07Z
Resource Version: 8452
UID: 92d1e69f-c99a-4d0b-b8bf-e904e1336083
Spec:
Database Ref:
Name: pg
Type: VerticalScaling
Vertical Scaling:
Postgres:
Limits:
Cpu: 0.7
Memory: 1200Mi
Requests:
Cpu: 0.7
Memory: 1200Mi
Status:
Conditions:
Last Transition Time: 2021-12-02T05:06:07Z
Message: Postgres ops request is vertically scaling database
Observed Generation: 1
Reason: Progressing
Status: True
Type: Progressing
Last Transition Time: 2021-12-02T05:06:07Z
Message: Successfully updated statefulsets resources
Observed Generation: 1
Reason: UpdateStatefulSetResources
Status: True
Type: UpdateStatefulSetResources
Last Transition Time: 2021-12-02T05:08:02Z
Message: SuccessfullyPerformedVerticalScaling
Observed Generation: 1
Reason: VerticalScaling
Status: True
Type: VerticalScaling
Last Transition Time: 2021-12-02T05:08:02Z
Message: Successfully Vertically Scaled Database
Observed Generation: 1
Reason: Successful
Status: True
Type: Successful
Observed Generation: 1
Phase: Successful
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal PauseDatabase 4m17s KubeDB Enterprise Operator Pausing Postgres demo/pg
Normal PauseDatabase 4m17s KubeDB Enterprise Operator Successfully paused Postgres demo/pg
Normal VerticalScaling 2m22s KubeDB Enterprise Operator SuccessfullyPerformedVerticalScaling
Normal ResumeDatabase 2m22s KubeDB Enterprise Operator Resuming PostgreSQL demo/pg
Normal ResumeDatabase 2m22s KubeDB Enterprise Operator Successfully resumed PostgreSQL demo/pg
Normal Successful 2m22s KubeDB Enterprise Operator Successfully Vertically Scaled Database
Now, we are going to verify whether the resources of the postgres instance has updated to meet up the desired state, Let’s check,
$ kubectl get pod -n demo pg-0 -o json | jq '.spec.containers[0].resources'
{
"limits": {
"cpu": "700m",
"memory": "1200Mi"
},
"requests": {
"cpu": "700m",
"memory": "1200Mi"
}
}
The above output verifies that we have successfully scaled up the resources of the Postgres.
Cleaning Up
To clean up the Kubernetes resources created by this tutorial, run:
kubectl delete postgres -n demo pg
kubectl delete postgresopsrequest -n demo pg-scale-vertical