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Vertical Scale Postgres Standalone
This guide will show you how to use KubeDB enterprise operator to update the resources of a standalone.
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.
Install KubeDB community and enterprise operator in your cluster following the steps here.
You should be familiar with the following KubeDB concepts:
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/standalone/yamls directory of kubedb/doc repository.
Apply Vertical Scaling on Standalone
Here, we are going to deploy a Postgres standalone using a supported version by KubeDB operator. Then we are going to apply vertical scaling on it.
Prepare Group Replication
At first, we are going to deploy a standalone using supported Postgres version. Then, we are going to update the resources of the database server through vertical scaling.
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 standalone using non-deprecated Postgres version 8.0.27.
Deploy Postgres Standalone:
In this section, we are going to deploy a Postgres standalone. 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/v2021.11.24/docs/guides/postgres/scaling/vertical-scaling/standalone/yamls/standalone.yaml
postgres.kubedb.com/my-standalone created
Check Standalone Ready to Scale:
KubeDB operator watches for Postgres objects using Kubernetes API. When a Postgres object is created, KubeDB operator will create a new StatefulSet, Services, and Secrets, etc.
Now, watch Postgres is going to Running state and also watch StatefulSet and its pod is created and going to Running state,
$ watch -n 3 kubectl get my -n demo my-standalone
Every 3.0s: kubectl get my -n demo my-standalone suaas-appscode: Wed Jul 1 17:48:14 2020
NAME VERSION STATUS AGE
my-standalone 8.0.27 Running 2m58s
$ watch -n 3 kubectl get sts -n demo my-standalone
Every 3.0s: kubectl get sts -n demo my-standalone suaas-appscode: Wed Jul 1 17:48:52 2020
NAME READY AGE
my-standalone 1/1 3m36s
$ watch -n 3 kubectl get pod -n demo my-standalone-0
Every 3.0s: kubectl get pod -n demo my-standalone-0 suaas-appscode: Wed Jul 1 17:50:18 2020
NAME READY STATUS RESTARTS AGE
my-standalone-0 1/1 Running 0 5m1s
Let’s check the above Pod containers resources,
$ kubectl get pod -n demo my-standalone-0 -o json | jq '.spec.containers[].resources'
{}
You can see the Pod has empty resources that mean the scheduler will choose a random node to place the container of the Pod on by default
We are ready to apply a horizontal scale on this standalone database.
Vertical Scaling
Here, we are going to update the resources of the standalone 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: my-scale-standalone
namespace: demo
spec:
type: VerticalScaling
databaseRef:
name: my-standalone
verticalScaling:
postgres:
requests:
memory: "1200Mi"
cpu: "0.7"
limits:
memory: "1200Mi"
cpu: "0.7"
Here,
spec.databaseRef.name specifies that we are performing operation on my-group Postgres database.spec.type specifies that we are performing VerticalScaling on our database.spec.VerticalScaling.postgres specifies 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/v2021.11.24/docs/guides/postgres/scaling/vertical-scaling/standalone/yamls/my-scale-standalone.yaml
postgresopsrequest.ops.kubedb.com/my-scale-standalone created
Verify Postgres Standalone resources updated successfully:
If everything goes well, KubeDB enterprise operator will update the resources of the StatefulSet’s Pod containers. After a successful scaling process is done, the KubeDB enterprise operator updates the resources of the Postgres object.
First, we will wait for PostgresOpsRequest to be successful. Run the following command to watch MySQlOpsRequest cr,
$ watch -n 3 kubectl get myops -n demo my-scale-standalone
Every 3.0s: kubectl get myops -n demo my-sc... suaas-appscode: Wed Aug 12 17:21:42 2020
NAME TYPE STATUS AGE
my-scale-standalone VerticalScaling Successful 2m15s
We can see from the above output that the PostgresOpsRequest has succeeded. If we describe the PostgresOpsRequest, we shall see that the standalone resources are updated.
$ kubectl describe myops -n demo my-scale-standalone
Name: my-scale-standalone
Namespace: demo
Labels: <none>
Annotations: <none>
API Version: ops.kubedb.com/v1alpha1
Kind: PostgresOpsRequest
Metadata:
Creation Timestamp: 2021-03-10T10:42:05Z
Generation: 2
Operation: Update
Time: 2021-03-10T10:42:05Z
API Version: ops.kubedb.com/v1alpha1
Fields Type: FieldsV1
Manager: kubedb-enterprise
Operation: Update
Time: 2021-03-10T10:42:31Z
Resource Version: 1080528
Self Link: /apis/ops.kubedb.com/v1alpha1/namespaces/demo/postgresopsrequests/my-scale-standalone
UID: f6371eeb-b6e3-4d9b-ba15-0dbc6a92385c
Spec:
Database Ref:
Name: my-standalone
Stateful Set Ordinal: 0
Type: VerticalScaling
Vertical Scaling:
Mysql:
Limits:
Cpu: 0.7
Memory: 1200Mi
Requests:
Cpu: 0.7
Memory: 1200Mi
Status:
Conditions:
Last Transition Time: 2021-03-10T10:42:05Z
Message: Controller has started to Progress the PostgresOpsRequest: demo/my-scale-standalone
Observed Generation: 2
Reason: OpsRequestProgressingStarted
Status: True
Type: Progressing
Last Transition Time: 2021-03-10T10:42:05Z
Message: Vertical scaling started in Postgres: demo/my-standalone for PostgresOpsRequest: my-scale-standalone
Observed Generation: 2
Reason: VerticalScalingStarted
Status: True
Type: Scaling
Last Transition Time: 2021-03-10T10:42:30Z
Message: Vertical scaling performed successfully in Postgres: demo/my-standalone for PostgresOpsRequest: my-scale-standalone
Observed Generation: 2
Reason: SuccessfullyPerformedVerticalScaling
Status: True
Type: VerticalScaling
Last Transition Time: 2021-03-10T10:42:31Z
Message: Controller has successfully scaled the Postgres demo/my-scale-standalone
Observed Generation: 2
Reason: OpsRequestProcessedSuccessfully
Status: True
Type: Successful
Observed Generation: 3
Phase: Successful
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Starting 40s KubeDB Enterprise Operator Start processing for PostgresOpsRequest: demo/my-scale-standalone
Normal Starting 40s KubeDB Enterprise Operator Pausing Postgres databse: demo/my-standalone
Normal Successful 40s KubeDB Enterprise Operator Successfully paused Postgres database: demo/my-standalone for PostgresOpsRequest: my-scale-standalone
Normal Starting 40s KubeDB Enterprise Operator Vertical scaling started in Postgres: demo/my-standalone for PostgresOpsRequest: my-scale-standalone
Normal Starting 35s KubeDB Enterprise Operator Restarting Pod (master): demo/my-standalone-0
Normal Successful 15s KubeDB Enterprise Operator Vertical scaling performed successfully in Postgres: demo/my-standalone for PostgresOpsRequest: my-scale-standalone
Normal Starting 14s KubeDB Enterprise Operator Resuming Postgres database: demo/my-standalone
Normal Successful 14s KubeDB Enterprise Operator Successfully resumed Postgres database: demo/my-standalone
Normal Successful 14s KubeDB Enterprise Operator Controller has Successfully scaled the Postgres database: demo/my-standalone
Now, we are going to verify whether the resources of the standalone has updated to meet up the desired state, Let’s check,
$ kubectl get pod -n demo my-standalone-0 -o json | jq '.spec.containers[].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 standalone.
Cleaning Up
To clean up the Kubernetes resources created by this tutorial, run:
kubectl delete my -n demo my-standalone
kubectl delete myops -n demo my-scale-standalone
