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Vertical Scale MongoDB Standalone
This guide will show you how to use KubeDB Ops-manager operator to update the resources of a MongoDB standalone database.
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 Provisioner and Ops-manager 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/examples/mongodb directory of kubedb/docs repository.
Apply Vertical Scaling on Standalone
Here, we are going to deploy a MongoDB standalone using a supported version by KubeDB operator. Then we are going to apply vertical scaling on it.
Prepare MongoDB Standalone Database
Now, we are going to deploy a MongoDB standalone database with version 4.2.3.
Deploy MongoDB standalone
In this section, we are going to deploy a MongoDB standalone database. Then, in the next section we will update the resources of the database using MongoDBOpsRequest CRD. Below is the YAML of the MongoDB CR that we are going to create,
apiVersion: kubedb.com/v1alpha2
kind: MongoDB
metadata:
name: mg-standalone
namespace: demo
spec:
version: "4.2.3"
storageType: Durable
storage:
storageClassName: "standard"
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
Let’s create the MongoDB CR we have shown above,
$ kubectl create -f https://github.com/kubedb/docs/raw/v2023.02.28/docs/examples/mongodb/scaling/mg-standalone.yaml
mongodb.kubedb.com/mg-standalone created
Now, wait until mg-standalone has status Ready. i.e,
$ kubectl get mg -n demo
NAME VERSION STATUS AGE
mg-standalone 4.2.3 Ready 5m56s
Let’s check the Pod containers resources,
$ kubectl get pod -n demo mg-standalone-0 -o json | jq '.spec.containers[].resources'
{
"limits": {
"cpu": "500m",
"memory": "1Gi"
},
"requests": {
"cpu": "500m",
"memory": "1Gi"
}
}
You can see the Pod has default resources which is assigned by the Kubedb operator.
We are now ready to apply the MongoDBOpsRequest CR to update the resources of this database.
Vertical Scaling
Here, we are going to update the resources of the standalone database to meet the desired resources after scaling.
Create MongoDBOpsRequest
In order to update the resources of the database, we have to create a MongoDBOpsRequest CR with our desired resources. Below is the YAML of the MongoDBOpsRequest CR that we are going to create,
apiVersion: ops.kubedb.com/v1alpha1
kind: MongoDBOpsRequest
metadata:
name: mops-vscale-standalone
namespace: demo
spec:
type: VerticalScaling
databaseRef:
name: mg-standalone
verticalScaling:
standalone:
requests:
memory: "2Gi"
cpu: "1"
limits:
memory: "2Gi"
cpu: "1"
readinessCriteria:
oplogMaxLagSeconds: 20
objectsCountDiffPercentage: 10
timeout: 5m
apply: IfReady
Here,
spec.databaseRef.name specifies that we are performing vertical scaling operation on mops-vscale-standalone database.spec.type specifies that we are performing VerticalScaling on our database.spec.VerticalScaling.standalone specifies the desired resources after scaling.- Have a look here on the respective sections to understand the
readinessCriteria, timeout & apply fields.
Let’s create the MongoDBOpsRequest CR we have shown above,
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2023.02.28/docs/examples/mongodb/scaling/vertical-scaling/mops-vscale-standalone.yaml
mongodbopsrequest.ops.kubedb.com/mops-vscale-standalone created
Verify MongoDB Standalone resources updated successfully
If everything goes well, KubeDB Ops-manager operator will update the resources of MongoDB object and related StatefulSets and Pods.
Let’s wait for MongoDBOpsRequest to be Successful. Run the following command to watch MongoDBOpsRequest CR,
$ kubectl get mongodbopsrequest -n demo
Every 2.0s: kubectl get mongodbopsrequest -n demo
NAME TYPE STATUS AGE
mops-vscale-standalone VerticalScaling Successful 108s
We can see from the above output that the MongoDBOpsRequest has succeeded. If we describe the MongoDBOpsRequest we will get an overview of the steps that were followed to scale the database.
$ kubectl describe mongodbopsrequest -n demo mops-vscale-standalone
Name: mops-vscale-standalone
Namespace: demo
Labels: <none>
Annotations: <none>
API Version: ops.kubedb.com/v1alpha1
Kind: MongoDBOpsRequest
Metadata:
Creation Timestamp: 2022-10-26T10:54:01Z
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:apply:
f:databaseRef:
f:readinessCriteria:
.:
f:objectsCountDiffPercentage:
f:oplogMaxLagSeconds:
f:timeout:
f:type:
f:verticalScaling:
.:
f:standalone:
.:
f:limits:
.:
f:cpu:
f:memory:
f:requests:
.:
f:cpu:
f:memory:
Manager: kubectl-client-side-apply
Operation: Update
Time: 2022-10-26T10:54:01Z
API Version: ops.kubedb.com/v1alpha1
Fields Type: FieldsV1
fieldsV1:
f:status:
.:
f:conditions:
f:observedGeneration:
f:phase:
Manager: kubedb-ops-manager
Operation: Update
Subresource: status
Time: 2022-10-26T10:54:52Z
Resource Version: 613933
UID: c3bf9c3d-cf96-49ae-877f-a895e0b1d280
Spec:
Apply: IfReady
Database Ref:
Name: mg-standalone
Readiness Criteria:
Objects Count Diff Percentage: 10
Oplog Max Lag Seconds: 20
Timeout: 5m
Type: VerticalScaling
Vertical Scaling:
Standalone:
Limits:
Cpu: 1
Memory: 2Gi
Requests:
Cpu: 1
Memory: 2Gi
Status:
Conditions:
Last Transition Time: 2022-10-26T10:54:21Z
Message: MongoDB ops request is vertically scaling database
Observed Generation: 1
Reason: VerticalScaling
Status: True
Type: VerticalScaling
Last Transition Time: 2022-10-26T10:54:51Z
Message: Successfully Vertically Scaled Standalone Resources
Observed Generation: 1
Reason: UpdateStandaloneResources
Status: True
Type: UpdateStandaloneResources
Last Transition Time: 2022-10-26T10:54:52Z
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 34s KubeDB Ops-manager Operator Pausing MongoDB demo/mg-standalone
Normal PauseDatabase 34s KubeDB Ops-manager Operator Successfully paused MongoDB demo/mg-standalone
Normal Starting 34s KubeDB Ops-manager Operator Updating Resources of StatefulSet: mg-standalone
Normal UpdateStandaloneResources 34s KubeDB Ops-manager Operator Successfully updated standalone Resources
Normal Starting 34s KubeDB Ops-manager Operator Updating Resources of StatefulSet: mg-standalone
Normal UpdateStandaloneResources 34s KubeDB Ops-manager Operator Successfully updated standalone Resources
Normal UpdateStandaloneResources 4s KubeDB Ops-manager Operator Successfully Vertically Scaled Standalone Resources
Normal UpdateStandaloneResources 4s KubeDB Ops-manager Operator Successfully Vertically Scaled Standalone Resources
Normal ResumeDatabase 4s KubeDB Ops-manager Operator Resuming MongoDB demo/mg-standalone
Normal ResumeDatabase 3s KubeDB Ops-manager Operator Successfully resumed MongoDB demo/mg-standalone
Normal Successful 3s KubeDB Ops-manager Operator Successfully Vertically Scaled Database
Now, we are going to verify from the Pod yaml whether the resources of the standalone database has updated to meet up the desired state, Let’s check,
$ kubectl get pod -n demo mg-standalone-0 -o json | jq '.spec.containers[].resources'
{
"limits": {
"cpu": "1",
"memory": "2Gi"
},
"requests": {
"cpu": "1",
"memory": "2Gi"
}
}
The above output verifies that we have successfully scaled up the resources of the MongoDB standalone database.
Cleaning Up
To clean up the Kubernetes resources created by this tutorial, run:
kubectl delete mg -n demo mg-standalone
kubectl delete mongodbopsrequest -n demo mops-vscale-standalone
