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, Percona XtraDB, and Memcached. Additionally, KubeDB also supports ProxySQL, PgBouncer, Pgpool 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 MongoDB cluster in Azure Kubernetes Service (AKS). We will cover the following steps:
- Install KubeDB
- Deploy MongoDB Cluster
- Read/Write Sample Data
- Horizontal Scaling of MongoDB 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 search repo appscode/kubedb
NAME CHART VERSION APP VERSION DESCRIPTION
appscode/kubedb v2024.4.27 v2024.4.27 KubeDB by AppsCode - Production ready databases...
appscode/kubedb-autoscaler v0.30.0 v0.30.0 KubeDB Autoscaler by AppsCode - Autoscale KubeD...
appscode/kubedb-catalog v2024.4.27 v2024.4.27 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 v0.0.9 v0.0.9 KubeDB CRD Manager by AppsCode
appscode/kubedb-crds v2024.4.27 v2024.4.27 KubeDB Custom Resource Definitions
appscode/kubedb-dashboard v0.21.0 v0.21.0 KubeDB Dashboard by AppsCode
appscode/kubedb-enterprise v0.11.2 v0.11.2 KubeDB Enterprise by AppsCode - Enterprise feat...
appscode/kubedb-grafana-dashboards v2024.4.27 v2024.4.27 A Helm chart for kubedb-grafana-dashboards by A...
appscode/kubedb-kubestash-catalog v2024.4.27 v2024.4.27 KubeStash Catalog by AppsCode - Catalog of Kube...
appscode/kubedb-metrics v2024.4.27 v2024.4.27 KubeDB State Metrics
appscode/kubedb-one v2023.12.28 v2023.12.28 KubeDB and Stash by AppsCode - Production ready...
appscode/kubedb-ops-manager v0.32.0 v0.32.1 KubeDB Ops Manager by AppsCode - Enterprise fea...
appscode/kubedb-opscenter v2024.4.27 v2024.4.27 KubeDB Opscenter by AppsCode
appscode/kubedb-provider-aws v2024.4.27 v0.7.0 A Helm chart for KubeDB AWS Provider for Crossp...
appscode/kubedb-provider-azure v2024.4.27 v0.7.0 A Helm chart for KubeDB Azure Provider for Cros...
appscode/kubedb-provider-gcp v2024.4.27 v0.7.0 A Helm chart for KubeDB GCP Provider for Crossp...
appscode/kubedb-provisioner v0.45.0 v0.45.1 KubeDB Provisioner by AppsCode - Community feat...
appscode/kubedb-schema-manager v0.21.0 v0.21.0 KubeDB Schema Manager by AppsCode
appscode/kubedb-ui v2024.5.3 0.6.6 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 v0.21.0 v0.21.1 KubeDB Webhook Server by AppsCode
$ helm install kubedb oci://ghcr.io/appscode-charts/kubedb \
--version v2024.4.27 \
--namespace kubedb --create-namespace \
--set-file global.license=/path/to/the/license.txt \
--wait --burst-limit=10000 --debug
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-9f945c8dc-rmrkg 1/1 Running 0 3m34s
kubedb kubedb-kubedb-ops-manager-7dcc797544-2lv8s 1/1 Running 0 3m34s
kubedb kubedb-kubedb-provisioner-ddb87568d-sw7pn 1/1 Running 0 3m34s
kubedb kubedb-kubedb-webhook-server-66fd46fb57-4w5f9 1/1 Running 0 3m34s
kubedb kubedb-petset-operator-5d94b4ddb8-kg2ql 1/1 Running 0 3m34s
kubedb kubedb-petset-webhook-server-d7887fd67-hctkb 2/2 Running 0 3m34s
kubedb kubedb-sidekick-5d9947bd9-q9lkj 1/1 Running 0 3m34s
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
connectclusters.kafka.kubedb.com 2024-05-15T06:45:16Z
connectors.kafka.kubedb.com 2024-05-15T06:45:16Z
druidversions.catalog.kubedb.com 2024-05-15T06:40:34Z
elasticsearchautoscalers.autoscaling.kubedb.com 2024-05-15T06:45:13Z
elasticsearchdashboards.elasticsearch.kubedb.com 2024-05-15T06:45:13Z
elasticsearches.kubedb.com 2024-05-15T06:45:13Z
elasticsearchopsrequests.ops.kubedb.com 2024-05-15T06:45:13Z
elasticsearchversions.catalog.kubedb.com 2024-05-15T06:40:34Z
etcdversions.catalog.kubedb.com 2024-05-15T06:40:35Z
ferretdbversions.catalog.kubedb.com 2024-05-15T06:40:35Z
kafkaautoscalers.autoscaling.kubedb.com 2024-05-15T06:45:16Z
kafkaconnectorversions.catalog.kubedb.com 2024-05-15T06:40:35Z
kafkaopsrequests.ops.kubedb.com 2024-05-15T06:45:16Z
kafkas.kubedb.com 2024-05-15T06:45:16Z
kafkaversions.catalog.kubedb.com 2024-05-15T06:40:35Z
mariadbarchivers.archiver.kubedb.com 2024-05-15T06:45:19Z
mariadbautoscalers.autoscaling.kubedb.com 2024-05-15T06:45:19Z
mariadbdatabases.schema.kubedb.com 2024-05-15T06:45:19Z
mariadbopsrequests.ops.kubedb.com 2024-05-15T06:45:19Z
mariadbs.kubedb.com 2024-05-15T06:45:19Z
mariadbversions.catalog.kubedb.com 2024-05-15T06:40:35Z
memcachedversions.catalog.kubedb.com 2024-05-15T06:40:35Z
mongodbarchivers.archiver.kubedb.com 2024-05-15T06:45:23Z
mongodbautoscalers.autoscaling.kubedb.com 2024-05-15T06:45:23Z
mongodbdatabases.schema.kubedb.com 2024-05-15T06:45:23Z
mongodbopsrequests.ops.kubedb.com 2024-05-15T06:45:23Z
mongodbs.kubedb.com 2024-05-15T06:45:22Z
mongodbversions.catalog.kubedb.com 2024-05-15T06:40:35Z
mssqlserverversions.catalog.kubedb.com 2024-05-15T06:40:35Z
mysqlarchivers.archiver.kubedb.com 2024-05-15T06:45:26Z
mysqlautoscalers.autoscaling.kubedb.com 2024-05-15T06:45:26Z
mysqldatabases.schema.kubedb.com 2024-05-15T06:45:26Z
mysqlopsrequests.ops.kubedb.com 2024-05-15T06:45:26Z
mysqls.kubedb.com 2024-05-15T06:45:26Z
mysqlversions.catalog.kubedb.com 2024-05-15T06:40:35Z
perconaxtradbversions.catalog.kubedb.com 2024-05-15T06:40:35Z
pgbouncerversions.catalog.kubedb.com 2024-05-15T06:40:35Z
pgpoolversions.catalog.kubedb.com 2024-05-15T06:40:35Z
postgresarchivers.archiver.kubedb.com 2024-05-15T06:45:29Z
postgresautoscalers.autoscaling.kubedb.com 2024-05-15T06:45:29Z
postgresdatabases.schema.kubedb.com 2024-05-15T06:45:29Z
postgreses.kubedb.com 2024-05-15T06:45:29Z
postgresopsrequests.ops.kubedb.com 2024-05-15T06:45:29Z
postgresversions.catalog.kubedb.com 2024-05-15T06:40:35Z
proxysqlversions.catalog.kubedb.com 2024-05-15T06:40:35Z
publishers.postgres.kubedb.com 2024-05-15T06:45:30Z
rabbitmqversions.catalog.kubedb.com 2024-05-15T06:40:35Z
redisautoscalers.autoscaling.kubedb.com 2024-05-15T06:45:33Z
redises.kubedb.com 2024-05-15T06:45:33Z
redisopsrequests.ops.kubedb.com 2024-05-15T06:45:33Z
redissentinelautoscalers.autoscaling.kubedb.com 2024-05-15T06:45:33Z
redissentinelopsrequests.ops.kubedb.com 2024-05-15T06:45:33Z
redissentinels.kubedb.com 2024-05-15T06:45:33Z
redisversions.catalog.kubedb.com 2024-05-15T06:40:35Z
singlestoreversions.catalog.kubedb.com 2024-05-15T06:40:35Z
solrversions.catalog.kubedb.com 2024-05-15T06:40:35Z
subscribers.postgres.kubedb.com 2024-05-15T06:45:30Z
zookeeperversions.catalog.kubedb.com 2024-05-15T06:40:35Z
Deploy MongoDB Cluster
We are going to Deploy MongoDB 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 MongoDB CR we are going to use:
apiVersion: kubedb.com/v1alpha2
kind: MongoDB
metadata:
name: mongodb-rs
namespace: demo
spec:
version: "7.0.8"
replicas: 3
replicaSet:
name: rs0
storage:
storageClassName: "default"
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
terminationPolicy: WipeOut
Let’s save this yaml configuration into mongodb-rs.yaml
Then create the above MongoDB CR,
$ kubectl apply -f mongodb-rs.yaml
mongodb.kubedb.com/mongodb-rs created
In this yaml,
- In this yaml we can see in the
spec.versionfield specifies the version of MongoDB. Here, we are using MongoDB7.0.8. You can list the KubeDB supported versions of MongoDB by running$ kubectl get mongodbversionscommand. spec.replicasdenotes the number of members inrs0mongodb replicaset.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 MongoDB object is deployed, you will see that the following objects are created:
$ kubectl get all -n demo
NAME READY STATUS RESTARTS AGE
pod/mongodb-rs-0 2/2 Running 0 7m31s
pod/mongodb-rs-1 2/2 Running 0 3m3s
pod/mongodb-rs-2 2/2 Running 0 2m35s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/mongodb-rs ClusterIP 10.96.151.68 <none> 27017/TCP 7m45s
service/mongodb-rs-pods ClusterIP None <none> 27017/TCP 7m45s
NAME READY AGE
statefulset.apps/mongodb-rs 3/3 7m31s
NAME TYPE VERSION AGE
appbinding.appcatalog.appscode.com/mongodb-rs kubedb.com/mongodb 7.0.8 7m17s
NAME VERSION STATUS AGE
mongodb.kubedb.com/mongodb-rs 7.0.8 Ready 7m45s
Let’s check if the database is ready to use,
$ kubectl get mongodb -n demo mongodb-rs
NAME VERSION STATUS AGE
mongodb-rs 7.0.8 Ready 8m3s
We have successfully deployed MongoDB 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 mongodb that we have deployed. Let’s check them using the following commands,
$ kubectl get secret -n demo -l=app.kubernetes.io/instance=mongodb-rs
NAME TYPE DATA AGE
mongodb-rs-auth kubernetes.io/basic-auth 2 9m42s
mongodb-rs-key Opaque 1 9m42s
$ kubectl get service -n demo -l=app.kubernetes.io/instance=mongodb-rs
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
mongodb-rs ClusterIP 10.96.151.68 <none> 27017/TCP 9m56s
mongodb-rs-pods ClusterIP None <none> 27017/TCP 9m56s
Now, we are going to use mongodb-rs-auth to export credentials.
$ kubectl get secrets -n demo mongodb-rs-auth -o jsonpath='{.data.\username}' | base64 -d
root
$ kubectl get secrets -n demo mongodb-rs-auth -o jsonpath='{.data.\password}' | base64 -d
LRhf)ac41Y_LxE;d
Insert Sample Data
In this section, we are going to login into our MongoDB pod and insert some sample data.
$ kubectl exec -it mongodb-rs-0 -n demo bash
Defaulted container "mongodb" out of: mongodb, replication-mode-detector, copy-config (init)
mongodb@mongodb-rs-0:/$ mongosh admin -u root -p 'LRhf)ac41Y_LxE;d'
Using MongoDB: 7.0.8
Using Mongosh: 2.2.5
For mongosh info see: https://docs.mongodb.com/mongodb-shell/
rs0 [direct: primary] admin> show dbs
admin 172.00 KiB
config 344.00 KiB
kubedb-system 40.00 KiB
local 448.00 KiB
rs0 [direct: primary] admin> use musicdb
switched to db musicdb
rs0 [direct: primary] musicdb> db.songs.insert({"name":"The Nights"});
{
acknowledged: true,
insertedIds: { '0': ObjectId('66472c4464d2c14f2c2202d8') }
}
rs0 [direct: primary] musicdb> db.songs.find().pretty()
[ { _id: ObjectId('66472c4464d2c14f2c2202d8'), name: 'The Nights' } ]
rs0 [direct: primary] musicdb> exit
mongodb@mongodb-rs-0:/$ exit
exit
We’ve successfully inserted some sample data to our database. More information about Deploy & Manage MongoDB on Kubernetes can be found in Kubernetes MongoDB
Horizontal Scaling of MongoDB Cluster
Horizontal Scale Up
Here, we are going to scale up the replicas of the MongoDB cluster replicas to meet the desired number of replicas after scaling. Before applying Horizontal Scaling, let’s check the current number of replicas,
$ kubectl get mongodb -n demo mongodb-rs -o json | jq '.spec.replicas'
3
Create MongoDBOpsRequest
In order to scale up, we have to create a MongoDBOpsRequest CR with our desired replicas. Let’s create it using this following yaml,
apiVersion: ops.kubedb.com/v1alpha1
kind: MongoDBOpsRequest
metadata:
name: horizontal-scale-up
namespace: demo
spec:
type: HorizontalScaling
databaseRef:
name: mongodb-rs
horizontalScaling:
replicas: 5
In this yaml,
spec.databaseRef.namespecifies that we are performing horizontal scaling operation onmongodb-rsdatabase.spec.typespecifies that we are performingHorizontalScalingon our database.spec.horizontalScaling.memberspecifies 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
mongodbopsrequest.ops.kubedb.com/horizontal-scale-up created
Let’s wait for MongoDBOpsRequest STATUS to be Successful. Run the following command to watch MongoDBOpsRequest CR,
$ watch kubectl get mongodbopsrequest -n demo
NAME TYPE STATUS AGE
horizontal-scale-up HorizontalScaling Successful 2m58s
From the above output we can see that the MongoDBOpsRequest has succeeded. Now, we are going to verify the number of replicas,
$ kubectl get mongodb -n demo mongodb-rs -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 MongoDB 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 MongoDBOpsRequest
In order to scale down, again we need to create a MongoDBOpsRequest CR with our desired replicas. Let’s create it using this following yaml,
apiVersion: ops.kubedb.com/v1alpha1
kind: MongoDBOpsRequest
metadata:
name: horizontal-scale-down
namespace: demo
spec:
type: HorizontalScaling
databaseRef:
name: mongodb-rs
horizontalScaling:
replicas: 3
In this yaml,
spec.databaseRef.namespecifies that we are performing horizontal scaling operation onmongodb-rsdatabase.spec.typespecifies that we are performingHorizontalScalingon our database.spec.horizontalScaling.memberspecifies 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
mongodbopsrequest.ops.kubedb.com/horizontal-scale-down created
Let’s wait for MongoDBOpsRequest STATUS to be Successful. Run the following command to watch MongoDBOpsRequest CR,
$ watch kubectl get mongodbopsrequest -n demo
NAME TYPE STATUS AGE
horizontal-scale-down HorizontalScaling Successful 117s
From the above output we can see that the MongoDBOpsRequest has succeeded. Now, we are going to verify the number of replicas,
$ kubectl get mongodb -n demo mongodb-rs -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 MongoDB cluster.
If you want to learn more about Production-Grade MongoDB on Kubernetes you can have a look into that playlist below:
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More about MongoDB on Kubernetes
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