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 and the streaming platform Kafka. You can find the guides to all the supported databases in KubeDB . In this tutorial we will show Horizontal scaling of MySQL cluster in Google Kubernetes Engine (GKE). We will cover the following steps:
- Install KubeDB
- Deploy MySQL Cluster
- Read/Write Sample Data
- Horizontal Scaling of MySQL 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 v2024.3.16 v2024.3.16 KubeDB by AppsCode - Production ready databases...
appscode/kubedb-autoscaler v0.29.0 v0.29.0 KubeDB Autoscaler by AppsCode - Autoscale KubeD...
appscode/kubedb-catalog v2024.3.16 v2024.3.16 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 v0.0.8 v0.0.8 KubeDB CRD Manager by AppsCode
appscode/kubedb-crds v2024.3.16 v2024.3.16 KubeDB Custom Resource Definitions
appscode/kubedb-dashboard v0.20.0 v0.20.0 KubeDB Dashboard by AppsCode
appscode/kubedb-enterprise v0.11.2 v0.11.2 KubeDB Enterprise by AppsCode - Enterprise feat...
appscode/kubedb-grafana-dashboards v2024.3.16 v2024.3.16 A Helm chart for kubedb-grafana-dashboards by A...
appscode/kubedb-kubestash-catalog v2024.3.16 v2024.3.16 KubeStash Catalog by AppsCode - Catalog of Kube...
appscode/kubedb-metrics v2024.3.16 v2024.3.16 KubeDB State Metrics
appscode/kubedb-one v2023.12.28 v2023.12.28 KubeDB and Stash by AppsCode - Production ready...
appscode/kubedb-ops-manager v0.31.0 v0.31.0 KubeDB Ops Manager by AppsCode - Enterprise fea...
appscode/kubedb-opscenter v2024.3.16 v2024.3.16 KubeDB Opscenter by AppsCode
appscode/kubedb-provider-aws v2024.3.16 v0.6.0 A Helm chart for KubeDB AWS Provider for Crossp...
appscode/kubedb-provider-azure v2024.3.16 v0.6.0 A Helm chart for KubeDB Azure Provider for Cros...
appscode/kubedb-provider-gcp v2024.3.16 v0.6.0 A Helm chart for KubeDB GCP Provider for Crossp...
appscode/kubedb-provisioner v0.44.0 v0.44.0 KubeDB Provisioner by AppsCode - Community feat...
appscode/kubedb-schema-manager v0.20.0 v0.20.0 KubeDB Schema Manager by AppsCode
appscode/kubedb-ui v2024.2.13 0.6.4 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 v0.20.0 v0.20.0 KubeDB Webhook Server by AppsCode
$ helm install kubedb oci://ghcr.io/appscode-charts/kubedb \
--version v2024.3.16 \
--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-6bc4dfb8b4-xxp46 1/1 Running 0 2m31s
kubedb kubedb-kubedb-ops-manager-84b4989cc4-fhd65 1/1 Running 0 2m31s
kubedb kubedb-kubedb-provisioner-5f4cdf797b-qmz4c 1/1 Running 0 2m31s
kubedb kubedb-kubedb-webhook-server-6bf76df97-wm4vz 1/1 Running 0 2m31s
kubedb kubedb-petset-operator-5d94b4ddb8-tfvbq 1/1 Running 0 2m31s
kubedb kubedb-petset-webhook-server-67794c9fcd-phl6m 2/2 Running 0 2m31s
kubedb kubedb-sidekick-5dc87959b7-fr2sg 1/1 Running 0 2m31s
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 2024-03-25T06:36:43Z
connectors.kafka.kubedb.com 2024-03-25T06:36:43Z
druidversions.catalog.kubedb.com 2024-03-25T06:36:09Z
elasticsearchautoscalers.autoscaling.kubedb.com 2024-03-25T06:36:40Z
elasticsearchdashboards.elasticsearch.kubedb.com 2024-03-25T06:36:40Z
elasticsearches.kubedb.com 2024-03-25T06:36:40Z
elasticsearchopsrequests.ops.kubedb.com 2024-03-25T06:36:40Z
elasticsearchversions.catalog.kubedb.com 2024-03-25T06:36:09Z
etcdversions.catalog.kubedb.com 2024-03-25T06:36:09Z
ferretdbversions.catalog.kubedb.com 2024-03-25T06:36:09Z
kafkaautoscalers.autoscaling.kubedb.com 2024-03-25T06:36:43Z
kafkaconnectorversions.catalog.kubedb.com 2024-03-25T06:36:09Z
kafkaopsrequests.ops.kubedb.com 2024-03-25T06:36:43Z
kafkas.kubedb.com 2024-03-25T06:36:43Z
kafkaversions.catalog.kubedb.com 2024-03-25T06:36:09Z
mariadbarchivers.archiver.kubedb.com 2024-03-25T06:36:47Z
mariadbautoscalers.autoscaling.kubedb.com 2024-03-25T06:36:47Z
mariadbdatabases.schema.kubedb.com 2024-03-25T06:36:47Z
mariadbopsrequests.ops.kubedb.com 2024-03-25T06:36:47Z
mariadbs.kubedb.com 2024-03-25T06:36:47Z
mariadbversions.catalog.kubedb.com 2024-03-25T06:36:09Z
memcachedversions.catalog.kubedb.com 2024-03-25T06:36:09Z
mongodbarchivers.archiver.kubedb.com 2024-03-25T06:36:50Z
mongodbautoscalers.autoscaling.kubedb.com 2024-03-25T06:36:50Z
mongodbdatabases.schema.kubedb.com 2024-03-25T06:36:50Z
mongodbopsrequests.ops.kubedb.com 2024-03-25T06:36:50Z
mongodbs.kubedb.com 2024-03-25T06:36:50Z
mongodbversions.catalog.kubedb.com 2024-03-25T06:36:09Z
mysqlarchivers.archiver.kubedb.com 2024-03-25T06:36:54Z
mysqlautoscalers.autoscaling.kubedb.com 2024-03-25T06:36:54Z
mysqldatabases.schema.kubedb.com 2024-03-25T06:36:54Z
mysqlopsrequests.ops.kubedb.com 2024-03-25T06:36:54Z
mysqls.kubedb.com 2024-03-25T06:36:54Z
mysqlversions.catalog.kubedb.com 2024-03-25T06:36:09Z
perconaxtradbversions.catalog.kubedb.com 2024-03-25T06:36:09Z
pgbouncerversions.catalog.kubedb.com 2024-03-25T06:36:09Z
pgpoolversions.catalog.kubedb.com 2024-03-25T06:36:09Z
postgresarchivers.archiver.kubedb.com 2024-03-25T06:36:57Z
postgresautoscalers.autoscaling.kubedb.com 2024-03-25T06:36:57Z
postgresdatabases.schema.kubedb.com 2024-03-25T06:36:57Z
postgreses.kubedb.com 2024-03-25T06:36:57Z
postgresopsrequests.ops.kubedb.com 2024-03-25T06:36:57Z
postgresversions.catalog.kubedb.com 2024-03-25T06:36:09Z
proxysqlversions.catalog.kubedb.com 2024-03-25T06:36:09Z
publishers.postgres.kubedb.com 2024-03-25T06:36:57Z
rabbitmqversions.catalog.kubedb.com 2024-03-25T06:36:09Z
redisautoscalers.autoscaling.kubedb.com 2024-03-25T06:37:01Z
redises.kubedb.com 2024-03-25T06:37:01Z
redisopsrequests.ops.kubedb.com 2024-03-25T06:37:01Z
redissentinelautoscalers.autoscaling.kubedb.com 2024-03-25T06:37:01Z
redissentinelopsrequests.ops.kubedb.com 2024-03-25T06:37:01Z
redissentinels.kubedb.com 2024-03-25T06:37:01Z
redisversions.catalog.kubedb.com 2024-03-25T06:36:09Z
singlestoreversions.catalog.kubedb.com 2024-03-25T06:36:09Z
solrversions.catalog.kubedb.com 2024-03-25T06:36:09Z
subscribers.postgres.kubedb.com 2024-03-25T06:36:57Z
zookeeperversions.catalog.kubedb.com 2024-03-25T06:36:09Z
Deploy MySQL Cluster
We are going to Deploy MySQL 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 MySQL CR we are going to use:
apiVersion: kubedb.com/v1alpha2
kind: MySQL
metadata:
name: mysql-cluster
namespace: demo
spec:
version: "8.2.0"
replicas: 3
topology:
mode: GroupReplication
storageType: Durable
storage:
storageClassName: "standard"
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
terminationPolicy: WipeOut
Let’s save this yaml configuration into mysql-cluster.yaml
Then create the above MySQL CR
$ kubectl apply -f mysql-cluster.yaml
mysql.kubedb.com/mysql-cluster created
In this yaml,
- In this yaml we can see in the
spec.versionfield specifies the version of MySQL. Here, we are using MySQL8.2.0. You can list the KubeDB supported versions of MySQL by running$ kubectl get mysqlversionscommand. spec.topologyrepresents the clustering configuration for MySQL.spec.topology.modespecifies the mode for MySQL cluster. Here we have usedGroupReplication.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 MySQL object is deployed, you will see that the following objects are created:
$ kubectl get all -n demo
NAME READY STATUS RESTARTS AGE
pod/mysql-cluster-0 2/2 Running 0 3m15s
pod/mysql-cluster-1 2/2 Running 0 2m14s
pod/mysql-cluster-2 2/2 Running 0 2m6s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/mysql-cluster ClusterIP 10.96.236.191 <none> 3306/TCP 3m19s
service/mysql-cluster-pods ClusterIP None <none> 3306/TCP 3m19s
service/mysql-cluster-standby ClusterIP 10.96.193.152 <none> 3306/TCP 3m19s
NAME READY AGE
statefulset.apps/mysql-cluster 3/3 3m15s
NAME TYPE VERSION AGE
appbinding.appcatalog.appscode.com/mysql-cluster kubedb.com/mysql 8.2.0 3m15s
NAME VERSION STATUS AGE
mysql.kubedb.com/mysql-cluster 8.2.0 Ready 3m19s
Let’s check if the database is ready to use,
$ kubectl get mysql -n demo mysql-cluster
NAME VERSION STATUS AGE
mysql-cluster 8.2.0 Ready 3m39s
We have successfully deployed MySQL cluster in GKE. 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 mysql-cluster that we have deployed. Let’s check them using the following commands,
$ kubectl get secret -n demo -l=app.kubernetes.io/instance=mysql-cluster
NAME TYPE DATA AGE
mysql-cluster-auth kubernetes.io/basic-auth 2 4m5s
$ kubectl get service -n demo -l=app.kubernetes.io/instance=mysql-cluster
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
mysql-cluster ClusterIP 10.96.236.191 <none> 3306/TCP 4m20s
mysql-cluster-pods ClusterIP None <none> 3306/TCP 4m20s
mysql-cluster-standby ClusterIP 10.96.193.152 <none> 3306/TCP 4m20s
Now, we are going to use mysql-cluster-auth to get the credentials.
$ kubectl get secrets -n demo mysql-cluster-auth -o jsonpath='{.data.username}' | base64 -d
root
$ kubectl get secrets -n demo mysql-cluster-auth -o jsonpath='{.data.password}' | base64 -d
Cdzg!uXI3.r7BUMF
Insert Sample Data
In this section, we are going to login into our MySQL database pod and insert some sample data.
$ kubectl exec -it mysql-cluster-0 -n demo -c mysql -- bash
bash-4.4$ mysql --user=root --password='Cdzg!uXI3.r7BUMF'
Welcome to the MySQL monitor. Commands end with ; or \g.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> CREATE DATABASE Music;
Query OK, 1 row affected (0.00 sec)
mysql> CREATE TABLE Music.Artist (id INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY, Name VARCHAR(50), Song VARCHAR(50));
Query OK, 0 rows affected, 1 warning (0.01 sec)
mysql> INSERT INTO Music.Artist (Name, Song) VALUES ("Avicii", "The Nights");
Query OK, 1 row affected (0.00 sec)
mysql> SELECT * FROM Music.Artist;
+----+--------+------------+
| id | Name | Song |
+----+--------+------------+
| 1 | Avicii | The Nights |
+----+--------+------------+
1 row in set (0.00 sec)
mysql> exit
Bye
We’ve successfully inserted some sample data to our database. More information about Deploy & Manage MySQL on Kubernetes can be found in Kubernetes MySQL
Horizontal Scaling of MySQL Cluster
Horizontal Scale Up
Here, we are going to scale up the replicas of the MySQL cluster replicaset to meet the desired number of replicas after scaling. Before applying Horizontal Scaling, let’s check the current number of replicas,
$ kubectl get mysql -n demo mysql-cluster -o json | jq '.spec.replicas'
3
Create MySQLOpsRequest
In order to scale up, we have to create a MySQLOpsRequest CR with our desired replicas. Let’s create it using this following yaml,
apiVersion: ops.kubedb.com/v1alpha1
kind: MySQLOpsRequest
metadata:
name: horizontal-scale-up
namespace: demo
spec:
type: HorizontalScaling
databaseRef:
name: mysql-cluster
horizontalScaling:
member: 5
In this yaml,
spec.databaseRef.namespecifies that we are performing horizontal scaling operation onmysql-clusterdatabase.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
mysqlopsrequest.ops.kubedb.com/horizontal-scale-up created
Let’s wait for MySQLOpsRequest STATUS to be Successful. Run the following command to watch MySQLOpsRequest CR,
$ watch kubectl get mysqlopsrequest -n demo
NAME TYPE STATUS AGE
horizontal-scale-up HorizontalScaling Successful 2m47s
From the above output we can see that the MySQLOpsRequest has succeeded. Now, we are going to verify the number of replicas,
$ kubectl get mysql -n demo mysql-cluster -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 MySQL 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 MySQLOpsRequest
In order to scale down, again we need to create a MySQLOpsRequest CR with our desired replicas. Let’s create it using this following yaml,
apiVersion: ops.kubedb.com/v1alpha1
kind: MySQLOpsRequest
metadata:
name: horizontal-scale-down
namespace: demo
spec:
type: HorizontalScaling
databaseRef:
name: mysql-cluster
horizontalScaling:
member: 3
In this yaml,
spec.databaseRef.namespecifies that we are performing horizontal scaling operation onmysql-clusterdatabase.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
mysqlopsrequest.ops.kubedb.com/horizontal-scale-down created
Let’s wait for MySQLOpsRequest STATUS to be Successful. Run the following command to watch MySQLOpsRequest CR,
$ watch kubectl get mysqlopsrequest -n demo
NAME TYPE STATUS AGE
horizontal-scale-down HorizontalScaling Successful 2m5s
From the above output we can see that the MySQLOpsRequest has succeeded. Now, we are going to verify the number of replicas,
$ kubectl get mysql -n demo mysql-cluster -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 MySQL cluster.
If you want to learn more about Production-Grade MySQL on Kubernetes you can have a look into that playlist below:
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More about MySQL on Kubernetes
If you have found a bug with KubeDB or want to request for new features, please file an issue .