How to Deploy MariaDB on Kubernetes

Introduction

MariaDB is a popular open-source relational database management system that enables storage of data in the form of tables using the Standard Query Language (SQL). Deploying MariaDB on Kubernetes offers multiple benefits such as scalability, high availability, and efficient resource management. Kubernetes offers portability across cloud and on-premises environments, integrates well with CI/CD pipelines, and supports automated backup and recovery making it efficient to run MariaDB deployments.

This article explains how to deploy MariaDB on Kubernetes.

Prerequisites

Before you begin:

• Deploy a Vultr Kubernetes Engine (VKE) cluster with at least three nodes.
• Deploy a Ubuntu instance on Vultr to use as the management workstation.
• Access the workstation using SSH as a non-root user with sudo privileges.
• Install and Configure Kubectl to access the VKE cluster.

Create PV and PVCs

Persistent Volumes (PVs) and Persistent Volume Claims (PVCs) enable the persistent storage of MariaDB data in a cluster. Follow the below steps to create PV and PVCs to use with MariaDB.

1. Create a new mariadb-pv.yaml YAML file for Persistent Volumes.

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   $ nano mariadb-pv.yaml

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2. Add the following contents to the file.

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   apiVersion: v1
   kind: PersistentVolume
   metadata:
       name: mariadb-pv
   spec:
       capacity:
           storage: 10Gi
       accessModes:
           - ReadWriteOnce
       persistentVolumeReclaimPolicy: Retain
       hostPath:
           path: /mnt/data/mariadb

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   Save and close the file.

   The above configuration defines a PersistentVolume (PV) resource mariadb-pv with a 10GB storage capacity. The accessModes field specifies that the volume can be mounted as read-write by a single node at a time. You've set the persistentVolumeReclaimPolicy to Retain which preserves the volume data when the PV is deleted. The hostPath field backs up the volume to your /mnt/data/mariadb workstation directory.

3. Apply the PV configuration to your cluster.

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   $ kubectl apply -f mariadb-pv.yaml

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4. View all PVs in your cluster and verify that the resource is available.

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   $ kubectl get pv mariadb-pv

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   Output:

   NAME         CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM   STORAGECLASS   VOLUMEATTRIBUTESCLASS   REASON   AGE
   mariadb-pv   10Gi       RWO            Retain           Available                          <unset>                          8s

5. Create a new Persistent Volume Claim (PVC) resource file mariadb-pvc.yaml.

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   $ nano mariadb-pvc.yaml

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6. Add the following contents to the file.

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   apiVersion: v1
   kind: PersistentVolumeClaim
   metadata:
       name: mariadb-pvc
   spec:
       accessModes:
           - ReadWriteOnce
       resources:
           requests:
               storage: 10Gi

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   Save and close the file.

   The above configuration creates a new PersistentVolumeClaim (PVC) resource mariadb-pvc with a request for 10 GB of storage. It uses the ReadWriteOnce access mode meaning that the volume can be mounted as read-write by a single node.

7. Apply the PVC configuration to your cluster.

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   $ kubectl apply -f mariadb-pvc.yaml

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8. View the PVC resource and verify that it's state changes to BOUND.

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   $ kubectl get pvc mariadb-pvc

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   Output:

   NAME          STATUS   VOLUME                 CAPACITY   ACCESS MODES   STORAGECLASS          VOLUMEATTRIBUTESCLASS   AGE
   mariadb-pvc   Bound    pvc-98b892534d53439e   10Gi       RWO            vultr-block-storage   <unset>                 19s

Deploy the MariaDB StatefulSet

StatefulSets manage the deployment and scaling of a set of Pods. Follow the below steps to create a new ConfigMap and deploy the MariaDB StatefulSet to your cluster.

1. Create a new ConfigMap resource file mariadb-config.yaml.

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   $ nano mariadb-config.yaml

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2. Add the following contents to the file.

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   apiVersion: v1
   kind: ConfigMap
   metadata:
       name: mariadb-config
   data:
       my.cnf: |
           [mysqld]
           bind-address=0.0.0.0
           default_storage_engine=InnoDB
           innodb_file_per_table=1
           max_connections=1000

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   Save and close the file.

   The above configuration creates a new ConfigMap mariadb-config that contains the default my.cnf configuration file for a MariaDB instance including listening on all network interfaces, InnoDB, and support for up to 1000 connections.

3. Apply the ConfigMap resource to your cluster.

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   $ kubectl apply -f mariadb-config.yaml

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4. Create a new MariaDB StatefulSet YAML file.

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   $ nano mariadb-statefulset.yaml

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5. Add the following contents to the file. Replace strong_password with your desired root database user password.

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   apiVersion: apps/v1
   kind: StatefulSet
   metadata:
     name: mariadb
   spec:
     serviceName: "mariadb"
     replicas: 1
     selector:
       matchLabels:
         app: mariadb
     template:
       metadata:
         labels:
           app: mariadb  # Ensure this label matches the selector
       spec:
         containers:
           - name: mariadb
             image: mariadb:latest
             ports:
               - containerPort: 3306
                 name: mariadb
             env:
               - name: MYSQL_ROOT_PASSWORD
                 value: "strong_password"
             volumeMounts:
               - name: mariadb-storage
                 mountPath: /var/lib/mysql
               - name: config-volume
                 mountPath: /etc/mysql/conf.d
         volumes:
           - name: config-volume
             configMap:
               name: mariadb-config
     volumeClaimTemplates:
       - metadata:
           name: mariadb-storage
         spec:
           accessModes: [ "ReadWriteOnce" ]
           resources:
             requests:
               storage: 10Gi

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   Save and close the file.

   The above configuration creates a new StatefulSet mariadb that deploys a single instance of the MariaDB database. It creates a new PersistentVolumeClaim with 10 GB of storage and mounts it using the /var/lib/mysql path. The database container uses the latest MariaDB image, exposes port 3306, and sets the root database user password using an environment variable. In addition, the ConfigMap mariadb-config is mounted to apply custom configurations to the instance.

6. Apply the resource to your cluster.

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   $ kubectl apply -f mariadb-statefulset.yaml

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7. Verify that the StatefulSet is created.

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   $ kubectl get statefulset mariadb

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   Output:

   NAME      READY   AGE
   mariadb   1/1     31s

8. View the MariaDB Pods and verify that they're running.

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   $ kubectl get pods -l app=mariadb

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   Output:

   NAME        READY   STATUS    RESTARTS   AGE
   mariadb-0   1/1     Running   0          49s

Access MariaDB

Follow the steps below to create a service resource that exposes the MariaDB Pod and enable access to MariaDB.

1. Create a new Service resource file mariadb-service.yaml.

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   $ nano mariadb-service.yaml

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2. Add the following contents to the file.

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   apiVersion: v1
   kind: Service
   metadata:
       name: mariadb
   spec:
       ports:
       - port: 3306
         targetPort: 3306
       selector:
           app: mariadb

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   Save and close the file.

3. Apply the resource to your cluster.

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   $ kubectl apply -f mariadb-service.yaml

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4. Verify that the new service is created.

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   $ kubectl get svc mariadb

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   Output:

   NAME      TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)    AGE
   mariadb   ClusterIP   10.107.200.143   <none>        3306/TCP   4s

5. Access the MariaDB console using kubectl. Replace strong_password with your root database user password you set earlier.

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   $ kubectl run -it --rm --image=mysql:latest --restart=Never mysql-client -- mysql -h mariadb -u root -pstrong_password

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   The above command starts an interactive MySQL client pod using the latest MySQL image and connects to the MariaDB server using the root database user password. The connection Pod is removed when the session ends without restarting it. Your database console should look like the one below when the command is successful.

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   mysql> 

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6. View all available MariaDB databases.

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   mysql> show databases;

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   Output:

   +---------------------+
   | Database            |
   +---------------------+
   | #mysql50#lost+found |
   | information_schema  |
   | mysql               |
   | performance_schema  |
   | sys                 |
   +---------------------+
   5 rows in set (0.00 sec)

7. Exit the MySQL console.

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   mysql> exit;

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Scale the MariaDB Deployment (Up & Down)

Scaling a MariaDB deployment up or down is important when managing resource allocation based on demand. Scaling up increases capacity to handle higher loads or more connections, ensuring optimal performance during peak times. Scaling down reduces resource usage when the demand decreases to save costs and optimize infrastructure usage. Follow the below steps to scale the MariaDB deployment up and down.

1. Scale up the MariaDB deployment to 3 replicas.

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   $ kubectl scale statefulset mariadb --replicas=3

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2. Verify that the MariaDB deployment is scaled.

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   $ kubectl get statefulset mariadb

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   Output:

   NAME      READY   AGE
   mariadb   3/3     13m

3. View all Pods created by the StatefulSet.

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   $ kubectl get pods -l app=mariadb

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   Output:

   NAME        READY   STATUS    RESTARTS   AGE
   mariadb-0   1/1     Running   0          14m
   mariadb-1   1/1     Running   0          47s
   mariadb-2   1/1     Running   0          27s

4. Scale down the MariaDB deployment to 2 replicas.

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   $ kubectl scale statefulset mariadb --replicas=2

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5. Verify that the MariaDB deployment is scaled down.

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   $ kubectl get statefulset mariadb

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   Output:

   NAME      READY   AGE
   mariadb   2/2     15m

6. View the remaining Pod created by the StatefulSet.

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   $ kubectl get pods -l app=mariadb

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   Output:

   NAME        READY   STATUS    RESTARTS   AGE
   mariadb-0   1/1     Running   0          15m
   mariadb-1   1/1     Running   0          92s

Conclusion

You have deployed MariaDB on Kubernetes using a Vultr Kubernetes Engine (VKE) cluster. You set up Persistent Volumes for data storage, deployed MariaDB as a StatefulSet, accessed the database, and scaled the deployment. You can further enhance MariaDB with advanced configurations and monitoring tools to suit your production needs.