MariaDB server operator for Kubernetes

Features

• Setup a MariaDB server. Database server version can be configured in the CR file.
• Creates a new custom Database along with a user credential set for the custom database.
• Operator uses Persistent Volume where MariaDB can write its data files.
• Seamless upgrades of MariaDB is possible without loosing data.
• Take database backup at defined intervals
• Provides mariadb metrics with prometheus/mysqld_exporter

CRs

MariaDB

apiVersion: mariadb.persistentsys/v1alpha1
kind: MariaDB
metadata:
  name: mariadb
spec:
  # Keep this parameter value unchanged.
  size: 1
  
  # Root user password
  rootpwd: password

  # New Database name
  database: test-db
  # Database additional user details (base64 encoded)
  username: db-user 
  password: db-user 

  # Image name with version
  image: "mariadb/server:10.3"

  # Database storage Path
  dataStoragePath: "/mnt/data" 

  # Database storage Size (Ex. 1Gi, 100Mi)
  dataStorageSize: "1Gi"

  # Port number exposed for Database service
  port: 30685

This CR with create a database called test-db, along with user credentials. The Server image name is mentioned in "image" parameter. Database files will be stored at location: '/mnt/data'. This location should be created before applying the CR.

MariaDB Backup CR

apiVersion: mariadb.persistentsys/v1alpha1
kind: Backup
metadata:
  name: mariadb-backup
spec:
  # Backup Path
  backupPath: "/mnt/backup"

  # Backup Size (Ex. 1Gi, 100Mi)
  backupSize: "1Gi" 

  # Schedule period for the CronJob.
  # This spec allow you setup the backup frequency
  # Default: "0 0 * * *" # daily at 00:00
  schedule: "0 0 * * *"

This CR will schedule backup of MariaDB at defined schedule. The Database backup files will be stored at location: '/mnt/backup'. This location should be created before applying the CR.

MariaDB Monitor CR

apiVersion: mariadb.persistentsys/v1alpha1
kind: Monitor
metadata:
  name: mariadb-monitor
spec:
  # Add fields here
  size: 1
  # Database source to connect with for colleting metrics
  # Format: "<db-user>:<db-password>@(<dbhost>:<dbport>)/<dbname>">
  # Make approprite changes 
  dataSourceName: "root:password@(192.168.99.127:30685)/test-db"
  # Image name with version
  # Refer https://registry.hub.docker.com/r/prom/mysqld-exporter for more details
  image: "prom/mysqld-exporter"

This CR will start prometheus/mysqld_exporter pod and service. Note: The database host and port should be correct for metrics to work.

Setup Instructions

MariaDB Database uses external location on host to store all DB files. This location is default set to "/mnt/data" in CR file. Similarly Database backup files are stored at default location "/mnt/backup" and can be configured in Backup CR file. Ensure that these paths exist and have all necessary permissions.

Check if there are no existing Persistent Volumes defined for same locations. If so, delete those PVs before applying CRs

Start operator and create all resources

Run the following make command to start all resources:

# make install

By default, all resources will be created in a namespace called "mariadb"

Verify MariaDB Deployment

Verify list of pods. One Operator and One Server pod should be created.

# kubectl get pods -n mariadb
NAME                              READY   STATUS    RESTARTS   AGE
mariadb-operator-78c95468-m824g   1/1     Running   0          118s
mariadb-server-778b9b7cb5-nt6n5   1/1     Running   0          109s

Verify that "mariadb-service" is created.

# kubectl get svc -n mariadb
NAME                       TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)             AGE
mariadb-backup-service     ClusterIP   10.96.69.127    <none>        3306/TCP            103s
mariadb-operator-metrics   ClusterIP   10.110.31.195   <none>        8383/TCP,8686/TCP   105s
mariadb-service            NodePort    10.102.17.13    <none>        80:30685/TCP        104s

Service "mariadb-service" is a NodePort Service that exposes mariadb service on port 3306

# kubectl describe service/mariadb-service -n mariadb
Name:                     mariadb-service
Namespace:                mariadb
Labels:                   MariaDB_cr=mariadb
                          app=MariaDB
                          tier=mariadb
Annotations:              <none>
Selector:                 MariaDB_cr=mariadb,app=MariaDB,tier=mariadb
Type:                     NodePort
IP:                       10.100.40.161
Port:                     <unset>  80/TCP
TargetPort:               3306/TCP
NodePort:                 <unset>  30685/TCP
Endpoints:                172.17.0.5:3306
Session Affinity:         None
External Traffic Policy:  Cluster
Events:                   <none>

Test connectivity to MariaDB Server:

# mysql -h 192.168.29.217 -P 30685 -u db-user -pdb-user

where 192.168.29.217 is the minikube IP and 30685 is the configured NodePort. If everything is correct, mysql prompt will be presented to the user.

Test Backup Service: Ensure that cronjob is configured correctly

# kubectl get cronjob -n mariadb
NAME             SCHEDULE    SUSPEND   ACTIVE   LAST SCHEDULE   AGE
mariadb-backup   0 0 * * *   False     0        <none>          17m

At scheduled interval, a new Job will start to take database backup and create a backup file at defined location (default: /mnt/backup)

Create monitoring resources (Optional)

To enable monitoring services, you need to have external prometheus and grafana servers deployed.

Deploy prometheus operator

Install prometheus operator from operatorhub or any other mechanism.

OperatorHub link: https://operatorhub.io/operator/prometheus

Note: If you are installing from operatorhub, then by default it installs the operator in operators namespace.

Below steps assumes that its deployed in operators namespace. However you may do the changes.

Deploy prometheus and servicemonitor kinds

Install prometheus server and servicemonitor. Sample files are checked in to below location.

examples/monitoring/Prometheus.yaml

examples/monitoring/ServiceMonitor.yaml

Verify prometheus monitoring deployment

You can do forwarding to open prometheus UI locally.

#kubectl --namespace operators port-forward svc/prometheus-operated 9090

Verify metrics are present at http://localhost:9090

Deploy grafana operator

Install grafana operator from operatorhub or any other mechanism.

OperatorHub link: https://operatorhub.io/operator/grafana-operator

Note: If you are installing from operatorhub, then by default it installs the operator in my-grafana-operator namespace.

Below steps assumes that its deployed in my-grafana-operator namespace. However you may do the changes.

Deploy grafana, datasource and dashboard

Install grafana server. You can use below sample CRD

examples/monitoring/grafana-server.yaml

Install grafana datasource. You can use below sample datasource

examples/monitoring/prometheus-datasources.yaml

Verify grafana monitoring deployment

You can do forwarding to open grafana UI locally.

#kubectl --namespace my-grafana-operator port-forward svc/grafana-service 3000

Verify datasource is created at http://localhost:3000

Import grafana dashboard via UI. You can use below sample dashboard

examples/monitoring/MariaDBDashboard.json

Upgrade MariaDB server version

Mariadb server image is mentioned in CR key "image". To upgrade the Server version, change value of "image" key and reapply the CR YAML file.

# kubectl apply -f deploy/crds/mariadb.persistentsys_v1alpha1_mariadb_cr.yaml

Stop Operator and delete all resources

Run the command to delete all resources:

# make uninstall