Kubernetes Operators for MariaDB

Operators basically instruct Kubernetes about how to manage a certain technology. Kubernetes comes with some default operators, but it is possible to create custom operators. Operators created by the community can be found on OperatorHub.io.

Custom Operators

Kubernetes provides a declarative API. To support a specific (i.e. MariaDB) technology or implement a desired behavior (i.e. provisioning a replica), we extend Kubernetes API. This involves creating two main components:

• A custom resource.
• A custom controller.

A custom resource adds an API endpoint, so the resource can be managed via the API server. It includes functionality to get information about the resource, like a list of the existing servers.

A custom controller implements the checks that must be performed against the resource to check if its state should be corrected using the API. In the case of MariaDB, some reasonable checks would be verifying that it accepts connections, replication is running, and a server is (or is not) read only.

MariaDB Operator

mariadb-operator is a Kubernetes operator that allows you to run and operate MariaDB in a cloud native way. It aims to declaratively manage MariaDB instances using Kubernetes CRDs instead of imperative commands.

It's available in both Artifact Hub and Operator Hub and supports the following features:

• Easily provision MariaDB servers in Kubernetes.
• Highly configurable MariaDB servers.
• Multiple HA modes: Galera and SemiSync Replication. SemiSync replicaton is alpha and not recommended at this time.
• Automated primary failover.
• Automated Galera cluster recovery.
• Enhanced HA with https://github.com/mariadb-operator/mariadb-operator/tree/main/docs/MAXSCALE.mdMaxScale: a sophisticated database proxy, router, and load balancer designed specifically for and by MariaDB.
• Flexible storage configuration. Volume expansion.
• Take and restore backups.
• Scheduled backups.
• Multiple backup storage types: S3 compatible, PVCs and Kubernetes volumes.
• Backup retention policy.
• Backup compression: bzip2 and gzip algorithms supported.
• Target recovery time: infer which backup to restore.
• Bootstrap new instances from: Backups, S3, PVCs ...
• Multiple update strategies: ReplicasFirstPrimaryLast, RollingUpdate, OnDelete and Never.
• Cluster-aware rolling update: roll out replica Pods one by one, wait for each of them to become ready, and then proceed with the primary Pod.
• Automated data-plane updates.
• my.cnf configuration. Automatically trigger updates when my.cnf changes.
• Suspend operator reconciliation for maintenance operations.
• Prometheus metrics via mysqld-exporter|.
• Declaratively manage SQL resources: users, grants and logical databases.
• Configure connections for your applications.
• Orchestrate and schedule sql scripts.
• Validation webhooks to provide CRD immutability.
• Additional printer columns to report the current CRD status.
• CRDs designed according to the Kubernetes API conventions.
• Install it using helm, OLM or static manifests.
• Multiple deployment modes: cluster-wide and single namespace.
• Multi-arch distroless image.
• GitOps friendly.

Please, refer to the documentation, the API reference and the example suite for further detail.

Content initially contributed by Vettabase Ltd. Updated 11/6/24 by MariaDB.