Storage Best Practices

Storage Best Practices in AKS

This section covers best practices for managing storage in AKS across several critical dimensions: backup and recovery, performance optimization, security, and cost management.

Backup and Recovery

Protecting your stateful workloads is crucial for business continuity. A comprehensive backup strategy should include both volume-level and application-level protection mechanisms.

Volume Snapshots

AKS supports CSI volume snapshots for point-in-time backups, providing an efficient way to capture data at specific moments. These snapshots can be used to create new volumes or restore existing ones. For critical production data, implementing regular snapshot schedules is essential to minimize potential data loss in recovery scenarios.

Cluster-Wide Backup Solutions

For comprehensive protection, consider implementing a complete backup solution:

Disaster Recovery Considerations

Effective disaster recovery goes beyond just taking backups. Create a cross-region recovery strategy for mission-critical applications by documenting your recovery processes and clearly defining Recovery Point Objectives (RPO) and Recovery Time Objectives (RTO). Regular testing of restore procedures is essential to validate your backup strategy and ensure team readiness for recovery situations.

Performance Optimization

Optimizing storage performance is essential for application responsiveness and user experience. The right storage configuration can dramatically improve your application’s performance, while poor choices can lead to bottlenecks.

Storage Class Selection

The choice of storage class has significant implications for application performance:

Volume Sizing and IOPS

When provisioning storage in AKS, consider both capacity and performance requirements. Azure disks provide more IOPS and throughput as they increase in size, so a larger disk might be necessary even if you don’t need the extra capacity. Implement monitoring of I/O metrics to identify potential performance bottlenecks before they impact application performance.

Topology Awareness

Storage performance can be significantly affected by topology considerations. Utilize the WaitForFirstConsumer volume binding mode to ensure volumes are created in the same availability zone as the pods that will use them. This approach avoids cross-zone data transfers, which can impact both performance and costs. For workloads requiring high availability, consider implementing zone-redundant storage options that replicate data across multiple availability zones.

Security

Protecting your persistent data requires a comprehensive security approach that addresses multiple layers of the storage stack.

Encryption

Data security begins with encryption. Azure disks and files are encrypted at rest by default, providing a baseline level of protection. For workloads with higher security requirements, consider using customer-managed keys to gain greater control over your encryption strategy. Additionally, for particularly sensitive data, implementing application-level encryption adds an extra layer of protection independent of the infrastructure.

Access Control

Proper access control is essential for securing your storage resources. Kubernetes RBAC (Role-Based Access Control) allows you to define precisely who can create, modify, and use storage resources within your cluster. Complement this with namespace resource quotas to prevent any single team or application from consuming excessive storage resources, which could lead to resource contention or elevated costs.

The deprecated Pod Security Policies (PSP) are being replaced by Pod Security Standards (PSS) and Pod Security Admission (PSA). Use these features to control which volumes can be mounted by pods and what permissions they have, reducing the risk of unauthorized data access.

Secrets Management

Never store credentials in PV/PVCs or StorageClass definitions, as these can be viewed by users with access to the cluster. Instead, utilize secure options like Kubernetes Secrets or, preferably, Azure Key Vault for storing sensitive storage configuration. For any credentials that must be rotated, implement automated secret rotation procedures to ensure credentials are regularly updated without disrupting applications.

Cost Management

Optimizing storage costs requires a balanced approach that meets application requirements while avoiding unnecessary expenditure. Thoughtful planning and ongoing management can significantly reduce your cloud storage costs.

Right-sizing and Efficiency

Appropriate resource allocation is the foundation of cost control. Begin by allocating only the storage capacity that’s actually needed rather than over-provisioning “just in case.” As needs grow, utilize volume expansion capabilities to increase capacity without service disruption. Regular analysis of usage patterns can identify opportunities for optimization, such as consolidating underutilized volumes or adjusting storage class selections.

Storage Class Economics

Implement storage quotas at the namespace level to prevent unexpected cost increases and to enforce equitable resource distribution across teams. Regularly scheduled reviews of unused PVCs can identify opportunities to reclaim resources that are no longer needed.

Lifecycle Management

Effective storage lifecycle management involves creating clear policies for the entire storage lifecycle:

1. Creation: Define standard volume sizes and storage classes based on workload needs
2. Usage: Monitor utilization to identify underused resources
3. Reclamation: Implement proper reclaim policies (Delete vs. Retain) based on data importance
4. Decommissioning: Establish processes to archive or delete data when no longer needed

For non-critical workloads, consider using Spot VMs with ephemeral storage to significantly reduce costs, with the understanding that such resources may be reclaimed with limited notice.

Storage Monitoring

Effective monitoring is essential for managing storage resources and ensuring optimal performance, reliability, and cost efficiency. A robust monitoring strategy helps identify issues before they impact applications and provides insights for long-term planning.

Key Metrics and Dimensions

The most effective monitoring combines real-time alerting with trend analysis to support both operational needs and capacity planning.

Monitoring Tools and Integration

Both Azure-native and open-source monitoring tools can be combined for comprehensive storage oversight:

For the most robust monitoring setup, consider using Prometheus with the kubernetes-storage-monitor exporter to collect granular metrics about PVs, PVCs, and StorageClasses. These metrics can be visualized in Grafana dashboards and integrated with Azure Monitor using the Prometheus integration to provide a unified monitoring experience.

Many teams implement a hybrid approach: using Azure Monitor for high-level oversight and integration with Azure tools, while deploying Prometheus for detailed operational metrics and alerts.

Alerting Strategy

A well-designed alerting system balances the need for timely notification against alert fatigue. Consider implementing:

1. Predictive alerts that warn of approaching capacity limits before they become critical
2. Anomaly detection to identify unusual I/O patterns that might indicate security issues or application problems
3. Backup completion alerts to ensure your data protection strategy is functioning as expected

Integrate storage alerts with your team’s communication tools (Teams, Slack) and incident management systems for prompt response to critical issues.