Kubernetes on bare metal: 7 reasons to use Longhorn for persistent storage

Many organizations that use Kubernetes may have to choose between costly, vendor-locked proprietary arrays or cloud-native services that trade away control for ease of use. These trade-offs become even more painful when Kubernetes runs directly on bare metal.

Longhorn changes this equation entirely. Rather than requiring specialized storage infrastructure, it transforms your existing server hardware into a distributed storage system designed specifically for Kubernetes workloads. 

Whether you're managing your own data center infrastructure or leveraging platforms like Latitude.sh for rapid bare metal deployment, Longhorn provides the storage layer that makes bare metal Kubernetes truly production-ready.

1. Eliminates Vendor Lock-In and Reduces Costs

Longhorn operates as a pod within your Kubernetes clusters, requiring no specialized hardware. This design philosophy creates immediate economic benefits by transforming commodity hardware into distributed block storage.

This flexibility proves especially valuable when using modern bare metal platforms like Latitude.sh, where you can deploy servers globally in seconds and immediately begin building distributed storage clusters without vendor-specific hardware requirements.

Key advantages:

• Works consistently across on-premises, hyperscalers, and other environments

• No vendor dependencies that tether you to particular platforms

• Hardware flexibility becomes a strategic advantage rather than a constraint

2. Delivers Performance That Matches Bare Metal Capabilities

Longhorn's microservices-based architecture stands apart from traditional storage systems that rely on centralized controllers. 

Each volume has its own dedicated storage controller, the Longhorn engine, which essentially functions as a microservice. This distributed approach eliminates the performance bottlenecks that characterize monolithic storage solutions.

Performance benefits:

• No single controller failure brings down your entire storage system

• True horizontal scaling as you add more nodes

• Data locality features keep workloads and data on the same node, reducing network traffic

3. Provides Enterprise-Grade High Availability

Longhorn creates multiple identical copies of each volume, distributing them across different physical servers in your cluster. 

The default configuration maintains three replicas per volume, protecting against server failures, disk crashes, or network issues that may affect individual nodes.

Resilience features:

• Automatic failover without administrative intervention

• Self-healing capabilities that rebuild replicas on healthy servers

• Anti-affinity enforcement prevents multiple replicas on identical hardware

4. Integrates Seamlessly with Kubernetes

As a Container Storage Interface (CSI) plugin, Longhorn provides seamless integration with Kubernetes' persistent volume framework. 

You can provision storage using familiar Kubernetes primitives (StorageClasses, PersistentVolumeClaims, and PersistentVolumes) without learning proprietary management interfaces.

Integration benefits:

• Automatic volume snapshots for efficient rebuilding

• ReadWriteMany (RWX) support for collaborative workloads

• Cross-cluster disaster recovery with defined recovery objectives

5. Enables Strategic ReadWriteMany (RWX) Volume Deployment

Longhorn implements RWX volumes through a share manager that creates NFS shares within the cluster, eliminating the need for external NFS servers. This capability proves essential for specific use cases while maintaining performance for other workloads.

Ideal RWX scenarios:

• Content management systems where multiple pods need access to uploaded media

• Development environments with shared codebases and build artifacts

• CI/CD pipelines passing artifacts between different nodes

6. Delivers Comprehensive Disaster Recovery

Longhorn eliminates traditional backup challenges through integrated snapshot and backup capabilities designed specifically for Kubernetes workloads. The system handles the entire process through familiar Kubernetes interfaces, eliminating the need for a separate backup infrastructure.

Disaster recovery capabilities:

• Volume snapshots capture point-in-time data states without disrupting applications

• Incremental backup transfers only changed data blocks

• Cross-cluster recovery maintains synchronized copies in remote clusters

• Support for multiple backup destinations, including NFS and S3-compatible storage

7. Optimizes Storage Locality for Maximum Performance

Longhorn provides three data locality modes that determine how replicas are distributed relative to your workloads: disabled, best-effort, and strict-local. This flexibility enables you to balance performance against availability according to specific application requirements.

For latency-sensitive workloads, such as databases and real-time analytics, data locality ensures that applications gain direct access to the server's storage subsystem, thereby bypassing network overhead entirely. 

This optimization becomes particularly powerful on platforms like Latitude.sh, where global server deployment enables you to place both compute and storage resources closer to your users while maintaining centralized management.

Performance optimization:

• Strict-local mode: Exactly one replica on the workload's node for maximum performance

• Best-effort mode: Attempts local placement while maintaining flexibility

• Disabled mode: Prioritizes availability over performance

Getting Started with Bare Metal Kubernetes

Platform Selection: Modern bare metal platforms like Latitude.sh simplify the initial deployment challenge by providing automated server provisioning and management APIs. You can deploy Kubernetes nodes globally in seconds, then layer Longhorn on top for distributed storage.

MetalLB Integration: Combine Longhorn with MetalLB to solve external access patterns. While Longhorn handles persistent storage, MetalLB provides cloud-style LoadBalancer services for physical infrastructure.

Making the Right Storage Decision

Longhorn on bare metal Kubernetes represents a practical solution that addresses real operational needs. 

Your storage architecture decisions should align with actual workload requirements. High availability through replica distribution makes sense for mission-critical applications, while smaller workloads may not justify the overhead.

The economic advantages become clear over time. Organizations with predictable workloads often find that the initial investment in properly configured bare metal infrastructure delivers better long-term value than public cloud alternatives, while Longhorn eliminates the need for expensive proprietary storage arrays.

FAQs

Q1. How does Longhorn enhance storage capabilities on bare metal Kubernetes?

Longhorn transforms standard servers into a distributed storage system for Kubernetes, providing features like high availability, disaster recovery, and efficient resource utilization without requiring specialized hardware. It offers data redundancy, performance optimization, and seamless integration with Kubernetes primitives.

Q2. What are the benefits of using ReadWriteMany (RWX) volumes with Longhorn?

RWX volumes allow multiple pods across different nodes to simultaneously read from and write to the same volume. This is crucial for applications like content management systems, collaborative workspaces, and CI/CD pipelines that require shared access to data. Longhorn implements RWX through an NFS share manager, simplifying deployment on bare metal infrastructure.

Q3. How does Longhorn's data locality feature improve performance?

Longhorn's data locality feature attempts to keep data physically close to the computation that needs it. By maintaining volume replicas on the same node as the workload, it reduces network latency and improves I/O performance, which is especially beneficial for databases, caching systems, and data analytics tools running on bare metal Kubernetes.

Q4. What disaster recovery capabilities does Longhorn offer?

Longhorn provides robust disaster recovery through features like volume snapshots, incremental backups, and cross-cluster recovery. It supports configurable recovery time objectives (RTO) and recovery point objectives (RPO), allowing organizations to implement enterprise-grade disaster recovery even with constrained resources between physical data centers.

Q5. How can administrators monitor Longhorn storage health in a Kubernetes environment?

Longhorn exposes metrics in Prometheus format, enabling easy integration with existing monitoring infrastructure. Key metrics include volume health, capacity utilization, replica distribution, and node-level resource usage. Administrators can create Grafana dashboards for visualization and set up Prometheus alert rules for proactive issue detection and response.