HAproxy vs Metallb

HAproxy vs Metallb? Which one is better?

As Kubernetes continues to power mission-critical workloads, load balancing remains a crucial component, especially in bare-metal environments where cloud-native solutions like AWS ELB or GCP Load Balancer aren’t available out of the box.

In these setups, DevOps teams often turn to HAProxy and MetalLB as their go-to solutions for managing ingress traffic and achieving high availability.

Both tools are popular in the Kubernetes ecosystem, but they serve different purposes and excel in different scenarios.

HAProxy, a powerful and highly configurable load balancer and proxy server, has been trusted for years in production systems.

On the other hand, MetalLB is a lightweight, Kubernetes-native load balancer designed specifically for bare-metal clusters, enabling external access via standard Layer 2 or BGP protocols.

In this blog post, we’ll explore the differences, strengths, and trade-offs between HAProxy and MetalLB.

We’ll break down key criteria such as:

Architecture and integration with Kubernetes
Ease of configuration
Protocol support and flexibility
Performance and scalability
Use case recommendations

Whether you’re building a highly available ingress solution or just trying to expose services in your on-prem cluster, this comparison will help you decide which tool fits your use case best.

Additional Resources

🔗 HAProxy Official Site
🔗 MetalLB GitHub Repository

✅ Load Balancer for Kubernetes – A full overview of Kubernetes load balancing options
✅ Optimizing Kubernetes Resource Limits – Ensure your workloads run smoothly with tuned resource configs

✅ Kubernetes Scale Deployment – Learn how to scale applications efficiently within your clusters

What is HAProxy?

HAProxy (High Availability Proxy) is a widely adopted open-source software that provides high-performance TCP (Layer 4) and HTTP (Layer 7) load balancing and proxying.

Originally released in 2001, HAProxy has become a staple in high-traffic websites and mission-critical systems due to its stability, efficiency, and advanced feature set.

Key Features

Layer 4 and Layer 7 Load Balancing: Route traffic based on IP and TCP headers (L4) or more complex rules such as HTTP headers, cookies, or request paths (L7).
Reverse Proxying: Acts as a secure entry point between clients and backend services.
TLS/SSL Termination: Handles encryption/decryption of traffic, offloading the burden from backend services.
Sticky Sessions & Load Balancing Algorithms: Supports multiple algorithms like round-robin, least connections, and source IP hash.
Health Checks: Continuously monitors the health of backend services and reroutes traffic accordingly.

HAProxy in Kubernetes

Although HAProxy is not Kubernetes-native, it integrates effectively using tools like:

HAProxy Ingress Controller – an ingress controller built on top of HAProxy, offering dynamic configuration through Kubernetes resources.
Custom ConfigMaps or CRDs – allows fine-tuning HAProxy’s behavior using native Kubernetes objects.

HAProxy excels in complex routing scenarios, especially where deep customization and fine-grained control are needed.

It’s also favored in hybrid environments where Kubernetes services need to interface with legacy systems or external networks.

Use Cases Beyond Kubernetes

Load balancing for web applications in traditional VMs or bare-metal environments.
Acting as a reverse proxy for microservices or APIs.
Providing TLS offloading and rate limiting at the edge.

Scaling monolithic applications without code changes.

What is MetalLB?

MetalLB is a load-balancer implementation designed specifically for Kubernetes clusters running on bare-metal infrastructure.

Unlike cloud providers (AWS, GCP, Azure) which offer built-in load balancers, bare-metal environments lack native support—MetalLB fills this gap by providing a Kubernetes-native solution that integrates seamlessly with standard Kubernetes networking.

Background and Purpose

MetalLB was created to solve a fundamental problem: how do you expose services externally in Kubernetes when you’re not in a cloud environment?

Kubernetes supports LoadBalancer type services, but without a cloud controller, this feature is unavailable on bare-metal.

MetalLB enables this functionality, making it a go-to choice for developers and DevOps teams running Kubernetes on-premise.

Native Kubernetes Load Balancer for Bare-Metal

MetalLB integrates with Kubernetes just like a cloud load balancer would.

When a user creates a service of type LoadBalancer, MetalLB allocates an external IP and ensures traffic to that IP is properly routed to the appropriate pods.

Key capabilities:

Works with existing Kubernetes service objects — no need for special CRDs or custom resources.
Lightweight and easy to install — typically deployed using a single manifest.
Supports both IPv4 and IPv6 addressing.

Modes of Operation: Layer 2 and BGP

MetalLB supports two main modes for advertising IP addresses:

Layer 2 Mode:
- Uses ARP (Address Resolution Protocol) to announce service IPs on the local network.
- Easiest to set up — ideal for small clusters or home labs.
- Minimal network configuration required.
BGP (Border Gateway Protocol) Mode:
- MetalLB peers with your network routers to advertise IPs.
- Better suited for production-grade environments with more complex networking.
- Offers more fine-grained control and scalability.

Each mode has its pros and cons depending on the network infrastructure and operational complexity you’re willing to manage.

HAProxy vs MetalLB: Feature Comparison

When deciding between HAProxy and MetalLB for Kubernetes load balancing on bare-metal, understanding their core differences is essential.

While both serve the goal of exposing services externally, their approaches, flexibility, and operational models differ significantly.

1. Architecture and Deployment

HAProxy:
- Acts as a standalone reverse proxy and load balancer.
- Typically deployed as a DaemonSet, sidecar, or externally to the cluster.
- Needs manual configuration or a controller (e.g., HAProxy Ingress) to work with Kubernetes.
MetalLB:
- Integrated directly into Kubernetes via a native controller model.
- Works seamlessly with Kubernetes LoadBalancer type services.
- Requires minimal configuration — just a ConfigMap to define IP ranges and mode (Layer 2/BGP).

2. Layer Support

HAProxy:
- Supports Layer 4 (TCP/UDP) and Layer 7 (HTTP/HTTPS).
- Advanced routing, SSL termination, HTTP header manipulation, and load balancing algorithms.
MetalLB:
- Primarily a Layer 2 or Layer 3 (BGP) IP address announcer.
- Does not perform application-layer routing or SSL termination itself.
- Meant to expose services, not to route or inspect traffic.

3. Use Case Fit

HAProxy:
- Ideal for complex routing rules, TLS termination, and high-performance HTTP traffic.
- Useful outside of Kubernetes too—great as an edge gateway or ingress controller.
MetalLB:
- Designed for Kubernetes-native external load balancing.
- Perfect when you need a simple, IP-based approach to expose services without cloud LBs.

4. Ease of Use and Integration

HAProxy:
- More complex to configure and manage.
- Powerful but requires manual config files or CRDs with ingress controllers.
MetalLB:
- Simple and declarative configuration using Kubernetes-native concepts.
- Works automatically with kubectl expose and Service of type LoadBalancer.

5. Flexibility & Extensibility

HAProxy:
- Extremely flexible with advanced features like:
  - Rate limiting
  - Sticky sessions
  - ACL-based routing
- Can be scripted or templated for dynamic setups.
MetalLB:
- Limited in scope by design—focuses on IP advertisement, not traffic routing.
- Not suitable for app-layer traffic manipulation or TLS handling.

6. Community and Ecosystem

HAProxy:
- Mature, widely adopted with a large community and commercial support.
- Rich ecosystem of tools and integrations.
MetalLB:
- Strong adoption among Kubernetes bare-metal users.
- Actively maintained and community-driven.
- Lightweight, with a narrower but focused scope.

In the next section, we’ll dive into real-world use cases and how to choose the right tool based on your environment.

Use Cases for HAproxy vs Metallb

When choosing between HAProxy and MetalLB for Kubernetes load balancing on bare-metal, the right option depends heavily on your infrastructure needs, traffic patterns, and operational complexity.

Below, we break down when to use each tool—and how you can even combine them for a robust solution.

✅ When to Use MetalLB

MetalLB excels in scenarios where simplicity, Kubernetes-native integration, and basic external access are top priorities:

Bare-Metal Clusters Needing External IPs

MetalLB provides a much-needed LoadBalancer service type for environments without cloud provider integrations.
It assigns external IPs to services using Layer 2 or BGP announcements—making it an ideal solution for on-prem or private datacenters.
Simple Deployments with Minimal Setup
If your services don’t require complex routing, SSL termination, or advanced traffic policies, MetalLB can get you up and running with minimal configuration.
It’s also great for dev/test clusters where ease of use is key.
Kubernetes-Native Simplicity
MetalLB works seamlessly with Kubernetes service definitions and requires little to no additional tooling to manage or maintain.

✅ When to Use HAProxy

HAProxy is the better fit when your load balancing requirements go beyond basic IP-level exposure:

Complex Routing Logic & TLS Termination
Need to direct traffic based on hostname, URL path, headers, or cookies? HAProxy’s Layer 7 features make it ideal for API gateways, multi-tenant environments, and SSL offloading.
Application-Layer Load Balancing Needs
For HTTP/HTTPS traffic, HAProxy supports advanced features like:
- Sticky sessions
- Rate limiting
- Blue-green or canary deployments
- Backend health checks
Enterprise-Grade Ingress Control
Many organizations use HAProxy as an Ingress controller in Kubernetes, especially when high-performance HTTP handling and fine-tuned configurations are critical.

🤝 Combining Both: MetalLB + HAProxy

One of the most powerful setups is using MetalLB and HAProxy together:

MetalLB assigns an external IP to a Kubernetes Service of type LoadBalancer.
That service points to an HAProxy Ingress Controller or reverse proxy running in-cluster.
HAProxy then handles the application-layer routing, TLS termination, and advanced logic.

This hybrid model gives you:

The simplicity and IP management of MetalLB
The full power and flexibility of HAProxy at the edge

Up next, we’ll explore setup and configuration differences

HAproxy vs Metallb: Setup and Configuration Differences

Understanding the setup process for both MetalLB and HAProxy is crucial for determining which tool best fits your Kubernetes environment.

While both are powerful, they differ significantly in their installation, configuration complexity, and networking model.

🔧 Installing and Configuring MetalLB

MetalLB is designed to be Kubernetes-native, lightweight, and relatively straightforward to install:

Install MetalLB via manifest or Helm
You can deploy MetalLB using a simple manifest or Helm chart. It’s usually deployed in the metallb-system namespace.
Configure a Layer 2 or BGP address pool
- Layer 2 mode requires no special routing setup—just a pool of IPs that are on the same subnet as your cluster nodes.
- BGP mode integrates with your existing router infrastructure to advertise service IPs dynamically.
Assign External IPs to LoadBalancer Services
Once MetalLB is running, any Kubernetes service of type LoadBalancer will automatically get an external IP from the pool.

📌 For clusters using MetalLB in production, also consider reading our guide on Kubernetes resource optimization to avoid overcommitting compute resources.

🚀 Deploying HAProxy as an Ingress Controller

HAProxy requires a more involved setup when used as a Kubernetes ingress controller, but offers significantly more control over HTTP(S) traffic:

Install HAProxy Ingress via Helm or YAML

Use the HAProxy Ingress Controller Helm chart or a custom YAML manifest.
You’ll typically run HAProxy in its own namespace, exposing it with a LoadBalancer or NodePort service.
Configure Ingress Resources
Define Ingress objects for each application or service you want HAProxy to expose.
These control routing rules, TLS settings, and backend service targets.
Enable TLS, Advanced Routing, and Health Checks
HAProxy supports annotations or ConfigMaps to control behaviors like:
- Path and host-based routing
- SSL/TLS certificate handling
- Rate limiting and whitelisting

📌 If you’re exploring advanced traffic strategies, check out our post on Canary Deployment vs. Blue-Green Deployment for techniques that pair well with HAProxy.

🌐 Network Architecture and IP Management

Feature	MetalLB	HAProxy Ingress Controller
IP Assignment	External IPs via L2 or BGP	Typically behind MetalLB or NodePort
L4 or L7	Layer 2 (IP only)	Layer 7 (HTTP/HTTPS)
TLS Termination	Not supported	Fully supported
Ingress Controller Role	Not applicable	Acts as a full ingress controller

MetalLB handles external connectivity at Layer 2/3, whereas HAProxy is focused on application-layer (Layer 7) traffic routing.

In many setups, MetalLB provides the external IP, and HAProxy handles the smarter traffic logic behind it.

Performance and Reliability Considerations

When evaluating HAProxy vs MetalLB for Kubernetes environments, understanding how each performs under load—and how reliably they handle traffic—is essential.

This section compares their throughput, latency, and failover capabilities.

⚡ Throughput and Latency Comparison

MetalLB is not a proxy or traffic processor—it simply assigns external IPs to services of type LoadBalancer.
Once the IP is assigned, traffic flows directly to the Kubernetes nodes. Because of this:
- Latency is minimal, limited only by the network path to the node.
- Throughput depends on the underlying Kubernetes service (often backed by iptables, IPVS, or eBPF) and node networking.
HAProxy, on the other hand, is a full reverse proxy that actively processes traffic.
- It supports Layer 7 features like request routing, TLS termination, connection reuse, and compression.
- Latency is slightly higher due to traffic inspection, but HAProxy is highly optimized and can handle tens of thousands of requests per second efficiently.
- It supports multithreading and connection pooling for improved throughput.

✅ Verdict: Use MetalLB when minimal overhead is crucial. Use HAProxy when you need intelligent traffic routing with manageable latency trade-offs.

🛡️ High Availability Configurations

Both tools support high availability (HA), but in different ways:

MetalLB (Layer 2 Mode): Only one node at a time advertises the IP. If the node fails, another takes over.
- Failover time can be tuned with arp-announce settings but is not instant.
- BGP Mode offers faster failover by leveraging dynamic routing protocols.
HAProxy: Typically deployed as a replicated deployment with multiple HAProxy pods exposed via a LoadBalancer or NodePort service.
- Works seamlessly with Kubernetes readiness probes and PodDisruptionBudgets.
- You can use MetalLB or other solutions (like Keepalived or external LBs) to assign a highly available IP.

📌Learn how to configure these setups properly in our Kubernetes Load Balancer Guide.

🌐 Failover and Traffic Handling Under Load

MetalLB is not a bottleneck—it delegates traffic flow to the Kubernetes networking layer. However, it’s not aware of pod health or request failures.
HAProxy excels in:
- Circuit breaking and rate limiting
- Health-based routing (e.g., auto-removing unhealthy pods)
- Connection retries and buffering

🧠 Pro Tip: For critical workloads, consider combining MetalLB (for external access) with HAProxy (for smart request handling) to get the best of both worlds.

Security and Observability

When deciding between HAProxy vs MetalLB in a Kubernetes environment, it’s essential to understand how each tool addresses security and observability.

While both serve distinct purposes, their capabilities in these areas can heavily influence your architecture decisions.

🔐 TLS, Authentication, and Rate Limiting in HAProxy

HAProxy shines in application-layer security features, making it a strong choice for environments that require granular traffic control and encryption.

TLS Termination: HAProxy can handle TLS encryption and decryption at the ingress level, allowing you to centralize certificate management.
Mutual TLS (mTLS): Supports advanced configurations for secure communication between clients and services.
Authentication: Basic auth, JWT token validation, and integration with external auth services are all supported.
Rate Limiting: Built-in capabilities allow you to throttle traffic per IP, path, or user session, helping protect against abuse or DDoS-style attacks.
WAF (Web Application Firewall): You can integrate HAProxy with ModSecurity or other WAFs for additional protection.

✅ Best for environments that require fine-grained access control and encrypted communication.

⚙️ MetalLB’s Simplicity and External Dependencies

MetalLB’s security model is more focused on network-level exposure than traffic control:

No built-in TLS or auth: MetalLB simply announces external IPs for LoadBalancer services. Any TLS handling must be done by an ingress controller or the application itself.
Layer 2 Mode: Vulnerable to ARP spoofing if the network is not properly segmented or secured.
BGP Mode: Relies on secure peering with routers; you should configure BGP with MD5 authentication or use a secure network.
RBAC and Namespace Scope: MetalLB can be scoped to specific namespaces for access control.

⚠️ Security depends on proper network configuration and additional tooling.

📊 Logging and Metrics Support

HAProxy:
- Exposes a detailed Prometheus metrics endpoint for insight into connections, errors, response times, and backend health.
- Full support for structured logging (via syslog or stdout).
- Compatible with observability stacks like Prometheus + Grafana, Datadog, or ELK.
MetalLB:
- Exposes Prometheus-compatible metrics such as IP assignment events, BGP session states, and service advertisements.
- Logging is lightweight but useful for diagnosing IP address assignment issues.
- Works well with tools like Prometheus for basic visibility.

📌 If you’re building observability into your clusters, check out our comparison of Datadog vs Grafana or Datadog vs Kibana for monitoring insights.

Summary

Feature	HAProxy	MetalLB
TLS Termination	✅ Yes (built-in)	❌ No (external required)
Authentication	✅ Yes (basic & advanced)	❌ No
Rate Limiting	✅ Yes	❌ No
Observability	✅ Rich metrics, logs	✅ Basic metrics
Security Scope	Application-layer	Network-layer

Up next: we’ll wrap up with final thoughts and a recommendation in the Conclusion.

Conclusion

Choosing between HAProxy and MetalLB depends heavily on your Kubernetes environment, workload requirements, and operational complexity.

While both tools can function within bare-metal Kubernetes setups, they serve distinct roles in the load balancing ecosystem.

🔑 HAproxy vs Metallb: Summary of Key Differences

Feature	HAProxy	MetalLB
Primary Function	Layer 4/7 load balancer, ingress proxy	Kubernetes-native external IP assigner
TLS Termination	✅ Built-in	❌ Not included
Traffic Routing	Advanced (host/path-based, sticky sessions)	Basic L2/BGP IP routing
Configuration Complexity	Higher – requires templating or controller	Simple – YAML-based setup
Best For	Application-layer control & security	Exposing services on bare-metal clusters
Observability & Logging	Detailed metrics and logs	Lightweight Prometheus metrics

🧭 HAproxy vs Metallb: How to Choose Based on Your Kubernetes Environment

Bare-metal cluster, simple setup?
👉 Use MetalLB to expose services via external IPs with minimal complexity.
Need TLS termination or application-layer routing?
👉 Go with HAProxy as your ingress controller for rich traffic control.
Want both benefits?
👉 Combine MetalLB (for external IP advertisement) with HAProxy Ingress Controller (for L7 routing and TLS). This hybrid approach is common in production-grade Kubernetes environments.

✅ HAproxy vs Metallb: Final Recommendations

Startups or home labs: MetalLB is lightweight, fast to deploy, and perfect for basic use cases.
Production environments: Use HAProxy where advanced routing, TLS, and observability matter.
Hybrid approach: Combine both—use MetalLB to allocate IPs and HAProxy to manage traffic securely.

🔗 Further Reading: