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SPECIFICTION
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OpenELB

openelb.io

LinuxSelf-hosted
Visit openelb.io
Spec score 6.9 #16 of 32 in Load Balancing Software

What it is

OpenELB exposes Kubernetes LoadBalancer services externally in bare-metal, edge, and virtualization environments. It assigns service addresses from Eip-managed IP pools and supports BGP, Layer 2, and VIP load-balancing modes. BGP mode uses GoBGP to publish routes to peer routers and supports ECMP, while BgpConf and BgpPeer custom resources configure BGP properties. Layer 2 mode requires infrastructure that permits anonymous ARP/NDP packets. VIP mode uses VRRP for high availability. OpenELB can be installed with kubectl manifests or Helm 3 in Kubernetes 1.15 or later, and guides are listed for Kubernetes, K3s, and KubeSphere. The project currently supports IPv4 only and is not a managed service. Layer 2 and VIP modes forward through one active node, so failover can briefly interrupt services and bandwidth is limited by that node. BGP requires a router supporting BGP and ECMP. OpenELB uses Apache License 2.0.

Spec sheet

Purpose
OpenELB exposes Kubernetes LoadBalancer services to external access in bare-metal, edge, and virtualization environments.Read 4 Oct 2026 · openelb.io
Integrations
The project lists installation guides for Kubernetes, K3s and KubeSphere.Read 4 Oct 2026 · github.com
Support
The project directs users to the KubeSphere Slack channel for support and discussion.Read 4 Oct 2026 · openelb.io
License
OpenELB is licensed under the Apache License, Version 2.0.Read 4 Oct 2026 · openelb.io
Address family limit
The documentation says OpenELB currently supports only IPv4.Read 4 Oct 2026 · openelb.io
BGP configuration
Users can configure BGP properties through BgpConf and BgpPeer custom resource definitions.Read 4 Oct 2026 · openelb.io
BGP prerequisites
BGP mode requires a router that supports BGP and ECMP; the documentation recommends it for high availability without failover interruptions or bandwidth bottlenecks.Read 4 Oct 2026 · openelb.io
Installation
OpenELB can be installed in a Kubernetes cluster using kubectl manifests or Helm 3.Read 4 Oct 2026 · openelb.io
IP address pools
Eip objects provide address pools from which OpenELB assigns IP addresses to Kubernetes LoadBalancer services.Read 4 Oct 2026 · openelb.io
IP management
It provides IP address pool management for service load-balancer IPs.Read 4 Oct 2026 · openelb.io
Kubernetes requirement
Installation requires Kubernetes 1.15 or later because OpenELB requires CustomResourceDefinition v1.Read 4 Oct 2026 · openelb.io
Layer 2 constraints
Layer 2 mode requires the infrastructure to allow anonymous ARP/NDP packets, and its traffic forwarding uses one node at a time, which can cause brief interruptions during failover and a single-node bandwidth bottleneck.Read 4 Oct 2026 · openelb.io
Layer 2 limitations
Layer 2 mode forwards traffic through one active node, so failover briefly interrupts services and bandwidth is limited to that node.Read 4 Oct 2026 · openelb.io
Layer 2 prerequisites
Layer 2 mode requires the infrastructure to allow anonymous ARP/NDP packets.Read 4 Oct 2026 · openelb.io
Load-balancing modes
It supports BGP mode and Layer 2 mode.Read 4 Oct 2026 · openelb.io
Project origin
OpenELB is a KubeSphere sub-project; its repository says it was originally created by KubeSphere and is now vendor neutral and a CNCF Sandbox Project.Read 4 Oct 2026 · github.com
Project status
The repository says OpenELB was originally created by KubeSphere and is a vendor-neutral CNCF Sandbox Project.Read 4 Oct 2026 · github.com
Router requirements
BGP mode requires a router that supports BGP and ECMP; the documentation suggests Layer 2 or VIP mode when those are unavailable.Read 4 Oct 2026 · openelb.io
Routing
OpenELB supports ECMP routing and load balancing.Read 4 Oct 2026 · openelb.io
VIP constraints
VIP mode uses VRRP for high availability and is limited to 255 VRRP instances per network; failover can briefly interrupt services and traffic is limited by one node's bandwidth.Read 4 Oct 2026 · openelb.io

Strong points and limits

Strong points

  • Supports BGP, Layer 2, and VIP modes
  • Manages service IP pools with Eip objects
  • Installs through kubectl manifests or Helm 3
  • Provides ECMP routing in BGP mode
  • Licensed under Apache License 2.0

Limits

  • Supports IPv4 only
  • BGP requires a router supporting BGP and ECMP
  • Layer 2 failover briefly interrupts services
  • VIP mode allows 255 VRRP instances per network

Who it suits

It suits teams exposing Kubernetes services from self-hosted Linux environments, including bare-metal, edge, and virtualization deployments. Choice of mode depends on available router, ARP/NDP, and VRRP capabilities.

Verdict

OpenELB provides several ways to expose Kubernetes LoadBalancer services on self-hosted infrastructure. Its mode-specific network requirements and single-node limits in Layer 2 or VIP deployments should guide configuration choices.

Where Specifiction places it

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