Linux Virtual Server vs MetalLB

Linux Virtual Server (LVS) turns a cluster of real Linux servers into one virtual server for users. Its IPVS component performs layer 4 balancing in the Linux kernel, directing TCP and UDP requests sent to a virtual service IP toward servers behind it. Supported forwarding methods are NAT, FULLNAT, tunneling, and direct routing. The project lists web, cache, mail, FTP, media, and VoIP services as applications. Capacity can be changed by adding or removing cluster nodes. Failure detection can identify node or daemon problems and reconfigure the system for availability. Keepalived checks server-pool state at layers 3, 4, and 5 and tells the kernel to remove a failed server. KTCPVS supplies application-level balancing but is under development. LVS is free GPL-licensed software for Linux and self-hosted use. Administration uses ipvsadm, with documentation for configurations, scheduling, high availability, and DoS defense.

MetalLB provides network load balancing for Kubernetes clusters that do not run on a cloud provider. It assigns service IP addresses from operator-configured pools and announces them through ARP, NDP, or BGP, depending on the chosen mode. In layer 2 mode, one cluster machine announces an address using ARP for IPv4 or NDP for IPv6. In BGP mode, cluster machines peer with nearby routers, which can distribute traffic across multiple nodes. The recommended FRR-K8s mode supports BFD, IPv6, and merging additional FRR configuration. MetalLB is open source, with no paid plans listed. Installation options include Kubernetes manifests, Kustomize, Helm, and an Operator on OperatorHub. After installation it remains idle until configured with resources such as an IPAddressPool in its deployment namespace. Requirements include Kubernetes 1.13.0 or later, a compatible cluster network, and IPv4 addresses. The project lists AWS, Azure, DigitalOcean, and Google Cloud as unsupported and says it is generally incompatible with cloud providers. MetalLB describes itself as a beta project and cautions that its configuration format may change incompatibly as development continues.