Fabio is an HTTP and TCP reverse proxy that configures itself with data from Consul.

Traditional load balancers and reverse proxies need to be configured with a config file. The configuration contains the hostnames and paths the proxy is forwarding to upstream services. This process can be automated with tools like consul-template that generate config files and trigger a reload.

Fabio works differently since it updates its routing table directly from the data stored in Consul as soon as there is a change and without restart or reloading.

When you register a service in Consul all you need to add is a tag that announces the paths the upstream service accepts, e.g. urlprefix-/user or urlprefix-/order and fabio will do the rest.

MetalLB is a load-balancer implementation for bare metal Kubernetes clusters, using standard routing protocols.

Why?

Kubernetes does not offer an implementation of network load-balancers (Services of type LoadBalancer) for bare metal clusters. The implementations of Network LB that Kubernetes does ship with are all glue code that calls out to various IaaS platforms (GCP, AWS, Azure…). If you’re not running on a supported IaaS platform (GCP, AWS, Azure…), LoadBalancers will remain in the “pending” state indefinitely when created.

Bare metal cluster operators are left with two lesser tools to bring user traffic into their clusters, “NodePort” and “externalIPs” services. Both of these options have significant downsides for production use, which makes bare metal clusters second class citizens in the Kubernetes ecosystem.

MetalLB aims to redress this imbalance by offering a Network LB implementation that integrates with standard network equipment, so that external services on bare metal clusters also “just work” as much as possible.

The Pound program is a reverse proxy, load balancer and HTTPS front-end for Web server(s). Pound was developed to enable distributing the load among several Web-servers and to allow for a convenient SSL wrapper for those Web servers that do not offer it natively. Pound is distributed under the GPL - no warranty, it's free to use, copy and give away.
WHAT POUND IS:

a reverse-proxy: it passes requests from client browsers to one or more back-end servers.
a load balancer: it will distribute the requests from the client browsers among several back-end servers, while keeping session information.
an SSL wrapper: Pound will decrypt HTTPS requests from client browsers and pass them as plain HTTP to the back-end servers.
an HTTP/HTTPS sanitizer: Pound will verify requests for correctness and accept only well-formed ones.
a fail over-server: should a back-end server fail, Pound will take note of the fact and stop passing requests to it until it recovers.
a request redirector: requests may be distributed among servers according to the requested URL.

Pound is a very small program, easily audited for security problems. It can run as setuid/setgid and/or in a chroot jail. Pound does not access the hard-disk at all (except for reading the certificate file on start, if required) and should thus pose no security threat to any machine.