HAProxy is free, open source software that provides a high availability load balancer and proxy server for TCP and HTTP-based applications that spreads requests across multiple servers. It is written in C and has a reputation for being fast and efficient (in terms of processor and memory usage).
Use HAProxy as a reverse proxy⚑
reverse proxy is a type of proxy server that retrieves resources on behalf of a client from one or more servers. These resources are then returned to the client, appearing as if they originated from the server itself. Unlike a forward proxy, which is an intermediary for its associated clients to contact any server, a reverse proxy is an intermediary for its associated servers to be contacted by any client. In other words, a proxy is associated with the client(s), while a reverse proxy is associated with the server(s); a reverse proxy is usually an internal-facing proxy used as a 'front-end' to control and protect access to a server on a private network.
It can be done at Web server level (Nginx, Apache, ...) or at load balancer level.
This HAProxy post shows how to translate Apache's proxy pass directives to the HAProxy configuration.
frontend ft_global acl host_dom.com req.hdr(Host) dom.com acl path_mirror_foo path -m beg /mirror/foo/ use_backend bk_myapp if host_dom.com path_mirror_foo backend bk_myapp [...] # external URL => internal URL # http://dom.com/mirror/foo/bar => http://bk.dom.com/bar # ProxyPass /mirror/foo/ http://bk.dom.com/bar http-request set-header Host bk.dom.com reqirep ^([^ :]*)\ /mirror/foo/(.*) \1\ /\2 # ProxyPassReverse /mirror/foo/ http://bk.dom.com/bar # Note: we turn the urls into absolute in the mean time acl hdr_location res.hdr(Location) -m found rspirep ^Location:\ (https?://bk.dom.com(:[0-9]+)?)?(/.*) Location:\ /mirror/foo3 if hdr_location # ProxyPassReverseCookieDomain bk.dom.com dom.com acl hdr_set_cookie_dom res.hdr(Set-cookie) -m sub Domain= bk.dom.com rspirep ^(Set-Cookie:.*)\ Domain=bk.dom.com(.*) \1\ Domain=dom.com\2 if hdr_set_cookie_dom # ProxyPassReverseCookieDomain / /mirror/foo/ acl hdr_set_cookie_path res.hdr(Set-cookie) -m sub Path= rspirep ^(Set-Cookie:.*)\ Path=(.*) \1\ Path=/mirror/foo2 if hdr_set_cookie_path
Other useful examples can be retrieved from drmalex07 or ferdinandosimonetti gists.