i was looking for lighttpd's proxy loadbalancing capabilities. Sadly i found a entry in the documentation that sticky-session - support is not implemented yet.
I also found two feature requests for sticky-session support (http://redmine.lighttpd.net/issues/959 & 804).
Is this feature on any internal roadmap or is it completely out of focus at the moment?
lighttpd has supported sticky load balancing by client IP address since lighttpd 1.4.44.
See mod_fastcgi docs for that and other options.
load-balancing algorithm for backends ("fair", "least-connection", "round-robin", "hash", or "sticky")