The Arrakis team did it with Haproxy, Reddis, and Memcached, but in a research operating system:<p><a href="http:&#x2F;&#x2F;people.inf.ethz.ch&#x2F;troscoe&#x2F;pubs&#x2F;peter-arrakis-osdi14.pdf" rel="nofollow">http:&#x2F;&#x2F;people.inf.ethz.ch&#x2F;troscoe&#x2F;pubs&#x2F;peter-arrakis-osdi14....</a><p>BSD has had userland networking for a while:<p><a href="http:&#x2F;&#x2F;www.bsdcan.org&#x2F;2014&#x2F;schedule&#x2F;events&#x2F;447.en.html" rel="nofollow">http:&#x2F;&#x2F;www.bsdcan.org&#x2F;2014&#x2F;schedule&#x2F;events&#x2F;447.en.html</a><p>I&#x27;m not sure if there&#x27;s anything comparable for Linux.