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{{Navigation Wikimedia infrastructure|expand=caching}}
#REDIRECT [[Caching overview#LVS and Varnish infrastructure]]
== LVS and Varnish infrastructure ==
[[File:Wikipedia_webrequest_flow_2015-10.png|thumb|Wikipedia request flow]]
[[File:WMF Inbound Text Traffic Diagram.svg|750px|Diagram of "text" traffic flow through Wikimedia front edge LVS/nginx/Varnish infrastructure.]]
=== Notes ===
[[esams]] is representative of all cache-only sites; [[ulsfo]] is similar.
"[[|upload]]" and "mobile" traffic operate similarly to "text" shown here.
When [[LVS]] balances traffic to the :80 [[varnish]]es directly for HTTP, it choses randomly.  For :443 to the nginxes, it uses a hash of the client IP to help with SSL session persistence.
Within the caching layer (cp[1234]xxx machines), the jump from [[nginx]] to varnish:80 is direct on the local host only.
However, the jump from varnish:80 (frontend) to varnish:3128 (backend) is different: for that jump, we hash on the URL (etc) when balancing to the backends to divide the cache space among all machines, and thus the request typically moves from one machine to another within the cache layer here.

Latest revision as of 16:38, 1 July 2020