This topic is specifically about the following two settings found in the mod_jk workers.properties files:
The official docu is at:
I found the explanation a little unclear and found a more succinct version here:
local_worker=1 indicates that it"s running on the same box as apache.
local_worker=0 indicates it"s running elsewhere.
local_worker_only=1 says only send new requests (e.g. no jsessionid
cookie/url) to workers with local_worker=1.
local_worker_only=0 says new requests to any server.
How it helps is that when you need to do maintenance on ww2, set
local_worker_only=1 on ww1 and do a graceful restart on apache. New
requests to ww1 will all go to the ww1 Tomcat instance. If a requests
comes to apache on ww1 with a ww2 jsessionid, it will still route the
request to the correct Tomcat instance. Eventually the sessions on ww2
all die off and you can cleanly bring down the instance without killing
off your users. You obviously need some other mechanism to stop HTTP
requests from being directed to apache on ww2.