User guide

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Also, the MIME header of the custom health check request will include the “Host:” and
“User-Agent:.” The “Host:” MIME header will be the label you used for the farm (not the
label you use for the server). The “User-Agent:” MIME header will show “WebMux health
check for <farm IP>:<port>.”
Note The HTTP server will also have its own environment variables that you can utilize
for your custom health check script. Please refer to your HTTP server manual and the
manual for your scripting language for more information about environment variables.
If you select “Custom Defined + Generic TCP” service for a farm, the health checking
process is a bit different. The health check script will pass for the following responses:
OK server/service is alive, no weight change
OVERLOAD set weight to 0, to quiesce (same as “WEIGHT=0”)
QUIESCE set weight to 0, to quiesce (same as “WEIGHT=0”)
WEIGHT=n set weight to integer n
WEIGHT-=n subtract integer n from the weight
WEIGHT+=n add integer n to the weight
However, if the custom health check script returns an unknown response or if it is missing
altogether, the WebMux will fall back to Generic TCP port checking. If the port for the
custom check is different from the server port in the farm configuration, the WebMux will do
Generic TCP port check on the server port. As long as the port is open and responding to
TCP connect, the server will be considered alive.
The conditions where the WebMux is consider the server dead will be if the custom health
check script explicitly returns “NOT OK”, or if the service port goes completely offline.