In the v5 Load Balancer Administration
Guide, in the chapter on Manager, Advisors, and Metric Server
functions, the advisorrequest and advisorresponse parameters for the
dscontrol server command have references only to the HTTP advisor.
However, these parameters are valid for both HTTP and HTTPS advisors.
By default, the HTTPS advisor looks for the string 200 OK in
response to its HTTP request. In some situations, the server HTTP response
does not contain the string 200 OK, in which case the HTTPS advisor marks
the server down.
Example: Caching Proxy v5.1 responds to the HTTPS advisor's HTTP request
with the following string:
Received >>>HTTP/1.1 200 Document
follows<<<
Received >>>Last-Modified: Wed, 17 Sep 2003 23:15:43
GMT<<<
Received >>>Content-Length: 2702<<<
Received >>>Content-Type: text/html<<<
Received >>>Content-Location: Frntpage.html<<<
Received >>>Accept-Ranges: bytes<<<
Received>>>Connection: Keep-Alive<<<
Received >>>Date: Wed, 01 Oct 2003 16:27:45 GMT<<<
Received >>>Server: IBM-PROXY-WTE/5.1<<<
Since the response from Caching Proxy does not contain the
default-expected advisor response of 200 OK, the HTTPS advisor marks the
server down, even though it is really up.
Using the above server HTTP response as an example, use the following
command to define the expected HTTP response for the HTTPS advisor:
server set [cluster1+ c2+...]:[port1+
p2 +...]:[ server1+ s2 +...] advisorresponse
"HTTP/1.1 200 Document"
Now when the HTTP server responds to the HTTPS advisor's HTTP request,
the advisor will find the expected string and mark the server up. |