Hi Yves,
On Thu, Sep 17, 2015 at 02:12:23PM +0200, Yves Van Wert wrote:
> Hi Willy,
>
> thank you for your quick response.
>
> I've changed the parameter but this didn't make any difference. I still
> see a few connections changing backend servers without me being able to
> explain this. Do you have any other pointers as to where i can look ?
>
> New config :
> backend weblogic-forms
> mode http
> balance roundrobin
> cookie SERVERID insert indirect nocache
> option http-server-close
> option forwardfor
> option httpchk HEAD /check.txt HTTP/1.0
> option log-health-checks
> stats enable
> stats auth admin:axihaproxy
> server ias03 10.64.0.81:8888 cookie ias03 check inter 3000 rise 5
> fall 6 weight 40
> server ias04 10.64.0.82:8888 cookie ias04 check inter 3000 rise 5
> fall 6 weight 10
> server ias05 10.64.0.181:8888 cookie ias05 check inter 3000 rise 5
> fall 6 weight 40
> server ias06 10.64.0.182:8888 cookie ias06 check inter 3000 rise 5
> fall 6 weight 10
At this point your logs will be needed. Here are the possibilities :
- the client forgets to send the cookie and is redistributed
- a server occasionally fails to accept the connection and after a few
retries, the connection is sent to another one (when "option redispatch"
is present)
- a server occasionally does a down/up cycle and its requests are
redistributed but I think you said this didn't happen.
The logs will indicate what's happening when you see the request being
sent to the wrong server : the cookie flags will tell you whether an
invalid, absent, valid cookie was present and if it targetted a down or
an up server.
Just out of curiosity, would you happen to have another backend behind the
same frontend, on the same domain name, with the same cookie names ? It
would be possible that some users switch from the two sites and retrieve
another backend's cookie. For example, let's say you have 4 servers in this
farm named ia03 to ia06, and another farm has only 3 servers named ia03 to
ia05. Visitors of your first farm getting cookie ia06 will then go to the
second farm with this cookie which will be invalid, be assigned a new one
and when they come back to the first farm, they'll go to the server matched
by this cookie.
Hoping this helps,
Willy
