Hi,
Le Lundi 31 Octobre 2011 17:21:02 Piavlo a écrit :
> I have been using *capture cookie* and *appsession *in one haproxy
> configuration for sticky sessions.
> The problem is that then haproxy restarted/reload or domain is migrated
> to failover server the sticky data is lost.
> Today I realised that I don't need to use sticky sessions at all in
> haproxy - what I do is setup custom session name
> different in each backend http server based on it's name and then using
> acl match on *hdr_beg(Cookie)* to direct to the correct backend
> and if Cookie is not set then send it to round robin backend that has
> all the http servers listed.
Is there any reason to use a different cookie name per server instead of using
much standard behaviour of haproxy (using cookie insert and others) ?
Your configuration would be a lot more simple and maintainable (see at the
end).
> Below is the relevant frontend & backend config.
> It works great - but there is one problem. It's is very important that
> the *maxconn* that is set in *server *will be set globally per real http
> server
> but since I now have same server http server listed twice.
> For example for lb-srv1 web server there are *lb-srv1/lb-srv1* and
> *testing_rr/lb-srv1* - it means the total maxconn for lb-srv1 is now x2
> larger.
> I could split split the maxconn between lb-srv1/lb-srv1 and
> testing_rr/lb-srv1 - so that in total it's 900 - but this will not use
> the possible 900 slots
> since there is no way to know that ratio of lb-srv1/lb-srv1 vs
> testing_rr/lb-srv1 and it's highly dynamic.
>
> Is there some trick to share the same *maxconn* for lb-srv1/lb-srv1
> testing_rr/lb-srv1
> Or something similar to*track* - that would make *server* track other
> *server*'s maxconn too? and not only health checks.
No, or not yet.
> afaiu the haproxy backends lb-srv1 & lb-srv1 cannot be load balanced
> but only chosen based on acl or as default fallback?
No.
> ------------------------------------------------------------
> frontend testing 0.0.0.0:88
> mode http
> maxconn 20000
>
> option httplog
> monitor-uri /up.html
>
> option http-server-close
> option forwardfor
> reqadd X-Forwarded-Proto:\ http
>
> acl acl-lb-srv1 hdr_beg(Cookie) lb-srv1=
> acl acl-lb-srv1-up nbsrv(lb-srv1) 1
>
> acl acl-lb-srv2 hdr_beg(Cookie) lb-srv2=
> acl acl-lb-srv2-up nbsrv(lb-srv2) 1
>
> use_backend lb-srv1 if acl-lb-srv1 acl-lb-srv1-up
> use_backend lb-srv2 if acl-lb-srv2 acl-lb-srv2-up
> default_backend testing_rr
>
> monitor fail if !acl-lb-srv1-up !acl-lb-srv2-up
>
> backend lb-srv1
> mode http
> option httpchk /up.html
> option abortonclose
>
> server lb-srv1 lb-srv1.private:82 maxconn 900 check
> inter 2000 fall 3
>
> backend lb-srv2
> mode http
> option httpchk /up.html
> option abortonclose
>
> server lb-srv2 lb-srv2.private:82 maxconn 900 check
> inter 2000 fall 3
>
> backend testing_rr
> mode http
> option httpchk /up.html
> option abortonclose
>
> balance roundrobin
> server lb-srv1 lb-srv1.private:82 maxconn 900 track
> lb-srv1/lb-srv1
> server lb-srv2 lb-srv2.private:82 maxconn 900 track
> lb-srv2/lb-srv2
> -----------------------------------------------------------
Proposed version (untested) :
------------------------------------------------------------
listen testing 0.0.0.0:88
mode http
maxconn 20000
option httplog
monitor-uri /up.html
option abortonclose
option http-server-close
option forwardfor
reqadd X-Forwarded-Proto:\ http
acl acl-lb-down nbsrv 0
monitor fail if acl-lb-down
cookie lb insert
server lb-srv1 lb-srv1.private:82 maxconn 900 cookie srv1
check inter 2000 fall 3
server lb-srv2 lb-srv2.private:82 maxconn 900 cookie srv2
check inter 2000 fall 3
-----------------------------------------------------------
--
Cyril Bonté
