[Freeswitch-users] Load balancing solution using pure FreeSWITCH

[Tihomir Culjaga]

this is something you took from Mera .. isn't it ? :)



On Tue, Mar 16, 2010 at 1:04 PM, Vitalii Colosov <vetali100 at gmail.com>wrote:

> Hi dear FS community,
>
> After a brief analysis of 2 solutions using OpenSIPS and Kamailio (
> http://www.opensips.org/html/docs/modules/devel/load_balancer.html#id226109) and (
> http://wiki.freeswitch.org/wiki/SBC_Setup) I decided to implement my own
> solution using ONLY FreeSWITCH and ONLY 1 table of any database server (we
> use MySQL).
>
> It works on few of our servers right now without any issues.
>
> Feel free to reuse / improve it or provide your comments if you see
> something wrong with it.
>
>
> We have one routing server (RS) and several Media Servers (MS).
> FreeSWITCH is installed on each server in default configuration.
>
> --> MS_1
> RS  --> MS_2
> --> MS_N
>
>
> (Failover can be implemented by adding one more routing server, but this is
> out of scope of current description).
>

routing server is your single point of failure, you should make two of them
in active/standby mode. What about registered endpoints ? ... where do you
register them?.... you should have a DB replication in order to have the
"registered context" distributed between both routing servers


So, i'd suggest to bring up a LAN_HA and have a floating address between
your routing servers.... of course the you should be using ODBC in the core
to have registrations on both servers.




>
> Routing server routes calls to media servers based on logic that you can
> easily define.
> (Generally speaking, Routing server can route part of the calls onto
> itself, but to simplify let's say that it will route only to Media Servers).
>
> you will be loosing calls on the on the MS if it goes down ... maybe there
is a way to "replace" media resource for that calls and keep them going even
after the MS went down.



>
> Routing server is used to register subscribers (it will have directory
> files
> ./freeswitch/conf/directory/default/10001whatever.xml-99999whatever.xml).
> Media servers do NOT contain files with users (security issue? probably
> should be managed on dialplan stage of media servers by comparing ip
> addresses of requests).
>
>
consider ODBC in the core!


>
> The whole routing can be presented by the following chain:
>
> Call arrives into Default context-->RS default dialplan-->Lua script-->PHP
> script to get destination MEDIA SERVER IP-->back to Lua script-->Bridge
> "sofia/external/" to determined MS IP address-->[Bridge to fail over media
> server, optionally]-->End
>
> Let's say we need to route all international calls based on less loaded
> server (other logic can be easily implemented in PHP script as well).
>
> *1. RS Dialplan: default.xml*
> <include>
>         <extension name="route">
>                 <condition field="destination_number"
> expression="^(00)(\d+)">
>                         <action application="lua" data="route.lua $2"/>
>                 </condition>
>         </extension>
> </include>
>
>
> *2. RS Lua script: route.lua*
> called_number = argv[1]; //without "00"
> api = freeswitch.API();
> server_ip_address = api:executeString("curl
> http://localhost/get_server_ip.php);
> forwarding_session_string =
> "sofia/external/"..called_number.."@"..server_ip_address;
> session:setVariable("bypass_media", "true"); //described below!!!
> session:execute("bridge",forwarding_session_string);
>
>
do your bridging in the dialplan not from a script... you will get better
performances!




> *3. PHP script: get_server_ip.php*
> <<<  ANY PHP CODE THAT WILL QUERY COMMON DATABASE AND WILL DETERMINE LESS
> LOADED AT THE MOMENT SERVER>>>
> die($less_loaded_server_ip);
>
>
> All Media Servers should provide information about their current load into
> one common database (dedicated server or routing server can be used for
> database).
> If you use scripts you can update this table on starting a call and after
> call finished.
> Or you can create a job that will query FreeSWITCH and will update the
> database every, say, 10 seconds.
>
>
> Basically that's all (really!)
> I beleive it can be used for most general purpose scenarios without need of
> third-party tools.
>
> P.S.
> The only problem we had from the beginning was that RTP media traffic was
> passing thru both servers: RS and Media Server.
> But after we added the following command to the routing script, RTP media
> traffic started to pass only thru Media server, making RS almost free.
> session:setVariable("bypass_media", "true");
>
>
>
anyhow it is a good start ... with a custom module for media server
"kepalive" and resource migration it could be a great solution.


T.
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