process

[José]

I have a farm with 4 web servers.
I want to write a client-server program to rotate logs.
Basically the server has only one file, if I run it, the server listens.
The client has 2 files, one client and another server.
If the log is greater than xxx bytes, then the client send a message to 
the server, then the server send another message to all the webservers, 
and they must to rotate logs.
I'm too new in Python and I don't know a lot of modules, so the problem 
is: how can I know which processes are running?.
I writed all, but I want that the "client server" look at the processes.
In case it's rotating logs, it must pause all. In bash it could be:

#ps ax|grep rotatelogs

But how in Python?

thanks in advance