How to sync variable between servers?
Premature optimisation is the root of all evil... This being said, what you want is a cache, not an async queue. Django has a good built-in cache framework, you just have to choose your backend (redis comes to mind but there are other options)
I plan to use 3 servers(there will have a haproxy to dispath to 3 servers but I don't servey it now ) to do load balancing    
And I face a problem :
I create a object which has a function to query from database to get a list when the django start
(Because the list seldom changed but very frequently used so I inintial it at first).    
If the data changed,it will push the message to rabbitmq, and 3 servers has rabbitmq clients to get it.
But the problem is the rabbitmq listener's process is not the same with django     
How can it nortify to django process ??
Now my solution is call api(use localhost) when rabbitmq client got the changed.(so the guest can visit website and I can change the list)
But it have to bind 0.0.0.0,I am not sure it's a good idea  
What is a better way to sync between 3 servers ???