Here's some sample configurations:

   http {
       ...

       upstream cluster {
           # simple round-robin
           drizzle_server 127.0.0.1:3306 dbname=test
                password=some_pass user=monty protocol=mysql;
           drizzle_server 127.0.0.1:1234 dbname=test2
                password=pass user=bob protocol=drizzle;
       }

       upstream backend {
           drizzle_server 127.0.0.1:3306 dbname=test
                password=some_pass user=monty protocol=mysql;
       }

       server {
           location /mysql {
               set $my_sql 'select * from cats';
               drizzle_query $my_sql;

               drizzle_pass backend;
           }
           ...
       }
   }