+----------+ +----------------+
| | | |
+---------->+ Database +<--+ | nginx |
| | | | | (optional) |
| +----------+ | | |
+------+------+ | +-------+--------+
| | | |
+----->| Dispatcher | <---+ | |
| | | | | |
| +------+------+ | | v
| | | | +-------+--------+
| | | | | |
| | | | | |
+---+----+ +----+---+ +----+---+ ^------+ Web server |
| | | | | | | |
| Worker | | Worker | | Worker | | |
| | | | | | +----------------+
+--------+ +--------+ +--------+