I found no detail about the Number of users to simulate and Hatch rate in the locust documentation.
What is the relation between the two parameters?
If I have 20 clients, of each will post 1000 requests/second to the server, how should I set the two parameters to test the server?
"Hatch rate" is how quickly you want to spawn the users.
Example:
"Number of users to simulate" = 20
"Hatch rate" (user spawned / second) = 2
When you start the load test with this configuration, locust will spawn 2 new users for every second until it fulfils the total number of users to simulate (which is 20 in this case). After 10 seconds, you will have a swarm of 20 simulated users.
To control the no. of request per second, you will need to set the max_wait accordingly.