LTM monitor curl -i http://10.33.20.129:1990

Here, change the values wherever needed.

b monitor application_name_http_monitor '{
   defaults from http
   interval 30
   timeout 91
   recv disable "Server Drain"
   recv "200 OK"
   send "GET / HTTP/1.0\r\nUser-Agent: BigIP Prober\r\nHost: www.url.com\r\nConnection: close\r\n\r\n"
}'

The below is to list the monitor,

b monitor application_name_http_monitor list