title: Errors with Locust load testing scripts - Connection aborted.', RemoteDisconnected
body: <p>I am new to Locust Load testing framework and in process of  migrating my existing Azure cloud based Performance testing C# scripts to Locust's Python based scripts. Our team almost completed migration of scripts. But during our load tests, we are getting errors as below, which fails to create new requests from the machine due to high CPU utilization or because of so many exception on Locust. We are running with Locust web based mode - details are indicated below. These scritps are working fine on smaller loads of 50 to 100 users</p>
  
  <p>"<strong>Error 1 -('Connection aborted.', RemoteDisconnected('Remote end closed connection without response',)</strong>)"</p>
  
  <p>"<strong>Error 2 : Connection pool is full, discarding connection</strong>"</p>
  
  <p>"** **Error 3 :urllib3.exceptions.NewConnectionError: : Failed to establish a new connection: [Errno 110] Connection timed out****"</p>
  
  <p>Yes, we are using UrlLibs on the utility classes . But first 2 error does seems to be of Locust.</p>
  
  <p>Our Load testing configurations  are : "<strong>3500 users at a hatch rate of 5 users per second</strong>". Running natively(no docker container) on a 8 Core , 16 Gb Linux Ubuntu Virtual machine on Azure. ulimit set as 50,000 on Linux machine.</p>
  
  <p>Please help us with your thoughts</p>
  
  <p><strong>Sample test is as below</strong></p>
  
  <pre><code>import os 
  import sys
  sys.path.append(os.environ.get('WORKDIR', os.getcwd()))
  
  from locust import HttpLocust, TaskSet, task
  from locust.wait_time import between
  
  class ContactUsBehavior(TaskSet):
  
  
      wait_time = AppUtil.get_wait_time_function(2)
  
  
      @task(1)
      def post_load_test_contact(self):
          data = { "ContactName" : "Mane"
              , "Email" : "someone@someone.com"
              , "EmailVerifaction" : "someone@someone.com"
              , "TelephoneContact" : ""
              , "PhoneNumber" : ""
              , "ContactReason" : "Other"            
              , "OtherComment" : "TEST Comments 2019-12-30"
              , "Agree" : "true"
               }
          self.client.post("app/contactform", self.client, 'Contact us submission', post_data = data)
  
  
  class UnauthenticatedUser(HttpLocust):
      task_set = ContactUsBehavior
      # host is override-able
      host = 'https://app.devurl.com/'
  </code></pre>