why it report a error RequirementParseError invalid requirement parse error at '' at sometimes when using newest paramiko 2.0.2 of python 2.7.12

Question

1. I use python 2.7.12 and newest paramiko 2.0.2, and run a script which ssh login many linux server concurrently.

   sometimes it runs very well, but sometimes it will report the following weird error:

   **no handers could be found for logger 'paramiko.transport'

   .....

   Exception in thread Thread-2

   .....

   .....

   RequirementParseError invalid requirement parse error at ''**

2. the script is shown in below:

   anybody can help me?

   Thanks in advance with for any help.

   #! ~/python2.7.12/bin/python
   import paramiko
   import threading
   def ssh2(ip,username,passwd,cmd):
       try:
           ssh = paramiko.SSHClient()
           ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
           ssh.connect(ip,22,username,passwd,timeout=5)
           for m in cmd:
               stdin, stdout, stderr = ssh.exec_command(m)
               out = stdout.readlines()
               for o in out:
                   print o,
           print '%s\tOK\n'%(ip)
           ssh.close()
       except :
           print '%s\tError\n'%(ip)      
   
   if __name__=='__main__':
       cmd = ['uptime','free -g']
       username = "usera"  
       passwd   = "wordad"    
       threads  = []   
       print "Begin......"
       for i in range(10,154):
           ip = '10.16.2.'+str(i)
           a=threading.Thread(target=ssh2,args=(ip,username,passwd,cmd))
           threads.append(a)
   
       for i in threads:
           i.start()
   
       for i in threads:
           i.join()         
   

Answer 1

This workaround worked for me. Change from a

concurrent.futures.ThreadPoolExecutor

to a:

concurrent.futures.ProcessPoolExecutor

See full context