def ssh_and_exec(ip,username,passwd,cmd):

    try:
        ssh = paramiko.SSHClient()
        ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
        ssh.connect(ip,22,username,passwd,timeout=5)
        stdin,stdout,stderr=ssh.exec_command(cmd)
        if stdout != None:
            #out = stdout.readlines()
            buf = stdout.read()
            ret_list=buf.decode(‘ascii‘,‘replace‘).split(‘\n‘)
            ssh.close()
            print "ssh to %s and exec:%s ok"%(ip,cmd)
            return ret_list
        if stderr != None:
            print stderr
            ssh.close()
            return None    
    except Exception :
        print "ssh to %s login:%s passwd:%s error "%(ip,username,passwd)

out=json.dumps(policys_dict,ensure_ascii=False)