Как и когда мы применяем автоматизацию в сети

ИТ-инфраструктуры становятся все более сложными, теперь мы обычно работаем с десятками и сотнями коммутаторов, маршрутизаторов и межсетевых экранов.

Если нам нужно применить одну и ту же команду к нескольким устройствам, то проще всего будет ansible.

Если нам нужно применить одну и ту же команду, но с разными параметрами, то в этом случае Python и netmiko пригодятся.

Используя ansible, мы можем опрашивать несколько коммутаторов несколькими разными командами и записывать вывод команд в текстовые файлы, но с Python и netmiko мы можем объединить вывод нескольких разных команд, записав только нужную нам информацию в один выходной CSV-файл.

Почему CSV? CSV-файл удобен, потому что мы можем открыть его в Excel, и легко скрыть ненужные нам столбцы, сгруппировать или упорядочить по нужным нам столбцам.

Если мы будем ежедневно создавать один такой файл со всех коммутаторов, мы легко сможем увидеть разницу в состоянии подключенных устройств, просто открыв два файла в редакторе Notepad++ в режиме сравнения.

Я объединил три команды, которые мы обычно используем для записи и отслеживания состояния всех коммутаторов и всех подключенных устройств.

Вот команды:

• show interface status

• show mac address-table

• show cdp neighbor

Моя программа на Python обращается ко всем коммутаторам из набора, выполняет все три команды и объединяет вывод всех трех команд в один файл.
Теперь нам не нужно подключаться к каждому коммутатору отдельно и выполнять все три команды одну за другой.

Для демонстрационных целей я создал очень простую инфраструктуру, состоящую из двух коммутаторов и нескольких подключенных устройств.

Выходной файл выглядит так

python программа

#!/usr/bin/python3 #   usage " python cisco_switch_info_to_csv.py --hosts_file hosts --group sw1 "         define set of switches  import yaml, argparse, csv, subprocess from netmiko import ConnectHandler  def parse_arguments():                                     # to parse command-line arguments     parser = argparse.ArgumentParser(description = ' Netmiko Script to Connect to Routers and Run Commands ')     parser.add_argument('--hosts_file', required=True, help = ' Path to the Ansible hosts file ')     parser.add_argument('--group', required=True, help = ' Group of routers to connect to from Ansible hosts file ')     return parser.parse_args()  def ping_ip(ip_address):                                   # Use ping command to check if switch alive     param = '-c'                                           # for linux os     command = ['ping', param, '2', ip_address]             # Build the ping command     try:         subprocess.check_output(command, stderr=subprocess.STDOUT, universal_newlines=True)    # Execute the ping command         return "yes"     except subprocess.CalledProcessError:         return "no"  ###########         Main function def main():     args = parse_arguments()                               # Parse command-line arguments     with open(args.hosts_file, 'r') as file:               # Load ansible hosts file in yaml format         hosts_data = yaml.safe_load(file)     global_vars = hosts_data['all']['vars']                # Extract global variables     # Extract router details for the specified group     if args.group not in hosts_data:         print(f"Group {args.group} not found in hosts file.")         return     routers = hosts_data[args.group]['hosts']              # Extract group of devices      output_filed  = args.group + '_inter_des.csv'          #     output_filec  = args.group + '_inter_cdp.csv'          #     output_filema = args.group + '_inter_mac.csv'          #     STRd = "Hostname,IP_address,Interface,State,Description,Vlan"    # column names status     with open(output_filed, "w", newline="") as out_filed:         writer = csv.writer(out_filed)         out_filed.write(STRd)         out_filed.write('\n')     STRc = "Hostname,IP_address,Interface,New_Description"           # column names cdp     with open(output_filec, "w", newline="") as out_filec:         writer = csv.writer(out_filec)         out_filec.write(STRc)         out_filec.write('\n')     STRm = "Hostname,IP_address,Interface,mac,vlan"                  # column names mac     with open(output_filema, "w", newline="") as out_filema:         writer = csv.writer(out_filema)         out_filema.write(STRm)         out_filema.write('\n') # Connect to each switch and execute the specified commands     for router_name, router_info in routers.items():                 # loop for each switch in group         if ping_ip(router_info['ansible_host']) == "no":             # check if host alive              print( ' switch offline --------- ', router_name,'  ',router_info['ansible_host'])             continue         else:              print( ' switch  online --------- ', router_name,'  ',router_info['ansible_host'])                  de_type = ''         if global_vars['ansible_network_os'] == 'ios':               # check if cisco ios             de_type = 'cisco_ios'         netmiko_connection = {                                       # Create Netmiko connection dictionary             'device_type': de_type,             'host': router_info['ansible_host'],             'username': global_vars['ansible_user'],             'password': global_vars['ansible_password'],             'secret': global_vars['ansible_become_password'],         }          connection = ConnectHandler(**netmiko_connection)                  # Establish SSH connection         connection.enable()                                                # Enter enable mode           comm1 = 'show int status | begin Port'         comm2 = 'show cdp neighb | begin Device'         comm3 = 'show mac addres  dynam'         outputd1 = connection.send_command(comm1)                          # Execute the specified command         if (outputd1.replace(' ', '') == ''):             print(router_info['ansible_host'],'  empty -- router  , continue with next')             continue                                                       # exclude router from switches         outputd2  = connection.send_command(comm2)         outputd31 = connection.send_command(comm3, use_textfsm=True)       # mac textfsm         connection.disconnect()                                            # Disconnect from device         print(f"  ------------ Output from {router_name} ({router_info['ansible_host']}):")           # Print the output         print('   mac textfsm ------- ', type(outputd31))         print(outputd31)                                                   # mac textfsm         print("  ------------")                                  lines = outputd1.strip().split('\n')                           ####     parse 'show interface status'         lines = lines[1:]         for line in lines:             if (line == '') or (line.startswith("Port")):                 continue             swi=router_name             ipad= router_info['ansible_host']             por=line[:9].replace(' ', '')                                # port             sta =  line[29:41].replace(' ', '')                          # interface status connected or notconnect             des =  line[10:28].replace(' ', '')                          # existing description             vla =  line[42:47].replace(' ', '')                          # vlan             print("switch ",swi," port ",por, 'state ',sta," Descr ",des," vlan ", vla )             STR = swi + "," + ipad + "," + por +"," + sta +"," + des + "," + vla             # +","  # with ip             with open(output_filed, 'a') as f:                           # write to file                 f.write(STR)                 f.write('\n')         lines1 = outputd2.strip().split('\n')                           ####     parse 'show cdp n'         lines1 = lines1[1:]                                                # This correctly removes the first line (header)          for line in lines1:             if (line == '') or (line.startswith("Devic")):                 continue              rlin1 =  line[:16]             dot_position = rlin1.find('.')             rlin2 = rlin1[:dot_position]                                   # remove domain name from switch name             rlin =  rlin2 + '|' + line[58:67] + '|' + line[68:]            # new interface description             ndes = rlin.replace(' ', '')                                   # remove all spaces             por=line[17:33]             por1 = por[0:2]+por[3:33]                                      # remove 3rd char from port name             por=por1.replace(' ', '')             swi=router_name             ipad= router_info['ansible_host']             print("switch ",swi," port ",por, " Descr ", ndes )             STRc = swi + "," + ipad + "," + por +"," + ndes                # switch name with ip             with open(output_filec, 'a') as f:                 f.write(STRc)                 f.write('\n')         print(f"  ------------ end")          ######        ---------------------------------------------      ####     parse 'show mac address-table' texfsm               for entry in outputd31:                                                      # Remove square brackets from 'destination_port' values             entry['destination_port'] = entry['destination_port'][0]         outputd31_sorted = sorted(outputd31, key=lambda x: x['destination_port'])    # Sort the list by 'destination_port'         unique_data31 = []         ports_seen = {}          # Count occurrences of each port         for entry in outputd31_sorted:             port = entry['destination_port']             if port in ports_seen:                 ports_seen[port] += 1             else:                 ports_seen[port] = 1          # Keep only ports that appear once         unique_data31 = [entry for entry in outputd31_sorted if ports_seen[entry['destination_port']] == 1]          # Output the result         for entry in unique_data31:             print(entry)             STRm = swi + "," + ipad + "," +entry['destination_port'] + "," +entry['destination_address'] + "," + entry['vlan_id']            #             with open(output_filema, 'a') as f:                 f.write(STRm)                 f.write('\n')        output_filem = args.group + '_merg.csv'         #    mrge 2 in 1         with open(output_filed, mode='r') as file:         reader = csv.DictReader(file)         sw_inter_des_data = list(reader)            # Read descr file into a list of dictionaries     with open(output_filec, mode='r') as file:         reader = csv.DictReader(file)         sw_inter_cdp_data = list(reader)            # Read cdp file into a list of dictionaries     with open(output_filema, mode='r') as file:         reader = csv.DictReader(file)         sw_inter_mac_data = list(reader)            # Read mac file into a list of dictionaries     cdp_lookup = {                               # Create a lookup dictionary for sw_inter_cdp_data based on Hostname, IP_address, and Interface         (row['Hostname'], row['IP_address'], row['Interface']): row['New_Description']         for row in sw_inter_cdp_data     }     mac_lookup = {                               # Create a lookup dictionary for sw_inter_cdp_data based on Hostname, IP_address, and Interface         (row['Hostname'], row['IP_address'], row['Interface']): row['mac']         for row in sw_inter_mac_data     }     for row in sw_inter_des_data:         key = (row['Hostname'], row['IP_address'], row['Interface'])         row['New_Description'] = cdp_lookup.get(key, '')       # Add the New_Description to sw_inter_des_data         row['mac']             = mac_lookup.get(key, '')       # Add mac     with open(output_filem, mode='w', newline='') as file:     # Write the updated data to a new CSV file         fieldnames = sw_inter_des_data[0].keys()         writer = csv.DictWriter(file, fieldnames=fieldnames)         writer.writeheader()         writer.writerows(sw_inter_des_data)     print("New CSV file with added New_Description column has been created as ", args.group , '_merg.csv')  #################### Entry point of the main if __name__ == '__main__':     main()