Expanding netmiko-tools

Author: Kirk Byers
Date: 2016-10-24

A few months back I created a grep-like utility based on Netmiko. At the time, I wrote an article about that utility including details on specifying the device inventory.

I recently expanded on these netmiko-tools by adding two new utilities: netmiko-show and netmiko-cfg. I would consider these two utilities experimental at this point.

Installation

The install process is straightforward. On a Linux system, do the following: 

$ pip install netmiko  # Requires Netmiko >= 1.0.0
...     # output omitted

$ git clone https://github.com/ktbyers/netmiko_tools/
...     # output omitted

$ cd netmiko_tools/netmiko_tools/
$ ls
netmiko-cfg  netmiko-grep  netmiko-show

$ pwd
/home/gituser/EP/netmiko_tools/netmiko_tools

$ export PATH=/home/gituser/EP/netmiko_tools/netmiko_tools:$PATH
$ which netmiko-cfg
~/EP/netmiko_tools/netmiko_tools/netmiko-cfg

Note, the netmiko-tools might work on MacOS, but I haven't tested them there. They likely won't work on Windows.

You also have to define an inventory which I detailed here.

At this point, I can check my inventory (which I had previously created): 

$ netmiko-show --list-devices

Devices:
----------------------------------------
arista_sw1                  (arista_eos)
arista_sw2                  (arista_eos)
arista_sw3                  (arista_eos)
arista_sw4                  (arista_eos)
arista_sw5                  (arista_eos)
arista_sw6                  (arista_eos)
arista_sw7                  (arista_eos)
arista_sw8                  (arista_eos)
bad_device                   (cisco_ios)
bad_port                     (cisco_ios)
cisco_asa                    (cisco_asa)
cisco_asa2                   (cisco_asa)
cisco_xr2                     (cisco_xr)
cisco_xrv                     (cisco_xr)
hp_procurve                (hp_procurve)
juniper_srx                    (juniper)
pynet_rtr1                   (cisco_ios)
pynet_rtr2                   (cisco_ios)


Groups:
----------------------------------------
all
arista
asa
cisco
iosxr
juniper

netmiko-show

netmiko-show allows you to retrieve show command output from a device or a group of devices. You specify the '--cmd' argument to indicate which command to execute (the default is to retrieve the running-config).

Here are some examples: 

/* Single Device */
$ netmiko-show --cmd "show run int fa4" pynet_rtr1
Building configuration...
Current configuration : 146 bytes
!
interface FastEthernet4
 description *** LAN connection (don't change) ***
 ip address 10.220.88.20 255.255.255.0
 duplex auto
 speed auto
end
/* Group of Devices */
$ netmiko-show --cmd "show ip int brief" arista
arista_sw1.txt:Interface      IP Address         Status     Protocol   MTU
arista_sw1.txt:Management1    unassigned         admin down down      1500
arista_sw1.txt:Vlan1          10.220.88.28/24    up         up        1500
arista_sw2.txt:Interface      IP Address         Status     Protocol   MTU
arista_sw2.txt:Management1    unassigned         admin down down      1500
arista_sw2.txt:Vlan1          10.220.88.29/24    up         up        1500
arista_sw3.txt:Interface      IP Address         Status     Protocol   MTU
arista_sw3.txt:Management1    unassigned         admin down down      1500
arista_sw3.txt:Vlan1          10.220.88.30/24    up         up        1500
arista_sw4.txt:Interface      IP Address         Status     Protocol   MTU
arista_sw4.txt:Management1    unassigned         admin down down      1500
arista_sw4.txt:Vlan1          10.220.88.31/24    up         up        1500
arista_sw5.txt:Interface      IP Address         Status     Protocol   MTU
arista_sw5.txt:Management1    unassigned         admin down down      1500
arista_sw5.txt:Vlan1          10.220.88.32/24    up         up        1500
arista_sw6.txt:Interface      IP Address         Status     Protocol   MTU
arista_sw6.txt:Management1    unassigned         admin down down      1500
arista_sw6.txt:Vlan1          10.220.88.33/24    up         up        1500
arista_sw7.txt:Interface      IP Address         Status     Protocol   MTU
arista_sw7.txt:Management1    unassigned         admin down down      1500
arista_sw7.txt:Vlan1          10.220.88.34/24    up         up        1500
arista_sw8.txt:Interface      IP Address         Status     Protocol   MTU
arista_sw8.txt:Management1    unassigned         admin down down      1500
arista_sw8.txt:Vlan1          10.220.88.35/24    up         up        1500

netmiko-cfg

netmiko-cfg allows you to make config changes from the Linux shell. You can make configuration changes against a single device or a group of devices.

Here are some examples: 

/* Verify current config */
$ netmiko-grep 'logging buffered' cisco
pynet_rtr1.txt:logging buffered 10000
pynet_rtr2.txt:logging buffered 20000 
/* Make change to 'cisco' group */
$ netmiko-cfg --cmd 'logging buffer 8000' cisco
pynet_rtr1.txt:config term 
pynet_rtr1.txt:Enter configuration commands, one per line.  End with CNTL/Z. 
pynet_rtr1.txt:pynet-rtr1(config)#logging buffer 8000 
pynet_rtr1.txt:pynet-rtr1(config)#end 
pynet_rtr1.txt:pynet-rtr1# 
pynet_rtr2.txt:config term 
pynet_rtr2.txt:Enter configuration commands, one per line.  End with CNTL/Z. 
pynet_rtr2.txt:pynet-rtr2(config)#logging buffer 8000 
pynet_rtr2.txt:pynet-rtr2(config)#end 
pynet_rtr2.txt:pynet-rtr2# 
/* Verify change */
$ netmiko-grep 'logging buffered' cisco
pynet_rtr1.txt:logging buffered 8000
pynet_rtr2.txt:logging buffered 8000

You can also feed configuration commands in from a file. 

$ cat test_file.txt 
ip access-list extended XTEST
  10 permit ip host 1.1.1.1 any log
  20 permit ip host 2.2.2.2 any log
/* Verify ACL isn't configured */
$ netmiko-grep 'XTEST' cisco
$
/* Configure ACL */
$ netmiko-cfg --infile test_file.txt cisco
pynet_rtr1.txt:config term 
pynet_rtr1.txt:Enter configuration commands, one per line.  End with CNTL/Z. 
pynet_rtr1.txt:pynet-rtr1(config)#ip access-list extended XTEST 
pynet_rtr1.txt:pynet-rtr1(config-ext-nacl)#  10 permit ip host 1.1.1.1 any log 
pynet_rtr1.txt:pynet-rtr1(config-ext-nacl)#  20 permit ip host 2.2.2.2 any log 
pynet_rtr1.txt:pynet-rtr1(config-ext-nacl)#end 
pynet_rtr1.txt:pynet-rtr1# 
pynet_rtr2.txt:config term 
pynet_rtr2.txt:Enter configuration commands, one per line.  End with CNTL/Z. 
pynet_rtr2.txt:pynet-rtr2(config)#ip access-list extended XTEST 
pynet_rtr2.txt:pynet-rtr2(config-ext-nacl)#  10 permit ip host 1.1.1.1 any log 
pynet_rtr2.txt:pynet-rtr2(config-ext-nacl)#  20 permit ip host 2.2.2.2 any log 
pynet_rtr2.txt:pynet-rtr2(config-ext-nacl)#end 
pynet_rtr2.txt:pynet-rtr2#
/* Verify ACL */
$ netmiko-grep 'XTEST' cisco
pynet_rtr1.txt:ip access-list extended XTEST
pynet_rtr2.txt:ip access-list extended XTEST

Finally, you can pipe commands in from stdin: 

$ echo "no ip access-list extended XTEST" | netmiko-cfg --infile - cisco
pynet_rtr1.txt:config term  
pynet_rtr1.txt:Enter configuration commands, one per line.  End with CNTL/Z. 
pynet_rtr1.txt:pynet-rtr1(config)#no ip access-list extended XTEST  
pynet_rtr1.txt:pynet-rtr1(config)#end  
pynet_rtr1.txt:pynet-rtr1#  
pynet_rtr2.txt:config term  
pynet_rtr2.txt:Enter configuration commands, one per line.  End with CNTL/Z. 
pynet_rtr2.txt:pynet-rtr2(config)#no ip access-list extended XTEST  
pynet_rtr2.txt:pynet-rtr2(config)#end  
pynet_rtr2.txt:pynet-rtr2#

Other things to note:

All of the netmiko-tools create files in ~/.netmiko/tmp. These files store the output of the commands. The files are not automatically removed after execution so you need to be aware of this from a security perspective.

netmiko-tools automatically uses threads for concurrency. netmiko-grep was tested concurrently on 1200 devices and it took between sixty to ninety seconds to complete.

You can find the Netmiko Tools here.

Kirk Byers

@kirkbyers

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