Introduction

pyntc is an open source multi-vendor Python library that establishes a common framework for working with different network APIs & device types (including IOS devices)

It's main purpose to is to simplify the execution of common tasks including:

• Executing commands
• Copying files
• Upgrading devices
• Rebooting devices
• Saving / Backing Up Configs

Supported Platforms

• Cisco IOS platforms - uses SSH (netmiko)
• Cisco NX-OS - uses pynxos (NX-API)
• Arista EOS - uses pyeapi (eAPI)
• Juniper Junos - uses PyEz (NETCONF)

It is a multi-vendor AND multi-API library.

Installing pyntc

Option 1:

sudo pip install ntc` or `pip install ntc --upgrade)

Option 2:

git clone https://github.com/networktocode/pyntc.git
cd pyntc
sudo python setup.py install

Getting Started with pyntc

There are two ways to get started with pyntc.

The first way is to use the ntc_device object. Just pass in all required parameters to the object to initialize your device. Here we are showing the import, but renaming the object to NTC.

>>> from pyntc import ntc_device as NTC
>>> 

Like many libraries, we need to pass in the host/IP and credentials. Because this is a multi-vendor/API library, we also use the device_type parameter to identify which device we are building an instance of.

pyntc currently supports four device types:

• cisco_ios_ssh
• cisco_nxos_nxapi
• arista_eos_eapi
• juniper_junos_netconf

The example below shows how to build a device object when working with a Cisco IOS router.

>>> # CREATE DEVICE OBJECT FOR AN IOS DEVICE
>>> 
>>> csr1 = NTC(host='csr1', username='ntc', password='ntc123', device_type='cisco_ios_ssh')
>>>

And here is an object for a Cisco Nexus device:

>>> # CREATE DEVICE OBJECT FOR A NEXUS DEVICE
>>> 
>>> nxs1 = NTC(host='nxos-spine1', username='ntc', password='ntc123', device_type='cisco_nxos_nxapi')
>>> 

The second way to get started with pyntc is to use the pyntc configuration file. This was modeled after Arista's .eapi.conf file. Our file is called .ntc.conf

This simplifies creating device objects since you no longer need to specify credentials and other device specific parameters when you build the device object. Instead, they are stored in the conf file.

pyntc Configration File

• filename: .ntc.conf
• Priority of locating the conf file:
  • filename param in ntc_device_by_name
  • Environment Variable aka PYNTC_CONF
  • Home directory .ntc.conf
• Specify device_type and a name
• host is not required if the name is the device's FQDN
• Four supported device types: cisco_nxos_nxapi, cisco_ios_ssh, arista_eos_eapi, and juniper_junos_netconf

Here is an example .ntc.conf file:

[cisco_nxos_nxapi:nxos-spine1]
host: 31.220.64.117
username: ntc
password: ntc123
transport: http

[cisco_ios_ssh:csr1]
host: 176.126.88.94
username: ntc
password: ntc123
port: 22

[juniper_junos_netconf:vmx1]
host: 176.126.88.99
username: ntc
password: ntc123

We can now build device objects just by referencing the name of the device from the conf file.

>>> from pyntc import ntc_device_by_name as NTCNAME
>>> 
>>> csr1 = NTCNAME('csr1')
>>>
>>> nxs1 = NTCNAME('nxos-spine1')
>>> 
>>> vmx1 = NTCNAME('vmx1')

Once the device object is creating using either ntc_device or ntc_device_by_name, you can start using the built-in device methods in pyntc.

Note: the only method and property not supported on all devices is install_os. It is not supported on Juniper Junos devices.

Gathering Facts

• Use facts device property

On a Nexus device:

>>> nxs1 = NTCNAME('nxos-spine1')
>>> 
>>> nxs1.facts
{'vendor': 'cisco', 'interfaces': [], u'hostname': 'nxos-spine1', u'os_version': '7.1(0)D1(1) [build 7.2(0)ZD(0.17)]', u'serial_number': 'TM600C2833B', u'model': 'NX-OSv Chassis', 'vlans': ['1']}
>>> 
>>> print json.dumps(nxs1.facts, indent=4)
{
    "vendor": "cisco", 
    "interfaces": [], 
    "hostname": "nxos-spine1", 
    "os_version": "7.1(0)D1(1) [build 7.2(0)ZD(0.17)]", 
    "serial_number": "TM600C2833B", 
    "model": "NX-OSv Chassis", 
    "vlans": [
        "1"
    ]
}

On an IOS device:

>>> csr1 = NTCNAME('csr1')
>>> 
>>> print json.dumps(csr1.facts, indent=4)
{
    "uptime": 87060, 
    "vendor": "cisco", 
    "uptime_string": "01:00:11:00", 
    "interfaces": [
        "GigabitEthernet1", 
        "GigabitEthernet2", 
        "GigabitEthernet3", 
        "GigabitEthernet4", 
        "Loopback100"
    ], 
    "hostname": "csr1", 
    "ios": {
        "config_register": "0x2102"
    }, 
    "fqdn": "N/A", 
    "os_version": "15.5(1)S1", 
    "serial_number": "", 
    "model": "CSR1000V", 
    "vlans": []
}

Sending Show Commands

• show method
• Note: API enabled devices return JSON by default

>>> nxs1.show('show hostname')
{'hostname': 'nxos-spine1'}
>>>

• Use raw_text=True to get unstructured data from the device

>>> nxs1.show('show hostname', raw_text=True)
'nxos-spine1 \n'
>>> 

Sending Multiple Commands

• show_list method

>>> cmds = ['show hostname', 'show run int Eth2/1']

>>> data = nxs1.show_list(cmds, raw_text=True)

>>> for d in data:
...   print d
... 
nxos-spine1 

!Command: show running-config interface Ethernet2/1
!Time: Wed Jan  6 18:10:01 2016
version 7.1(0)D1(1)
interface Ethernet2/1
  switchport
  no shutdown

Config Commands

• Use config and config_list

>>> csr1.config('hostname testname')
>>> 

>>> csr1.config_list(['interface Gi3', 'shutdown'])
>>> 

Viewing Running/Startup Configs

• Use running_config and start_up device properties
  • Only showing partial config (manually shortened for this slide)

>>> run = csr1.running_config
>>> 
>>> print run
Building configuration...

Current configuration : 2062 bytes
!
! Last configuration change at 18:26:59 UTC Wed Jan 6 2016 by ntc
!
version 15.5
service timestamps debug datetime msec

lldp run
cdp run
!
ip scp server enable
!
interface GigabitEthernet1
 ip address 10.0.0.50 255.255.255.0
 cdp enable

Copying files

• file_copy method

>>> devices = [csr1, nxs1]
>>> 
>>> for device in devices:
...   device.file_copy('newconfig.cfg')
...
>>>

Save Configs

• save method

copy run start for Cisco/Arista and commit for Juniper

>>> csr1.save()
True

You can also do the equivalent of copy running-config <filename> by specifying a filename:

>>> csr1.save('mynewconfig.cfg')
True

Backup Configs

Backup current running configuration and store it locally

>>> csr1.backup_running_config('csr1.cfg')
>>> 

Reboot

Reboot target device

Parameters:

• timer=0 by default
• confirm=False by default

>>> csr1.reboot(confirm=True)
>>> 

Installing Operating Systems

>>> device.install_os('nxos.7.0.3.I2.1.bin')
>>> 

Full workflow example:

>>> device.file_copy('nxos.7.0.3.I2.1.bin')
>>> device.install_os('nxos.7.0.3.I2.1.bin')
>>> device.save()
>>> device.reboot()          # IF NEEDED, NXOS automatically reboots
>>>