Exploding Juniper Devices with NAPALM

In this multi-posts series, We will deep dive into Juniper network automation and how to automate both configuration and operation for Juniper devices using different tools available such as PyEZ, NAPALM and Ansible.

if you missed the first part, Building Basic Configuration using Jinja2 Template, Please Read it first to understand the network topology that we will work on it and generate the initial configuration.

Intro to NAPALM

in this part, we will explore a python library called N.A.P.A.L.M. This is a shortcut for Network Automation and Programmability Abstraction Layer with Multi-vendor Support. It’s vendor neutral, cross-platform open source project that provides a unified API to network devices.

Multi-Vendor?! How?

NAPALM works such that it connect to network devices through SSH interface or using vendor API (API of course is much easier to execute and parse) and execute commands directly on device CLI then parse the output using TextFSM modules and regular expressions to return the final output to use in structured format (lists and dictionaries) so you could basically use the same NAPALM getters methods(get_bgp, get_interfaces,get_mac_address…etc) to connect to devices from different vendors and get the output without even knowing the vendor command.

Moreover, The returned output will be in structured format so you can easily parse it and get the needed data. This allow you to have a unified access to data from all supported vendors with a few lines of codes

Our Use Cases

I’ll implement three use cases using NAPALM. First one is to get the interfaces TX/RX Errors and discards and print it in tabular format

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Then I want to get summarized information for specific route like the next-hop, outgoing interface and protocol that advertise this route

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Finally I want to generate compliance report for the running configuration

Note: I’ll upload all scripts to my GitHub repo

“Talk is Cheap, Show me the code”  Linus Torvalds

NAPALM Installation

Step 1

we will start first by installing the napalm module in python using PIP like what we did before in netmiko

pip install napalm

 

Step 2

Then we will import the get_network_driver from the installed napalm module. This method should be inatalized with vendor name as an input in order to prepare the proper configuration for each vendor and use the correct API

from napalm import get_network_driver
junos_driver = get_network_driver("junos")

Step 3

Finally we should provide the username and password for the device that we want to connect

mx_router = junos_driver(hostname=ip,username="root",
                         password="access123")
mx_router.open()

At this moment, The NAPALM will open session to the router and we will have the ability to run multiple getters and return the data. Lets try something simple like get_facts(). This method provide a general information about the device like the hostname, number of interfaces, running version and so on. I’ll create for loop to iterate over all devices in the topology and get the same information

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Note that I’m checking the device is reachable and live before getting the data from it. The result of is_alive() function is either True or False so I could use it inside if statement

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Note that the output is structured and actually a result of many executed commands and API calls to juniper device (like “show interface terse” , “show system uptime”, “show chassis hardware detail “). This allow you to focus on development not on finding and parsing the data returned from the device.

Use Case 1: Getting interfaces with errors

Ok, Now let’s implement our first use case. As mentioned, I want to get the Rx/Tx errors per interface in Tabular format. this could be used along with some scheduled jobs to generate nicely looking reports or even trigger an event like sending email or orchestrating another configuration and so on.

I’ll use additional module called “prettytable” that generate the take care of Table format like headers, rows, spacing

First I will ask user to enter the MX IP address as an argument to my script

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Then I will create two tables with headers using the “prettytable” module. One that hold the Rx/Tx errors and the 2nd for Tx/Rx Discards (you can also create for unicast, multicast,..etc)

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Finally I’m connecting to device and query the infromation and just selecting the data that I want from the returned output then populate the table with them. I’m using “get_interfaces_counters()” to get the  needed data and also “get_interfaces()” to get the MAC address for each interface

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Result

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Use Case 2: Searching in[et0] Routing Table

The second use case is to parse the device routing table and search for specific route attributes. This is useful when you’re troubleshooting large network and want to get a summarized view for a route. Also you can use it to visualize the control plane for the routing table (but this will require some additional modules like matplotlib and networkx).

Anyways, we just need to print the next-hop, protocol and outgoing interface for the provided route. I’ll use the same script above but this time I’ll use another method called “get_route_to()

First I will add also another argument for the route

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Then I will parse the returned output and search only for the needed attributes.

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Two things worth to mention. First I wrapped the above code in “try..except” block to catch a case where the route is not exist on a target device. so instead of printeing ugly exception, I will print a custom message. Second, I choosed the first learned path “[0]”. You could enhance the script by getting the length of all route entries and iterate over it. but for sake of bevrity, I just choosed the first occurance.

 Result1

Use Case 3: Compliance Reporting

Our final use case is quite interesting! and it’s related to auditing and compliance stuff. Assume that I want to make sure a specific configuration exist in all my network devices such as TACACS servers, default routes and SNMP communities. or I want to make sure all my devices are running on a specific vendor OS version and so on

NAPALM has a cool feature that allow you to compare the returned information (either operational or in configuration) with a YAML template and if there’s a deviation from the template, it will mention that in the final report. You can check & compare ANY value that returned from device whether it’s IP addresses, interface counters, bgp peer status, OS version..etc

Moreover, You can check if a specific item is just exist regardless it’s value. for example you can check if the router-id is configured, local ASN, ipv4 on specific interface. This what we will do exactly next.

First I will define my YAML template with all values that need to verified and checked against the values inside the device

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in the above template, I’m verifiying 4 things:

1- JunOS version is “14.1R1.10”

2- There’s IP address configured under ge-0/0/0.0
3-Device has an active BGP connection and peering

4- A router-id is configured under bgp_neighbors

So I’m basically checking both operational and configuration data.

Then I will use compliance_report() function and provide the YAML file created in previous step to check

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The result will be also structured and will indicate which parts from the template are complied and which are not

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Outro

The network automation is evolving rapidly!. Previously we just had PExpect and Paramiko modules that just establish a connection then execpt & read_until specific output. Now, we have a solid modules that able to handle different vendors and return a structured output in such a way that make network engineer/developer focus on building robust network automation solution & open a door for other modules that automate the daily operation tasks for network engineer.

I hope this been informative for you and I’d like to thank you for reading

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BGP Visualization Using Python

KSA

During my Network study, I always admire the way that BGP works and operate. The black magic that handle how the packets are exit from one country (Autonomous System=ASN for short!) and enter the another without any “Boarding-Pass” or “Visa”. Not just that, but BGP strive to make the travel time and path is the shortest one amongst the available routes to destination using of exchanged path attributes between those ASN. very clever, robust and old Winking smile

But as the internet routing table grows and number of assigned ASN increase each day, I think it’s become harder to visualize the interconnection between ASNs. Everyday a new ASN is being connected to a bunch of other ASNs and it’s really hard to trace those connections with just a raw data provided by Route Glass Servers or RIRs.

So I think it’s time to involve Python to solve this problem. Basically I tried to build a python module that answer the below questions:

1- How ASNs are being connected to each other given a list of ASNs?

2- How ASNs are being connected in one country?

3- Which ASNs are considered as an Service Provider or IXP? (has more than 15 BGP peering with other ASN)

4- Which ASN is considered an Upstream to a specific ASN? That will help in defining the ASN gateway for a country for example.

5- Which ASN is considered a Downstream (Customer) to a specific Service Provider (Operator)? and how are they distributed comparing to other Service Providers?

6- Finally I need all of that in one picture, visually! You know the old say,

A picture is worth a thousand words

and those thousand words are being stored in a lot of  RIRs like RIPE and AFRNIC that provide useful BGP data publically but in raw format.

I started developing a python module to address the above questions and in two days I have a promising prototype and able to visualize the first country then later on added a capability to visualize a portion set of ASNs. Final stage is adding some console logs for troubleshooting and publishing the package into PyPI . I called it  (bgp_visualize) , Yeah, Couldn’t find a better one Open-mouthed smile.

I tried to design the bgp_visualize to work with a minimum set of possible data. For  example in case of visualizing BGP in specific country, you need to just provide the country code. However you can customize the way and look for the generated graph by providing few parameters like node_color , node_size , desired_background  and so on.

Working on Module

First you need to install it (and install python 2.7 of course if you didn’t have it already in your machine)

Using CLI

pip install bgp_visualize

Using GUI (Pycharm IDE)

Open Settings | Project Interpreter | | Add New

Then search for bgp_visualize python module and install it

Then Run the below code to visualize a set of ASNs (You can run it also from Python native IDLE if you’re using Windows OS)

from bgp_visualize import bgp_visualize_asn
ASNs= bgp_visualize_asn.bgp_visualize(asns=[8452,24835],dark=True)
ASNs.Draw()

The resulting graph will be something like below (Click on Image for better resolution) and to visualize all autonomous systems in specific country, you need to provide the country code to the object

from bgp_visualize import bgp_visualize_asn
country= bgp_visualize_asn.bgp_visualize(country='sa')
country.Draw()

There’re a lot of screenshots for different BGP graphs are available in my Github page, so please check them out!. Also you can send me your generated graph and I’ll add it to the Github

Color Map

bgp_visualize module use different colors to represent the Autonomous System role in the graph. below is the list of colors and meaning of each in the generated graph

First if AS is considered to be  a service provider or IXP, then it will be colored with one of below colors

if AS is an upstream for specific ASN, then it will be colored as blue

ASN is Downstream:

Transit or not defined

Wrapping Up

I really enjoyed working on this package!.You can use it to troubleshoot and visualize any ASN in your network or in your country and understand the upstreams and downstreams for each one and easily identify the service providers, All in one graph!

For me, I had that idea long time ago to visualize every ASN, every connection, every prefix in the planet and draw them in nice and presentable way and I think this package is a good start, That’s my dream!.

Finally , I hope this has been informative for your and I’d like to thank you for reading.

Building Python Development Station

my guide to build a python development VM on your local windows machine to combine both the efficiency of linux and the usability of windows laptop – I use pycharm as an example of python IDE but you can use any IDE that support the remote deployment.

For more info about remote deployment function please see the below link

 

 

Remote Deployment using Pycharm

Have you ever wanted to develop a Python or Web application for Linux from your laptop running Windows 7 or MAC OS X? Do you want to run your code that  will be published to whole world but afraid from the dependencies mismatch between your laptop and   production server?

Guess what: all of this is possible with the remote development features already available in PyCharm.

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