Automating Network Configurations with Jinja2 and Python: A Step-by-Step Guide

 In this post, I worked on collecting a code that works with Jinja template.

the nice thing in working with Jinja is that you can have baseline configs that will be used to all devices and also have variables that will be changed according to your need.

for example: in each device which can be a router, you will have:

1. southbound links to switches and let's assume an interface used for this G1/0/48

2. you have NTP servers to be configured on these routers

3. hostnames

4.routing protocol

.......etc.

all these can be variable in Jinja template which we can use along with python to generate configs. and maybe even later we can use to push to network nodes.

this can automate our work, on the longterm this can make our job easier and more consistent.

let's start by making a directory which we can call routers_configs

in this directory we will have three files:

1. jinja file which is our router configs template and it should have the following:

file name is >> cisco_template.j2

as you can see in template below, you can have a complete configuration file ready and change the parts that you want them to be replaced from your CSV file with the {{ variable }} as below>>

hostname {{ router_name }}

ntp server {{ ntp_ip }}

interface loopback 0

ip address {{ ip_address }} 255.255.255.255

router {{ routing_pro }}

int gig {{ int_number }}

2. devices information, which can be a CSV file where you have saved your new devices list and information that you will add to these devices. 

the file can be used as below with comma to separate the rows.

router-bgd, 192.68.1.2, 2.2.2.2, ospf 1, 1/0/48

router-suly, 172.16.1.1, 1.1.1.1, ospf 1, 1/0/48

rtr-erbil, 10.0.0.1, 1.1.1.1, ospf 1, 1/0/48

router-bgd2, 192.68.1.3, 2.2.2.2, ospf 1, 1/0/48

router-suly2, 172.16.1.2, 1.1.1.1, ospf 1, 1/0/48

rtr-erbil2, 10.0.0.2, 1.1.1.1, ospf 1, 1/0/48

3. file is the python code that we will use to render the information in these two files and printout the configs to an external text files for each device. and we will name the file as ciscojinja.py

import csv

from jinja2 import Environment, FileSystemLoader

#these must always added

file_loader = FileSystemLoader('.') #check this directory to find jinja template

#load environment

env = Environment(loader=file_loader)

template = env.get_template('cisco_template.j2') #find the jinja file and get it

with open ('info.csv') as info_source:

csv_file = csv.reader(info_source)

for row in csv_file:

csv_router_name = row[0]

csv_ip = row[1]

csv_ntp_server = row[2]

routing_protocol = row[3]

interface_slot = row[4]

output = template.render(router_name=csv_router_name, ip_address=csv_ip,

ntp_ip=csv_ntp_server,

routing_pro=routing_protocol,

int_number=interface_slot) #these names must be compatible with jinja template names

with open(csv_router_name + '.txt', 'w') as configs:

configs.write(output)

when you run the python code, you will notice that other text files will be generated that contain configuration rendered from the CSV data. check below:

you can copy these and iterate to what else you need. next will be added more jinja templates to specific parts of configs, for example: jinja template for bgp configs only or ospf only or ACL's and prefixes.

Hope this is helpful.

Automating Firewall Access with SSH Keys for Seamless Network Management

In this post we are going to talk about how to login to the firewall using public key generated from your Linux machine (Network Jumper box) which can be useful in case you want to push scripts to the firewall without the need to authenticate with username and a password, let's go:

1. generate the key

samer@Samers-MacBook-Pro ~ % ssh-keygen

Generating public/private rsa key pair.

Enter file in which to save the key (/Users/samer/.ssh/id_rsa):

/Users/samer/.ssh/id_rsa already exists.

Overwrite (y/n)? y

Enter passphrase (empty for no passphrase): press enter

Enter same passphrase again: press enter 

Your identification has been saved in /Users/samer/.ssh/id_rsa

Your public key has been saved in /Users/samer/.ssh/id_rsa.pub

here you have created the key on your machine, and you can check it using the command $ls ~/.ssh/ which will view the existence of the generated keys in your hidden directory  of ssh.

samer@Samers-MacBook-Pro ~ % ls ~/.ssh
id_ed25519 id_ed25519.pub id_rsa id_rsa.pub known_hosts

 now you need to copy the public key to the server or firewall or router you want to access and you can do this using:

1. SCP or....

2. importing it on the firewall using GUI.

press OK, then COMMIT.

now you can check access and as you can see below image, the user we used to access was api, if you don't specify the user, the terminal will use your machine name which is in this case "samer" and authentication will fail so we will use the same user "api" but no password will be prompted:

so the main idea here is that as network automation is important and it is recommended that you use LINUX machine as jumping box to do your scripts/codes to do your automation and programming tasks.

so it is better to use the SSH generated keys to login to devices, this will make running automated tasks easier and does not require user/password entering. (for example: no need to input password for netmiko while running a python script).

running CRON-TAB tasks that will also make access easier while it is still secure.

hope this was helpful.

Configuring Cisco Call Manager for Conference Call Setup

 In this post I will be configuring Cisco Call manager to allow users to join a phone call to make a conference.

follow the following steps:

1. Login to CM Administration page

2. Go to Call Routing > Conference NOW

3. Add new > and configure something similar to the following:

Add a number that you will be dialing to join a conference like (*3000)

select the route partition, and choose the Music on Hold option if want to.

now note that for the number that you want to dial a conference with, it must have the following configs under End User.

Go to > End User > search a number like 1169 in my screenshot.

Add the following because it is really important: self-service user ID

 

 

without this step you will not be able to configure the one below:

 

Enable End user to Host Conference now must be ticked.

then add the access code that you will have to enter when dialing *3000

Now all you have to do is make a call using the extension: 1169 then use another extension and dial *3000, once you here the reply machine asking for the meeting number you must enter 1169 then you will have to enter the Attendees Access Code 123123

and you will join the call.

hope this helps!

Samer R. Saleem