Cisco ACI: Deployment With Python

Let’s see how to automate the Cisco ACI deployment using Python!! 😊

Why Python?

I know…I know…you are thinking something like: “Why did Riccardo create a python script to do that and he didn’t just use Ansible or Terraform?”…
Well, the reply is pretty easy: I wanted to do it with Python and I did. I found the python library in the Cisco DevNet Cert Guide and I decided to try it…. You know me, I’m sooooo curious πŸ˜‰

Python Library

As mentioned before, I used a specific Python library to build this script called “acitoolkit”, you can find here the GitHub page with more information.
If you want to use this library I strongly recommend you to read, or at least to know that there are these documents:

The ACI Toolkit is a set of python libraries that allow basic configuration of the Cisco APIC controller. It is intended to allow users to quickly begin using the REST API and accelerate the learning curve necessary to begin using the APIC.

Installation

Requirements

pip3 install setuptools

Downloading

I’ll show you how to install it on Ubuntu if you have git installed. Please clone the repository:

git clone https://github.com/datacenter/acitoolkit.git
cd acitoolkit/
python3 setup.py install

Great! We’re ready now 😊

Cisco ACI Sandbox (THANKS CISCO πŸ™)

Ladies and gentlemen, Cisco offers us access to the Cisco ACI Sandbox! Here is the link: https://sandboxapicdc.cisco.com

Today, 06/18/2022 you can use the following username/password to log in:

  • username: admin
  • password: !v3G@!4@Y

If you are unable to log into the APIC, please look for new credentials on the web.
With this machine, you can test lots of stuff! Configuration, API, script, new features and so on πŸ˜‰

First Python script: Retrive data from APIC

This first script is very easy but it can help you to understand how the libraries work!
We’ll connect to the APIC and we want to print all the configured tenants. You can find the script on my GitHub page: https://github.com/thetechguy-it/Cisco-ACI/blob/master/get_tenant.py

The script is called: get_tenant.py

from acitoolkit.acitoolkit import *
import credentials

session = Session(credentials.url, credentials.user, credentials.pwd)
session.login()

tenantlist = Tenant.get(session)
for tenants in tenantlist:
print(tenants.name)

We’re using the “acitoolkit” library to retrieve data from APIC. I decided to store some variables such as URL, USER and PSW in a different file called “credentials.py” that this script has imported.
Usually is always a good choice to store this kind of variable (credentials) into a different file, so you can share the script without any personal data.

However, the output is something like that:
one

As we can see, there are 3 default tenants: infra, common and mgmt plus 4 user-created tenants: Heroes, SnV, oneaciapp and DMZ (some of you guys created this one…happy lab! 😊).
Ok, now we can move on and create our Tenant!

Second Python script: Tenant Creation

As always, all the scripts are stored on my GitHub account

from acitoolkit.acitoolkit import *
import credentials

session = Session(credentials.url, credentials.user, credentials.pwd)
session.login()
new_tenant = “THETECHGUY”
tenant = Tenant(new_tenant)
tenant.push_to_apic(session)

print(“Configuration applied!\nNow let’s check the Tenant list:")

tenantlist = Tenant.get(session)
for tenants in tenantlist:
print(tenants.name)
if tenant.name == new_tenant:
print(f"Congrats! Configuration applied successfully!\nTenant called {new_tenant} is in the list”)
else:
print(f"Sorry! Tenant called {new_tenant} is not in the list, check your code and try again")

With this script I created a new tenant called “THETECHGUY” and checked the configuration has been applied correctly! 😊
To do that, I retrieve the tenant list thank to the get() function and compare it with the variable “new_tenant” (where the real Tenant name is stored).
If everything is OK I’ll receive this output:
“Congrats! Configuration applied successfully!
Tenant called THETECHGUY is in the list”

two

Please note that the configuration changes are possible thanks to the .push_to_apic() function.

As you can see from the image, now the “THETECHGUY” Tenant is on the tenant list! Let’s check also via GUI :
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Third Python script: VRF, BD and EPG Creation

Now that we discovered how to retrieve the tenant list and how to create a tenant, we need to do one more step: Create VRF, BD and EPG.
This is the main commands:

  • tenant = Tenant(new_tenant)
  • app = AppProfile(“Application Profile name”, tenant) : Denife the new application profile
  • vrf = Context(“VRF Name”, tenant) : Define the new VRF
  • bd = BridgeDomain(“BridgeDomain name”, tenant) : Define the new BridgeDomain
  • epg = EPG(“EPG name”, app) : Define the new EndPoingGroup
  • bd.add_context(vrf) : Associate the BridgeDomain to the VRF
  • epg.add_bd(bd) : Associate the EndpoingGroup to the BridgeDomain

With this information and with the official documentation:

We can go ahead and create the script:

from acitoolkit.acitoolkit import *
import credentials

session = Session(credentials.url, credentials.user, credentials.pwd)
session.login()

new_tenant = “THETECHGUY”
new_app = “APP1”
new_vrf = “VRF1”
new_bd = “BD1”
new_epg = “EPG1”

tenant = Tenant(new_tenant)
app = AppProfile(new_app, tenant)
vrf = Context(new_vrf, tenant)
bd = BridgeDomain(new_bd, tenant)
epg = EPG(new_epg, app)
bd.add_context(vrf)
epg.add_bd(bd)

print(f"I’m going to push the following parameters\nTenant: {tenant}\nApplication Profile: {app}\nVRF: {vrf}\nBridge Domain: {bd}\nEPG: {epg}\n")
tenant.push_to_apic(session)
print(“Configuration applied, please verify it through GUI”)

Output:
four

Now, let’s check the GUI:
five

Perfect guys, now the final step: Put all this information together!

Fourth Python script: Create a full tenant

Ok, it’s time to simplify our job πŸ˜‰
I created three different files:

  • credentials.py –> APIC credentials
  • cfg_tenantFULL_direct.py –> direct means without human interaction
  • data.txt

Let’s talk about data.txt.
Usually, when you’re creating ACI documentation there is some information that you must have in your head:

  • Tenant Name
  • Application Profile
  • VRF Name
  • BridgeDomain Name
  • BridgeDomain Subnet
  • EPG Name

Using the migration approach called “Network-Centric” you’re doing the following association: 1 VLAN = 1 BD = 1 EPG.
With this in mind, you can understand now the reason why I put the following values into the file called “data.txt”:

TENANT APP. PROF VRF BD BD SUBNET EPG
THETECHGUY App1 VRF1 BD1 10.10.10.1/24 EPG1
THETECHGUY App1 VRF1 BD2 10.10.20.1/24 EPG2
THETECHGUY App2 VRF2 BD3 EPG3
THETECHGUY App2 VRF2 BD4 10.10.40.1/24 EPG4
THETECHGUY App3 VRF3 BD5 10.10.50.1/24 EPG5
THETECHGUY App3 VRF3 BD6 10.10.60.1/24 EPG6

The BD3 doesn’t have the subnet, it’s correct. Great, after that I created the script…take a look:

from acitoolkit.acitoolkit import *
import credentials

session = Session(credentials.url, credentials.user, credentials.pwd)
session.login()

file = open(“data.txt”, “r”)
for line in file:
stripped_line = line.strip()
line_list = stripped_line.split()
single_string = line_list[0]
splitted_list = single_string.split(",")
tenant = Tenant(splitted_list[0])
app = AppProfile(splitted_list[1], tenant)
vrf = Context(splitted_list[2], tenant)
bd = BridgeDomain(splitted_list[3], tenant)
if splitted_list[4] == “":
print(”!!! NOTE: THIS BD DOESN’T HAVE A SUBNET !!!")
else:
bd_subnet = Subnet(splitted_list[5], bd)
bd_subnet.set_addr(splitted_list[4])
bd.add_subnet(bd_subnet)
bd.set_unknown_mac_unicast(‘flood’) #Enable ARP Flooding AND L2 Unknown Unicast
epg = EPG(splitted_list[5], app)
bd.add_context(vrf)
epg.add_bd(bd)
print(f"I’m going to push the following parameters\nTenant: {tenant}\nApplication Profile: {app}\nVRF: {vrf}\nBridge Domain: {bd}\nEPG: {epg}\n")
tenant.push_to_apic(session)
print(“Configuration applied successfully!\n\n\n”)
file.close()

I’ll not explain everything, I suggest you study Python and the most important libraries πŸ˜‰ Run it and see what happens:

six

Great, everything seems to be fine! Final check on the GUI:

seven

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Perfect!
You have successfully deployed a brand new Tenant with multiple Application Profiles, VRFs, BDs and EPGs. Moreover, you associate EPGs to BDs, BDs to VRFs and subnets to the relative BDs!

[❗ONE MORE THING…❗]
If you want to have more control of the operations, I created a script called “cfg_tenantFULL_interactive.py”, you can find it on GitHub
This script after each part asks “Are you sure you want to proceed?[y/n]":
nine

With this method, you can verify each parameter and decide if you are ok to push these parameters or not (just skip to the next one)

[❗/ONE MORE THING…❗]

Thanks for your time I hope that you’re enjoying my blog!
If you have some questions, please drop me a message through social networks!😊
πŸ‘ˆ You can find the relative icons here on the left of the page

Riccardo