Empowering Network Automation

Welcome to DEVWKS-2551 Empowering Network Automation, Practice NSO with Python

This file provides the instructions you'll need for the workshop. However, don't feel restricted to the workshop timeline. Feel free to explore and try out the exercises at your own pace. Simply click on the Cisco Cloud IDE Run it! button located at the top left corner to get started at any time.

For your convenience, all the information shared during the workshop is compiled in the NSO Python API markdown file. Consider it your go-to resource for reference.

Objective

Start on a hands-on journey to learn the NSO Python API. We've designed this workshop around the concept of learning by fixing. You'll dive into broken examples, unravel the issues, and learn how to navigate the Python API in the process.

This approach not only gives you practical experience but also equips you with the problem-solving skills needed in real-world programming. Get ready to transform challenges into learning opportunities.

Setup the environment

Setup the environment required for the lab.

cd ~/src/DEVWKS-2551/

make

Note

If you receive an error during the setup, enter make again. If there are too many issues, reset the environment.

If you're curious to see the working examples, feel free to explore the files in the the answer directory. Alternatively, if you're ready to test your skills, you can replace the problematic files with the correct ones and see if they work as expected.

Scenario 1. Scripting with the NSO Python API

Our first scenario offers a straightforward example of how to change a device's hostname using the Python NSO API, providing a hands-on opportunity to familiarize yourself with its interaction.

To identify the problem, you can either debug the code or utilize the helper functions embedded in the script, designed to simplify error detection.

Start by running the ncs_scripting.py file.

python ~/src/DEVWKS-2551/scripting/ncs_scripting.py

You can also get the same data via RESTCONF

python ~/src/DEVWKS-2551/scripting/restconf_scripting.py

Scenario 2. Run services with NSO Python API

This example showcases an NSO service that use Python to simplify templates, making them easier to maintain.

Note

Work with the files under the packages/router directory. This package has a symbolic link to the running NSO packages directory.

Prepare the example

First compile the package used.

make clean all -C ${NCS_RUN_DIR}/packages/router/src/

Reload the packages.

echo "packages reload" | ncs_cli -C -u admin

Test the example

Test if the package works correctly.

ncs_cli -Cu admin

config

Pick any one or multiple lines below to test the router package.

router core device core-rtr0 sys dns server 1.1.1.1
router core device core-rtr0 sys syslog server 1.1.1.1
router core device core-rtr0 sys syslog server 2.2.2.2
router core device core-rtr0 sys ntp server 1.1.1.1
router core device core-rtr0 sys ntp server 2.2.2.2
router distribution device dist-rtr0 sys dns server 6.6.6.6
router distribution device dist-rtr0 sys dns server 5.5.5.5
router distribution device dist-rtr0 sys syslog server 6.6.6.6
router access device dist-sw0 sys dns server 4.4.4.4
router access device dist-sw0 sys dns server 3.3.3.3
router access device dist-sw0 sys syslog server 4.4.4.4
router access device dist-sw0 sys syslog server 3.3.3.3
router access device dist-sw0 sys ntp server 4.4.4.4
router access device dist-sw0 sys ntp server 3.3.3.3

Do a dry-run to make sure the package is working correctly.

commit dry-run

Note

If issues, review the router python script under the packages directoy.

Redeploy the package if you make changes to the python script.

packages package router redeploy

Test the package again with a commit dry-run

Finally, when the package is fixed, commit the changes.

commit

Scenario 3. Interact with NSO programmatically

Interact with NSO adding a new DNS server using the RESTCONF interface, which is useful when integrating NSO with external systems.

Use the restconf_service.py file. On this example the http code is already correctly implemented.

python ~/src/DEVWKS-2551/scripting/restconf_service.py

Bonus. Development

This exercise was developed using the official NSO container. The compose file used for development is kept for reference and is not part of the workshop.

However the build_workshop script only copies the router package correctly in the NSO Playground. If you are working with the container locally, you need to copy the router package manually.

Useful commands

Access netsim cli device.

ncs-netsim cli-c core-rtr0 --dir ~/src/workshop/netsim
show running-config hostname

Use show commands using live-status on NSO.

devices device core-rtr0 live-status exec show running-config hostname

Redeploy the router packages for changes on python code or templates files.

echo 'packages package router redeploy' | ncs_cli -Cu admin