NAPALM with Python: The Multivendor support for Network Automation

Introduction

Welcome to Part 6 of our Python for Network Automation series. Today, we're diving deep into NAPALM, a Python library that's revolutionizing network automation.

Dive In:

1. Understanding NAPALM

NAPALM (Network Automation and Programmability Abstraction Layer with Multivendor support) - is a Python library designed to simplify the process of automating network devices. It abstracts the underlying device interactions, making it easier to work with devices from different vendors.
Supported platforms include:

- Cisco IOS
- Juniper Junos
- Nokia SRoS
- Nokia SRL
- Arista EOS
- Cisco NX-OS
- Cisco IOS-XR
- And many more...

For network engineers, NAPALM is a versatile tool that streamlines tasks, making automation more accessible and efficient.
This means that instead of writing separate scripts or functions for each type of device, you can write one script that works across all of them.

Why Use NAPALM?

1. Vendor Agnostic: With NAPALM, you don't need to get bogged down with the specifics of each vendor's command-line interface (CLI) or API. NAPALM provides a unified approach.
2. Consistency: NAPALM ensures that the output you receive, regardless of the underlying device, is consistent and in a structured format, typically JSON. This makes parsing and further automation tasks much more straightforward.
3. Extensibility: As an open-source tool, NAPALM is continuously evolving. The community regularly contributes to its growth, adding support for more devices and features.
4. Integration: NAPALM can be seamlessly integrated with other automation tools and frameworks, such as Ansible, SaltStack, and more.

2. Setting Up NAPALM

Before diving into automation, you need to set up NAPALM. It's as simple as using pip:
```python
pip install napalm


Once installed, you're ready to start automating your network tasks.

3. Organizing Your Devices

For efficient automation, maintaining a structured inventory of your devices is crucial. This inventory can be in the form of a YAML or JSON file. Here's a sample YAML structure:


With this inventory, you can easily access and manage device information, making automation tasks smoother.

4. Making Connections with NAPALM

NAPALM provides various drivers to connect to different network devices. Here's how you can establish a connection:

This code establishes a connection to the devices, allowing you to execute further automation tasks.

5. Gathering Device Information

NAPALM can fetch a plethora of information about a device, such as its hostname, serial number, interfaces, and more. Here's how:

The `get_facts()` method returns a dictionary containing various details about the device. This can be invaluable for monitoring and automation.

6. Efficient Configuration Management

One of NAPALM's strengths is its ability to manage device configurations. You can load, compare, and commit configurations seamlessly. Here's a brief overview:

After staging, you can commit the changes to make them part of the running configuration.

This ensures that your configurations are applied correctly and efficiently.

7. The Importance of Backups

Regularly backing up configurations is vital for disaster recovery and auditing. NAPALM makes this process straightforward:


This ensures that you always have a recent backup of your configurations, safeguarding against potential issues.

8. Monitoring Your Network's Health

NAPALM provides tools to check the health of your network, such as BGP status, interface status, and ARP tables.


This helps in proactive monitoring and quick troubleshooting.

9. Ensuring Configuration Compliance

Ensuring configurations adhere to predefined standards is crucial. NAPALM can validate configurations against templates:

This ensures your network adheres to best practices and standards.

Real-Time Use Cases with Examples:

Bulk Configuration Changes:
Scenario: Imagine you need to change the SNMP community string across all devices in your network for security reasons.
With NAPALM: Instead of logging into each device and making changes manually or using vendor-specific scripts, you can use NAPALM to push the changes across all devices, irrespective of the vendor.

Network Audit:
Scenario: You want to ensure that all devices in your network have the correct NTP servers configured.
With NAPALM: Fetch the NTP configuration from all devices and compare it against the standard.

Zero-Touch Provisioning:
Scenario: You have a new switch, and you want to configure it without any manual intervention.
With NAPALM: Use NAPALM to push the base configuration to the new switch as soon as it's connected to the network.

Network Health Checks:
Scenario: You want a daily report of any interfaces that are down.
With NAPALM: Fetch interface status daily and report any anomalies.

11. Best Practices for NAPALM:

When using NAPALM, consider the following best practices:
1. Error Handling: Implement robust error handling to manage exceptions.
2. Testing: Test scripts in a controlled environment before production.
3. Documentation: Maintain clear documentation for future reference.
4. Version Control: Use systems like Git to track script changes.

Conclusion:

Through our exploration of NAPALM with Python, we've seen its transformative power in streamlining multi-vendor network operations. From efficient configuration management to real-world application scenarios, NAPALM emerges as an essential tool for modern network engineers. 
As we wrap up, remember: in the realm of network automation, tools like NAPALM are not just advantageous—they're indispensable. Dive in, keep learning, and above all,
Happy Automating!