This project demonstrates how I built an automated network configuration system for a simulated multi-router VyOS lab.
The goal was to move away from manual CLI work and adopt modern infrastructure-as-code practices:

• Configurations are templated in Jinja2.
• Device variables live in a structured inventory.
• Python scripts handle config generation, backups, diffs, and deployments.
• Logs and backups are automatically managed for traceability.
• CI/CD validates configs before anything touches the lab.

• Problem I solved: Manual configuration across multiple routers is error-prone and inconsistent.
• My approach: Automate the entire config lifecycle — generation, validation, deployment, and rollback.
• Technologies used:
  • Python (Netmiko, Jinja2, PyYAML, dotenv, Rich)
  • VyOS routers running in VirtualBox/GNS3
  • GitHub Actions for CI/CD checks
• Key features:
  • Generate configs from templates and inventory
  • Run diffs between intended vs. running configs
  • Backup current configs before deployment
  • Push only missing commands (idempotent)
  • Parallel deployments (async workers)
  • Post-deploy validation (OSPF neighbors, BGP sessions, default routes)
  • Centralized logging with rotation
  • Automatic cleanup of old logs/backups

network-automation-python/
├── README.md # Project documentation (this file)
├── .env.example # Example environment variables (copy to .env)
├── inventory/ # YAML inventory (device definitions, ASNs, IPs)
│ └── lab.yml
├── templates/ # Jinja2 templates (base, OSPF, BGP)
│ ├── base_vyos.j2
│ ├── ospf_vyos.j2
│ └── bgp_vyos.j2
├── configs/ # Static sample configs (if needed)
├── configs_generated/ # Auto-generated configs (gitignored)
├── backups/ # Device backups with timestamp (gitignored)
├── logs/ # Rotating logs + per-device validation output
├── scripts/ # Python automation scripts
│ ├── common.py
│ ├── deploy_async.py
│ ├── diff.py
│ ├── backup.py
│ ├── validate.py
│ ├── cleanup.py
│ └── logging_config.py
└── .github/workflows/ci.yml # CI/CD pipeline (lint + config build)

• Python 3.9+
• Virtual environment (python -m venv .venv)
• Dependencies from requirements.txt: pip install -r requirements.txt
• VyOS routers running in VirtualBox or GNS3
• SSH enabled on all routers (set service ssh port 22)
• Unique management IPs reachable from the automation host

1. Copy the example env file:

cp .env.example .env

2. Edit .env with your credentials (password or SSH key).
3. Verify inventory file (inventory/lab.yml) has correct IPs and ASNs.

The network automation process is divided into a clear, six-step workflow:

1. Generate Configs

   python scripts/deploy_async.py --generate-only

   This script generates .set configuration files in the configs_generated/ directory, pulling data from an inventory and applying it to predefined templates.

2. Compare Intended vs. Running Configs

   python scripts/diff.py

   This command shows a line-by-line comparison between the newly generated configurations and the configurations currently active on the network devices, allowing for a clear "what-if" analysis before deployment.

3. Take Backups

   python scripts/backup.py

   Before any changes are pushed, this script takes a backup of the current device configurations, saving them to the backups/ directory with a timestamp. This provides a critical safety net for easy rollback.

4. Deploy Changes (Parallel & Idempotent)

   python scripts/deploy_async.py --max-workers 6

   This is the core deployment script. It connects to each router and pushes only the missing commands, making the operation idempotent. It supports concurrent connections with a configurable number of workers for faster deployment across multiple devices.

5. Validate Post-Deploy

   python scripts/validate.py

   After deployment, this script verifies that the intended state has been achieved by checking for OSPF adjacencies, BGP sessions, and default routes.

6. Cleanup Old Logs/Backups

   python scripts/cleanup.py

   This script helps maintain a tidy repository by removing old log files and backups that are older than the retention period defined in the .env file.

This project is integrated with GitHub Actions to automate key tasks on every push or pull request:

• Lints Python code with flake8.
• Generates configs in a dry-run mode.
• Runs unit tests with pytest.
• Uploads configs_generated/ as build artifacts.

• Reduced manual CLI work by more than 80%, demonstrating the power of network automation.
• Practiced building idempotent, safe automation, similar to enterprise-grade tools like Ansible or Puppet.
• Integrated network automation with modern CI/CD pipelines.
• Designed for extensibility, allowing for easy future integration of features like BFD or NetBox.
• Combined network engineering fundamentals with Python development skills.

• Add commit-confirm rollback logic for VyOS devices.
• Extend templates to support ACLs, route-maps, and summarization.
• Replace Netmiko with scrapli or asyncssh for faster connections.
• Tie into a source-of-truth (e.g., NetBox) to manage inventory.

This project is licensed under the MIT License. Feel free to use it as a reference or template for your own projects. Attribution is appreciated.