Day15.md

Day 15: Configuration Management - Merging Configurations

Objective:

Learn how to apply partial configurations to the cEOS router using load_merge_candidate() and commit_config().

Concepts:

• load_merge_candidate(): Merges a new configuration with the existing running configuration.
• commit_config(): Applies the candidate configuration to the running configuration.
• compare_config(): Shows the difference between the running and candidate configurations.
• discard_config(): Discards the candidate configuration.

Challenge:

Add a loopback interface and a static route to arista1 using load_merge_candidate().

Code Examples:

1. day3_merge_config.py:

from napalm import get_network_driver
import json

DEVICE_IP = "YOUR_ARISTA1_IP"
USERNAME = "admin"
PASSWORD = "admin"

driver = get_network_driver("eos")
device = driver(
    hostname=DEVICE_IP,
    username=USERNAME,
    password=PASSWORD,
    optional_args={"secret": PASSWORD}
)

# Configuration to merge
new_config = """
interface Loopback1
    description "Managed by NAPALM"
    ip address 10.0.0.1/32
ip route 192.168.10.0/24 Null0 10
"""

try:
    device.open()
    print("Loading merge candidate configuration...")
    device.load_merge_candidate(config=new_config)

    print("\n--- Configuration Difference ---")
    diff = device.compare_config()
    print(diff)

    if diff:
        print("\nCommitting configuration...")
        device.commit_config()
        print("Configuration committed successfully.")
    else:
        print("No changes detected, discarding candidate.")
        device.discard_config()

except Exception as e:
    print(f"Error: {e}")
    # Important: Discard candidate config in case of error
    if device.is_opened:
        device.discard_config()
        print("Discarding candidate configuration due to error.")
finally:
    if device.is_alive():
        device.close()