How to Save Running Config Cisco: A Symphony of Commands and Coffee Stains

Saving the running configuration on a Cisco device is a fundamental task for network administrators, yet it often feels like a ritual that blends technical precision with a touch of personal flair. Whether you’re a seasoned network engineer or a novice just dipping your toes into the world of Cisco IOS, understanding the nuances of this process can save you from potential disasters and sleepless nights. In this article, we’ll explore the various methods to save your running configuration, discuss why it’s crucial, and even delve into some philosophical musings about the nature of network configurations.

The Basics: Why Save the Running Config?

Before diving into the “how,” it’s essential to understand the “why.” The running configuration is the current configuration of your Cisco device, stored in RAM. This configuration is volatile, meaning it will be lost if the device is rebooted or loses power. To preserve your hard work and ensure that your network settings persist across reboots, you need to save the running configuration to the startup configuration, which is stored in non-volatile memory (NVRAM).

Method 1: The Classic write memory Command

The most straightforward way to save your running configuration is by using the write memory command. This command copies the running configuration to the startup configuration, ensuring that your settings are preserved.

Router# write memory

This command is a relic from the early days of Cisco IOS, and while it’s still functional, it’s often considered a bit old-school. However, it gets the job done, and sometimes, simplicity is key.

Method 2: The Modern copy running-config startup-config Command

For those who prefer a more modern approach, the copy running-config startup-config command is the way to go. This command is more verbose but also more descriptive, making it easier for newcomers to understand what’s happening.

Router# copy running-config startup-config

This command essentially does the same thing as write memory but is more aligned with the current Cisco IOS syntax. It’s a matter of personal preference, but using this command can make your scripts and documentation more consistent with modern practices.

Method 3: The GUI Approach

For those who prefer a graphical interface, Cisco devices often come with a web-based management tool called Cisco Configuration Professional (CCP) or the more modern Cisco DNA Center. These tools allow you to save the running configuration with just a few clicks, making the process more accessible for those who are less comfortable with the command line.

While the GUI approach is user-friendly, it’s worth noting that it may not be as fast or efficient as using the command line, especially when managing multiple devices or performing bulk operations.

Advanced Techniques: Automation and Scripting

In larger networks, manually saving the running configuration on each device can be time-consuming and error-prone. This is where automation comes into play. Tools like Ansible, Python scripts, or even Cisco’s own Embedded Event Manager (EEM) can be used to automate the process of saving configurations.

Using Ansible

Ansible is a powerful automation tool that can be used to manage Cisco devices. By writing a simple playbook, you can automate the process of saving the running configuration across multiple devices.

- name: Save running configuration on Cisco devices
  hosts: cisco_devices
  tasks:
    - name: Save running config
      ios_command:
        commands:
          - copy running-config startup-config

Using Python

For those who prefer scripting, Python combined with libraries like Netmiko can be a powerful tool. Here’s a simple script that logs into a Cisco device and saves the running configuration:

from netmiko import ConnectHandler

device = {
    'device_type': 'cisco_ios',
    'host': '192.168.1.1',
    'username': 'admin',
    'password': 'password',
}

connection = ConnectHandler(**device)
connection.send_command('copy running-config startup-config')
connection.disconnect()

Using EEM

Cisco’s Embedded Event Manager (EEM) allows you to create scripts that run directly on the device. You can create an EEM script that automatically saves the running configuration whenever a specific event occurs, such as a configuration change.

event manager applet SaveConfig
 event syslog pattern ".*%SYS-5-CONFIG_I.*"
 action 1.0 cli command "enable"
 action 2.0 cli command "copy running-config startup-config"

Philosophical Musings: The Nature of Network Configurations

Saving the running configuration is more than just a technical task; it’s a metaphor for the transient nature of life. Just as the running configuration exists only in the volatile memory of a device, our actions and decisions are fleeting, existing only in the moment. By saving the configuration, we preserve a snapshot of our work, much like how we capture memories to preserve our experiences.

In the grand scheme of things, the act of saving a configuration is a small but significant step in maintaining the stability and reliability of a network. It’s a reminder that even in the fast-paced world of technology, taking a moment to ensure that our work is preserved can make all the difference.

Related Q&A

Q: What happens if I don’t save the running configuration?

A: If you don’t save the running configuration, any changes you’ve made will be lost when the device is rebooted or loses power. This could lead to network downtime or misconfigurations that are difficult to troubleshoot.

Q: Can I save the running configuration to a remote server?

A: Yes, you can use the copy running-config tftp: or copy running-config ftp: commands to save the running configuration to a remote TFTP or FTP server. This is useful for backup purposes.

Q: Is there a way to automatically save the running configuration?

A: Yes, you can use automation tools like Ansible, Python scripts, or Cisco’s EEM to automate the process of saving the running configuration.

Q: What’s the difference between write memory and copy running-config startup-config?

A: Both commands achieve the same result—saving the running configuration to the startup configuration. The difference is mainly in syntax and personal preference. write memory is an older command, while copy running-config startup-config is more modern and descriptive.

Q: Can I save the running configuration on a switch?

A: Yes, the process of saving the running configuration is the same for both routers and switches. The commands and methods discussed in this article apply to both types of devices.