Working with Configuration Files

This chapter describes how to work with your device configuration files.

Information About Configuration Files

Configuration files contain the Cisco NX-OS software commands used to configure the features on a Cisco NX-OS device. Commands are parsed (translated and executed) by the Cisco NX-OS software when the system is booted (from the startup-config file) or when you enter commands at the CLI in a configuration mode.

To change the startup configuration file, you can either save the running-configuration file to the startup configuration using the copy running-config startup-config command or copy a configuration file from a file server to the startup configuration.

Types of Configuration Files

The Cisco NX-OS software has two types of configuration files, running configuration and startup configuration. The device uses the startup configuration (startup-config) during device startup to configure the software features. The running configuration (running-config) contains the current changes that you make to the startup-configuration file. The two configuration files can be different. You might want to change the device configuration for a short time period rather than permanently. In this case, you would change the running configuration by using commands in global configuration mode but not save the changes to the startup configuration.

To change the running configuration, use the configure terminal command to enter global configuration mode. As you use the Cisco NX-OS configuration modes, commands generally are executed immediately and are saved to the running configuration file either immediately after you enter them or when you exit a configuration mode.

To change the startup-configuration file, you can either save the running configuration file to the startup configuration or download a configuration file from a file server to the startup configuration.

Managing Configuration Files

This section describes how to manage configuration files.

Saving the Running Configuration to the Startup Configuration

You can save the running configuration to the startup configuration to save your changes for the next time you that reload the device.

SUMMARY STEPS

  1. (Optional) show running-config
  2. copy running-config startup-config

DETAILED STEPS

  Command or Action Purpose
Step 1

(Optional) show running-config

Example:

switch# show running-config
 (Optional)

Displays the running configuration.
Step 2

copy running-config startup-config

Example:

switch# copy running-config startup-config

Copies the running configuration to the startup configuration.

Copying a Configuration File to a Remote Server

You can copy a configuration file stored in the internal memory to a remote server as a backup or to use for configuring other Cisco NX-OS devices.

SUMMARY STEPS

  1. copy running-config scheme:// server/ [url / ]filename
  2. copy startup-config scheme:// server/ [url / ]filename

DETAILED STEPS

  Command or Action Purpose
Step 1

copy running-config scheme:// server/ [url / ]filename

Example:

switch# copy running-config 
tftp://10.10.1.1/sw1-run-config.bak

Copies the running-configuration file to a remote server.

For the scheme argument, you can enter tftp: , ftp: , scp: , or sftp: . The server argument is the address or name of the remote server, and the url argument is the path to the source file on the remote server.

The server, url, and filename arguments are case sensitive.

Step 2

copy startup-config scheme:// server/ [url / ]filename

Example:

switch# copy startup-config 
tftp://10.10.1.1/sw1-start-config.bak

Copies the startup-configuration file to a remote server.

For the scheme argument, you can enter tftp: , ftp: , scp: , or sftp: . The server argument is the address or name of the remote server, and the url argument is the path to the source file on the remote server.

The server, url, and filename arguments are case sensitive.

Example

Downloading the Running Configuration From a Remote Server

You can configure your Cisco NX-OS device by using configuration files that you created on another Cisco NX-OS device and uploaded to a remote server. You then download the file from the remote server to your device using TFTP, FTP, Secure Copy (SCP), or Secure Shell FTP (SFTP) to the running configuration.

Before you begin

Ensure that the configuration file that you want to download is in the correct directory on the remote server.

Ensure that the permissions on the file are set correctly. Permissions on the file should be set to world-read.

Ensure that your Cisco NX-OS device has a route to the remote server. The Cisco NX-OS device and the remote server must be in the same subnetwork if you do not have a router or a default gateway to route traffic between subnets.

Check connectivity to the remote server using the ping or ping6 command.

SUMMARY STEPS

  1. copy scheme:// server/ [url/ ]filename running-config
  2. (Optional) show running-config
  3. (Optional) copy running-config startup-config
  4. (Optional) show startup-config

DETAILED STEPS

  Command or Action Purpose
Step 1

copy scheme:// server/ [url/ ]filename running-config

Example:

switch# copy tftp://10.10.1.1/my-config 
running-config

Downloads the running-configuration file from a remote server.

For the scheme argument, you can enter tftp: , ftp: , scp: , or sftp: . The server argument is the address or name of the remote server, and the url argument is the path to the source file on the remote server.

The server, url, and filename arguments are case sensitive.

Step 2

(Optional) show running-config

Example:

switch# show running-config
 (Optional)

Displays the running configuration.
Step 3

(Optional) copy running-config startup-config

Example:

switch# copy running-config startup-config
 (Optional)

Copies the running configuration to the startup configuration.

Step 4

(Optional) show startup-config

Example:

switch# show startup-config
 (Optional)

Displays the startup configuration.

Downloading the Startup Configuration From a Remote Server

You can configure your Cisco NX-OS device by using configuration files that you created on another Cisco NX-OS device and uploaded to a remote server. You then download the file from the remote server to your device using TFTP, FTP, Secure Copy (SCP), or Secure Shell FTP (SFTP) to the startup configuration.


Caution

This procedure disrupts all traffic on the Cisco NX-OS device.

Before you begin

Log in to a session on the console port.

Ensure that the configuration file that you want to download is in the correct directory on the remote server.

Ensure that the permissions on the file are set correctly. Permissions on the file should be set to world-read.

Ensure that your Cisco NX-OS device has a route to the remote server. The Cisco NX-OS device and the remote server must be in the same subnetwork if you do not have a router or a default gateway to route traffic between subnets.

Check connectivity to the remote server using the ping or ping6 command.

SUMMARY STEPS

  1. write erase
  2. reload
  3. copy scheme:// server/ [url / ]filename running-config
  4. copy running-config startup-config
  5. (Optional) show startup-config

DETAILED STEPS

  Command or Action Purpose
Step 1

write erase

Example:

switch# write erase

Erases the startup configuration file.

Step 2

reload

Example:

switch# reload
This command will reboot the system. (y/n)?  [n] y
...
Enter the password for "admin": <password>
Confirm the password for "admin": <password>
...
Would you like to enter the basic configuration 
dialog (yes/no): n
switch#

Reloads the Cisco NX-OS device.

Note 

Do not use the setup utility to configure the device.

Step 3

copy scheme:// server/ [url / ]filename running-config

Example:

switch# copy tftp://10.10.1.1/my-config 
running-config

Downloads the running configuration file from a remote server.

For the scheme argument, you can enter tftp: , ftp: , scp: , or sftp: . The server argument is the address or name of the remote server, and the url argument is the path to the source file on the remote server.

The server, url, and filename arguments are case sensitive.

Step 4

copy running-config startup-config

Example:

switch# copy running-config 
startup-config

Saves the running configuration file to the startup configuration file.

Step 5

(Optional) show startup-config

Example:

switch# show startup-config
 (Optional)

Displays the running configuration.

Copying Configuration Files to an External Flash Memory Device

You can copy configuration files to an external flash memory device as a backup for later use.

Before you begin

Insert the external Flash memory device into the active supervisor module.

SUMMARY STEPS

  1. (Optional) dir {slot0: | usb1: | usb2: }[directory/ ]
  2. copy running-config {slot0: | usb1: | usb2: }[directory/ ]filename
  3. copy startup-config {slot0: | usb1: | usb2: }[directory/ ]filename

DETAILED STEPS

  Command or Action Purpose
Step 1

(Optional) dir {slot0: | usb1: | usb2: }[directory/ ]

Example:

switch# dir slot0:
 (Optional)

Displays the files on the external flash memory device.

Step 2

copy running-config {slot0: | usb1: | usb2: }[directory/ ]filename

Example:

switch# copy running-config slot0:dsn-running-config.cfg

Copies the running configuration to an external flash memory device. The filename argument is case sensitive.

Step 3

copy startup-config {slot0: | usb1: | usb2: }[directory/ ]filename

Example:

switch# copy startup-config slot0:dsn-startup-config.cfg

Copies the startup configuration to an external flash memory device. The filename argument is case sensitive.

Copying the Running Configuration from an External Flash Memory Device

You can configure your Cisco NX-OS device by copying configuration files created on another Cisco NX-OS device and saved to an external flash memory device.

Before you begin

Insert the external flash memory device into the active supervisor module.

SUMMARY STEPS

  1. (Optional) dir {slot0: | usb1: | usb2: }[directory/ ]
  2. copy {slot0: | usb1: | usb2: }[directory/ ]filename running-config
  3. (Optional) show running-config
  4. (Optional) copy running-config startup-config
  5. (Optional) show startup-config

DETAILED STEPS

  Command or Action Purpose
Step 1

(Optional) dir {slot0: | usb1: | usb2: }[directory/ ]

Example:

switch# dir slot0:
 (Optional)

Displays the files on the external flash memory device.

Step 2

copy {slot0: | usb1: | usb2: }[directory/ ]filename running-config

Example:

switch# copy slot0:dsn-config.cfg running-config

Copies the running configuration from an external flash memory device. The filename argument is case sensitive.

Step 3

(Optional) show running-config

Example:

switch# show running-config
 (Optional)

Displays the running configuration.

Step 4

(Optional) copy running-config startup-config

Example:

switch# copy running-config startup-config
 (Optional)

Copies the running configuration to the startup configuration.

Step 5

(Optional) show startup-config

Example:

switch# show startup-config
 (Optional)

Displays the startup configuration.

Copying the Startup Configuration from an External Flash Memory Device

You can recover the startup configuration on your Cisco NX-OS device by downloading a new startup configuration file saved on an external flash memory device.

Before you begin

Insert the external flash memory device into the active supervisor module.

SUMMARY STEPS

  1. (Optional) dir {slot0: | usb1: | usb2: }[directory/ ]
  2. copy {slot0: | usb1: | usb2: }[directory / ]filename startup-config
  3. (Optional) show startup-config

DETAILED STEPS

  Command or Action Purpose
Step 1

(Optional) dir {slot0: | usb1: | usb2: }[directory/ ]

Example:

switch# dir slot0:
 (Optional)

Displays the files on the external flash memory device.

Step 2

copy {slot0: | usb1: | usb2: }[directory / ]filename startup-config

Example:

switch# copy slot0:dsn-config.cfg startup-config

Copies the startup configuration from an external flash memory device. The filename argument is case sensitive.

Step 3

(Optional) show startup-config

Example:

switch# show startup-config
 (Optional)

Displays the startup configuration.

Copying Configuration Files to an Internal File System

You can copy configuration files to the internal memory as a backup for later use.

SUMMARY STEPS

  1. copy running-config [filesystem: ][directory/ ] | [directory/ ]filename
  2. copy startup-config [filesystem: ][directory/ ] | [directory/ ]filename

DETAILED STEPS

  Command or Action Purpose
Step 1

copy running-config [filesystem: ][directory/ ] | [directory/ ]filename

Example:

switch# copy running-config bootflash:sw1-run-config.bak

Copies the running-configuration file to internal memory.

The filesystem , directory , and filename arguments are case sensitive.

Step 2

copy startup-config [filesystem: ][directory/ ] | [directory/ ]filename

Example:

switch# copy startup-config bootflash:sw1-start-config.bak

Copies the startup-configuration file to internal memory.

The filesystem , directory , and filename arguments are case sensitive.

Rolling Back to a Previous Configuration

Problems, such as memory corruption, can occur that make it necessary for you to recover your configuration from a backed up version.


Note

Each time that you enter a copy running-config startup-config command, a binary file is created and the ASCII file is updated. A valid binary configuration file reduces the overall boot time significantly. A binary file cannot be uploaded, but its contents can be used to overwrite the existing startup configuration. The write erase command clears the binary file.

SUMMARY STEPS

  1. write erase
  2. reload
  3. copy configuration_file running-configuration
  4. copy running-config startup-config

DETAILED STEPS

  Command or Action Purpose
Step 1

write erase

Example:

switch# write erase

Clears the current configuration of the switch.

Step 2

reload

Example:

switch# reload

Restarts the device. You will be prompted to provide a kickstart and system image file for the device to boot and run.

Note 

By default, the reload command reloads the device from a binary version of the startup configuration.

Beginning with Cisco NX-OS 6.2(2), you can use the reload ascii command to copy an ASCII version of the configuration to the start up configuration when reloading the device.

Step 3

copy configuration_file running-configuration

Example:

switch# copy bootflash:start-config.bak running-configuration

Copies a previously saved configuration file to the running configuration.

Note 

The configuration_file filename argument is case sensitive.

Step 4

copy running-config startup-config

Example:

switch# copy running-config startup-config

Copies the running configuration to the start-up configuration.

Removing the Configuration for a Missing Module

When you remove an I/O module from the chassis, you can also remove the configuration for that module from the running configuration.


Note

You can only remove the configuration for an empty slot in the chassis.

Before you begin

Remove the I/O module from the chassis.

SUMMARY STEPS

  1. (Optional) show hardware
  2. purge module slot running-config
  3. (Optional) copy running-config startup-config

DETAILED STEPS

  Command or Action Purpose
Step 1

(Optional) show hardware

Example:

switch# show hardware
 (Optional)

Displays the installed hardware for the device.
Step 2

purge module slot running-config

Example:

switch# purge module 3 running-config

Removes the configuration for a missing module from the running configuration.
Step 3

(Optional) copy running-config startup-config

Example:

switch# copy running-config startup-config
 (Optional)

Copies the running configuration to the startup configuration.

Erasing a Configuration

You can erase the configuration on your device to return to the factory defaults.

You can erase the following configuration files saved in the persistent memory on the device:

  • Startup

  • Boot

  • Debug

The write erase command erases the entire startup configuration, except for the following:

  • Boot variable definitions
  • The IPv4 configuration on the mgmt0 interface, including the following:
    • Address
    • Subnet mask

To remove the boot variable definitions follow step-1 and step-2.

To remove the boot variables, running configuration, and the IP configuration on the management interface follow step-3 to step-5.

SUMMARY STEPS

  1. write erase boot
  2. reload
  3. write erase
  4. write erase boot
  5. reload

DETAILED STEPS

  Command or Action Purpose
Step 1

write erase boot

Example:


switch# write erase boot

Erases the boot variable definitions.

Step 2

reload

Example:


switch# reload

Restarts the device. You will be prompted to provide a kickstart and system image file for the device to boot and run. By default, the reload command reloads the device from a binary version of the startup configuration.

Step 3

write erase

Example:


switch# write erase

Erases the boot variable definitions.

Step 4

write erase boot

Example:


switch# write erase boot

Erases the boot variable definitions and the IPv4 configuration on the management interface.

Step 5

reload

Example:


switch# reload

Restarts the device. You will be prompted to provide a kickstart and system image file for the device to boot and run. By default, the reload command reloads the device from a binary version of the startup configuration.

Verifying the Device Configuration

To verify the configuration after bootstrapping the device using POAP, use one of the following commands:

Command

Purpose

show running-config

Displays the running configuration.

show startup-config

Displays the startup configuration.

For detailed information about the fields in the output from these commands, see the Cisco Nexus command reference for your device.

Examples of Working with Configuration Files

This section includes examples of working with configuration files.

Copying Configuration Files

This example shows how to overwrite the contents of an existing configuration in NVRAM:

switch# copy nvram:snapshot-config nvram:startup-config
Warning: this command is going to overwrite your current startup-config.
Do you wish to continue? {y/n} [y] y

This example shows how to copy a running configuration to the bootflash: file system:

switch# copy system:running-config bootflash:my-config

Backing Up Configuration Files

This example shows how to create a snapshot of the startup configuration in a predefined location on the device (binary file):

switch# copy startup-config nvram:snapshot-config

This example shows how to back up the startup configuration to the bootflash: file system (ASCII file):

switch# copy startup-config bootflash:my-config

This example shows how to back up the startup configuration to the TFTP server (ASCII file):

switch# copy startup-config tftp://172.16.10.100/my-config

This example shows how to back up the running configuration to the bootflash: file system (ASCII file):

switch# copy running-config bootflash:my-config

Rolling Back to a Previous Configuration

To roll back your configuration to a snapshot copy of a previously saved configuration, you need to perform the following steps:

  1. Clear the current running image with the write erase command.

  2. Restart the device with the reload command.


    Note

    By default, the reload command reloads the device from a binary version of the startup configuration.

    Beginning with Cisco NX-OS 6.2(2), you can use the reload ascii command to copy an ASCII version of the configuration to the start up configuration when reloading the device.

  3. Copy the previously saved configuration file to the running configuration with the copy configuration_file running-configuration command.

  4. Copy the running configuration to the start-up configuration with the copy running-config startup-config command.