Configuration Rollback; Configuration Rollback Confirmed Change; Benefits Of Configuration Replace And Configuration Rollback - Cisco Catalyst 9400 System Management Configuration Manual

Configuration Rollback

Configuration Rollback
The concept of rollback comes from the transactional processing model common to database operations. In
a database transaction, you might make a set of changes to a given database table. You then must choose
whether to commit the changes (apply the changes permanently) or to roll back the changes (discard the
changes and revert to the previous state of the table). In this context, rollback means that a journal file containing
a log of the changes is discarded, and no changes are applied. The result of the rollback operation is to revert
to the previous state, before any changes were applied.
The configure replace command allows you to revert to a previous configuration state, effectively rolling
back changes that were made since the previous configuration state was saved. Instead of basing the rollback
operation on a specific set of changes that were applied, the Cisco IOS configuration rollback capability uses
the concept of reverting to a specific configuration state based on a saved Cisco IOS configuration file. This
concept is similar to the database idea of saving a checkpoint (a saved version of the database) to preserve a
specific state.
If the configuration rollback capability is desired, you must save the Cisco IOS running configuration before
making any configuration changes. Then, after entering configuration changes, you can use that saved
configuration file to roll back the changes (using the configure replace target-url command). Furthermore,
because you can specify any saved Cisco IOS configuration file as the replacement configuration, you are not
limited to a fixed number of rollbacks, as is the case in some rollback models.

Configuration Rollback Confirmed Change

The Configuration Rollback Confirmed Change feature allows configuration changes to be performed with
an optional requirement that they be confirmed. If this confirmation is not received, the configuration is
returned to the state prior to the changes being applied. The mechanism provides a safeguard against inadvertent
loss of connectivity between a network device and the user or management application due to configuration
changes.

Benefits of Configuration Replace and Configuration Rollback

• Allows you to revert to a previous configuration state, effectively rolling back configuration changes.
• Allows you to replace the current running configuration file with the startup configuration file without
• Allows you to revert to any saved Cisco IOS configuration state.
• Simplifies configuration changes by allowing you to apply a complete configuration file to the device,
• When using the configure replace command as an alternative to the copy source-url running-config
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having to reload the device or manually undo CLI changes to the running configuration file, therefore
reducing system downtime.
where only the commands that need to be added or removed are affected.
command, increases efficiency and prevents risk of service outages by not reapplying existing commands
in the current running configuration.
Configuration Replace and Configuration Rollback