An Overview of Junos Rescue and Recovery Options

When studying for the JNCIS-ENT certification, it's crucial to understand the various rescue and recovery options available in Junos. These options can be lifesavers when you're dealing with system failures or configuration issues. In this post, we'll delve into the different rescue and recovery options, including the rescue configuration, snapshot, and rollback features.

Rescue Configuration

The rescue configuration is a known good configuration that you can revert to if you encounter issues with the current active configuration. This configuration is stored in a protected area of the file system and is not affected by system reboots or upgrades.

To save a rescue configuration, use the request system configuration rescue save command. This command saves the current active configuration as the rescue configuration.

user@host> request system configuration rescue save

To revert to the rescue configuration, use the rollback rescue command in configuration mode, and then commit the changes.

user@host# rollback rescue
user@host# commit

Snapshot

A snapshot is a copy of the entire file system, including the Junos OS software and all configurations. You can use a snapshot to recover the system in case of a software failure.

To create a snapshot, use the request system snapshot command. This command creates a snapshot and stores it in the alternate root partition.

user@host> request system snapshot

To recover the system using a snapshot, use the request system reboot media internal command. This command reboots the system from the alternate root partition, which contains the snapshot.

user@host> request system reboot media internal

Rollback

Junos OS automatically saves the last 50 configurations. You can rollback to any of these configurations using the rollback command in configuration mode.

To display the list of saved configurations, use the show system commit command.

user@host> show system commit

To rollback to a specific configuration, use the rollback command followed by the configuration number.

user@host# rollback 1
user@host# commit

In conclusion, Junos provides several rescue and recovery options that can help you recover from system failures or configuration issues. Understanding these options is not only crucial for real-world network engineering but also for passing the JNCIS-ENT certification exam. So, make sure to practice these commands and understand how they work.