- play_arrow Junos OS Overview
- play_arrow Junos OS Overview
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- play_arrow System Backup and Recovery
- play_arrow Back Up an Installation
- play_arrow Recover Junos OS
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- play_arrow Installation, Upgrade, and Downgrade VM Host Software, and Back Up and Recovery of VM Host Devices
- play_arrow VM Host Overview and CLI Commands
- play_arrow Boot Process for Routers with VM Host Support
- play_arrow Installing, Upgrading, Backing Up, and Recovery of VM Host
- play_arrow Copying VM Host Installation Package to the PXE Boot Server
- play_arrow Upgrading NFX Devices
- play_arrow Creating an Emergency Boot Device for Routing Engines with VM Host Support
- play_arrow Upgrading Firmware on Routing Engines with VM Host Support
- play_arrow Disabling Autorecovery on Routing Engines with VM Host Support
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- play_arrow Installing and Upgrading the BIOS and Firmware
- play_arrow For Routers
- play_arrow For Switches
- play_arrow For Firewalls
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- play_arrow Zero Touch Provisioning and Secure Zero Touch Provisioning
- play_arrow Phone-Home Client
- play_arrow Automatic Installation of Configuration Files
- play_arrow Automatic Installation of Configuration Files
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- play_arrow Configuration Statements and Operational Commands
- play_arrow Configuration Statements and Operational Commands
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Managing YANG Packages and Configurations During a Software Upgrade or Downgrade
Certain devices running Junos OS enable you to load custom YANG modules on the device to add data models that are not natively supported by Junos OS. When you add, update, or delete a YANG data model, Junos OS rebuilds its schema and then validates the active configuration against the updated schema.
When you upgrade or downgrade Junos OS, by default, the system validates the software package or bundle against the current configuration. During the installation, the schema for custom YANG data models is not available. As a result, if the active configuration contains dependencies on these models, the software validation fails, which causes the upgrade or downgrade to fail.
In addition, devices that are running Junos OS based on FreeBSD version 6 remove custom YANG packages from the device during the software installation process. For this Junos OS variant, if the active configuration contains dependencies on custom YANG data models, the software installation fails even if you do not validate the software against the configuration, because the configuration data cannot be validated during the initial boot-time commit.
For these reasons, before you upgrade or downgrade the Junos OS image on a device that has one or more custom YANG modules added to it, you must remove all configuration data corresponding to the custom YANG data models from the active configuration. After the software installation is complete, add the YANG packages and corresponding configuration data back to the device, if appropriate. The tasks are outlined in this topic.
You do not need to delete configuration data corresponding to OpenConfig packages before upgrading or downgrading Junos OS.
Backing up and Deleting the Configuration Data
If the configuration contains dependencies on custom YANG data models:
Restoring the YANG Packages and Configuration Data
After the software installation is complete, load the YANG packages onto the device (where required), and restore the configuration data associated with the packages, if appropriate. During a software upgrade or downgrade, devices running Junos OS with upgraded FreeBSD preserve custom YANG packages, whereas devices running Junos OS based on FreeBSD version 6 delete the packages.