Validate the Configuration against the Installation Image
When you upgrade or downgrade the Junos OS Evolved image on a device, the system validates that the existing configuration is compatible with the new image before the actual upgrade or downgrade commences.
Before you upgrade or downgrade Junos OS Evolved on your device, you should validate the device's current configuration against the installation image you've downloaded from Juniper Networks Support .
Validation is on by default. You do not need to configure it or issue any command to start it on a device.
When you upgrade or downgrade the Junos OS Evolved image on a device, the system validates that the existing configuration is compatible with the new image before the actual upgrade or downgrade commences.
During validation, Junos OS Evolved installs the image in a temporary location and keeps this image until validation is complete. Following validation, Junos OS Evolved displays one of the following status messages:
-
Upgrade cleanup succeeded: The add operation failed, but the temporary image removal was successful. -
Upgrade cleanup failed: The add operation and the temporary image removal both failed. -
Validate cleanup succeeded: The temporary image was removed successfully. -
Validate cleanup failed: The temporary image removal failed.
Benefits of validation—If validation fails, the new image is not loaded. If you upgrade or downgrade the software on a system without validation, configuration incompatibilities between the existing and new image or insufficient memory to load the new image might cause the system to lose its current configuration or go offline.
To invoke validation manually, do one of the following:
- Issue the
request system software add image-nameoperational mode command to install the package with validation. - Issue the
request system software validateoperational mode command to just validate the configuration.