The os-forward-compat-12 package is a temporary compatibility package used during upgrades from BSD12-based Junos OS releases to BSD15-based Junos OS releases.
os-forward-compat-12
During a Junos OS upgrade, the device can validate the existing configuration against components of the target software before the new software is activated. During a BSD12 to BSD15 transition, some components of the BSD15-based target release require system calls that are not available in the BSD12 kernel.
os-forward-compat-12 provides the additional system-call compatibility required for those components to execute while the device is still running the BSD12 kernel. This enables configuration validation to be performed before the upgrade proceeds.
The package is used only when required for this compatibility function and is not intended for normal runtime operation. It deactivates when it is no longer required.
os-package
os-package and os-forward-compat-12 perform different functions during the upgrade.
Updates the package-management functionality of the currently running Junos OS release. A sufficiently recent os-package can be required so that the source system can correctly handle os-forward-compat-12 during configuration validation.
See TSB70152 [juniper.net]: os-package recommendation for Junos OS software upgrades on BSDx platforms for information about os-package.
Provides the runtime compatibility required during configuration validation by adding system-call support needed by BSD15-based components while the system is still running the BSD12 kernel.
For applicable BSD12 to BSD15 upgrade paths, both functions therefore have a role:
Source Junos OS running BSD12
When os-forward-compat-12 is included in the Junos OS image and the source system meets the applicable package-management requirements, no manual installation of os-forward-compat-12 is required.
During configuration validation, the system can:
This is the expected behavior when os-forward-compat-12 is available for the applicable upgrade path.
If os-forward-compat-12 is required but is unavailable or cannot be activated, configuration validation during an upgrade from a BSD12-based release to a BSD15-based release can fail.
The upgrade might consequently require configuration validation to be resolved before proceeding or require use of the no-validate option to bypass configuration validation.
no-validate
Before performing an applicable BSD12 to BSD15 Junos OS upgrade:
Review TSB70152 [juniper.net] and ensure that the source Junos OS system meets the applicable os-package requirements.
Follow the normal software upgrade procedure for the target Junos OS release.
If os-forward-compat-12 is included in the target Junos OS image, no separate manual installation of the package is required. The package is automatically used during configuration validation when needed.
If configuration validation requires os-forward-compat-12 but the package is not included with the target software, obtain the appropriate package through JTAC.
os-forward-compat-12 is not available for direct customer download.
Copy the package to /var/tmp and install it using:
/var/tmp
After installation, the package is used automatically during configuration validation when required.
If the compatibility package cannot be obtained or used and configuration validation cannot be completed, the Junos OS upgrade can be performed with the no-validate option.
The no-validate option bypasses configuration compatibility validation. Because the existing configuration is not validated against the target Junos OS release before the upgrade proceeds, this option should be used only when configuration validation cannot be completed.
Contact JTAC if assistance is required to determine the appropriate upgrade procedure.
os-forward-compat-12 is a temporary compatibility mechanism used during the BSD12 to BSD15 upgrade process.
The package: