Contents

Rolling back the running software images· 1

Application scenarios· 1

Restrictions and guidelines· 1

Hardware-related restrictions and guidelines· 1

Software-related restrictions and guidelines· 1

Rollback workflow· 2

Rollback procedure· 2

Verifying the rollback· 2

Rolling back the running software images

This chapter includes the following sections:

·     Application scenarios

·     Restrictions and guidelines

·     Rollback workflow

·     Rollback procedure

·     Verifying the rollback

Application scenarios

The following are application scenarios for version rollback:

·     You need to roll back the running software version to the old version due to service requirements.

·     You need to roll back the running software version to the old version if the device cannot work correctly after a software upgrade.

Restrictions and guidelines

Hardware-related restrictions and guidelines

Before the version rollback, make sure the device is operating correctly, and make sure the LEDs of the power supply, fans, cards, and subcards are normal.

During the version rollback, do not power off the device, and do not restart or remove swappable modules.

If you store the startup software images in a hot swappable storage medium, do not remove the hot swappable storage medium during the startup process.

Read the release notes to verify the software and hardware compatibility and hardware restrictions for the device, cards, and subcards.

Software-related restrictions and guidelines

Before the version rollback:

·     Use the release notes to verify that the current software version can be rolled back to the target version.

·     Back up the current software images, configuration files, and login passwords to prevent data loss if the storage medium is damaged.

·     Make sure the device has sufficient storage space for the upgrade software images.

·     Make sure the CPU usage of the device or a card is not high.

·     Verify that the original configuration file before version upgrade is present on the device. If it does not exist, download the original configuration file to the device and specify it as the startup configuration file.

During the version rollback:

·     As a best practice, enable logging of the terminal to collect information.

·     A rollback requiring a device reboot will cause service interruption for the duration of the reboot.

·     Before a rollback operation is completed, no other rollback operations can be performed. Rollback operations include the install, issu, and boot-loader commands.

After the version rollback:

·     After the rollback, do not delete the running software images.

·     The upgrade of the BootWare might cause the software version to fail to be downgraded.

Rollback workflow

The version rollback workflow is the same as the version upgrade workflow. For more information, see "Upgrade workflow."

Rollback procedure

The version rollback procedure is the same as the version upgrade procedure. For more information, see "Upgrading the startup software."

If the replacement image files are still saved on the storage medium, you do not need to download them again. You only need to specify them as the startup software images.

Verifying the rollback

Verifying the rollback is the same as verifying the upgrade. For more information, see "Verifying the upgrade."