Upgrading the kernel on a root encapsulated system
Prev Rootability Next

Upgrading the kernel on a root encapsulated system

OS vendors often release maintenance patches to their products to address security issues and other minor product defects. They may require customers to regularly apply these patches to conform with maintenance contracts or to be eligible for vendor support. Prior to this release, it was not possible to install a kernel patch or upgrade on a root encapsulated system: it was necessary to unencapsulate the system, apply the upgrade, then reencapsulate the root disk. It is now possible to upgrade the OS kernel on a root encapsulated system.

Note:

The procedures in this section only apply to minor kernel upgrades or patches. These procedures do not apply to a full upgrade of the Linux operating system.

To upgrade the OS kernel on a root encapsulated system

  1. Apply the minor upgrade or patch to the system.
  2. After applying the upgrade, run the commands:
    # . /etc/vx/modinst-vxvm
    # upgrade_encapped_root

    The above commands determine if the kernel upgrade can be applied to the encapsulated system. If the upgrade is successful, the command displays the following message:

    # upgrade_encapped_root
The VxVM root encapsulation upgrade has succeeded.
Please reboot the machine to load the new kernel.

    After the next reboot, the system restarts with the patched kernel and a VxVM encapsulated root volume.

Some patches may be completely incompatible with the installed version of VxVM. In this case the script fails, with the following message:

# upgrade_encapped_root
FATAL ERROR: Unencapsulate the root disk manually.
VxVM cannot re-encapsulate the upgraded system.

The upgrade script saves a system configuration file that can be used to boot the system with the previous configuration. If the upgrade fails, follow the steps to restore the previous configuration.

Note:

The exact steps may vary depending on the operating system.

To restore the previous configuration

  1. Interrupt the GRuB bootloader at bootstrap time by pressing the space bar.

    The system displays a series of potential boot configurations, named after the various installed kernel versions and VxVM root encapsulation versions.

    For example:

    Red Hat Enterprise Linux Server (2.6.18-53.el5)
Red Hat Enterprise Linux Server (2.6.18-8.el5)
vxvm_root_backup
vxvm_root
  2. Select the vxvm_root_backup option to boot the previous kernel version with the VxVM encapsulated root disk.

To upgrade the OS kernel on a root encapsulated system using manual steps

  1. If the upgrade script fails, you can manually unencapsulate the root disk to allow it to boot.

    See Unencapsulating the root disk.

  2. Upgrade the kernel and reboot the system.
  3. If the reboot succeeds, you can re-encapsulate and remirror the root disk.

    See Encapsulating and mirroring the root disk.

    However, after the next reboot, VxVM may not be able to run correctly, making all VxVM volumes unavailable. To restore the VxVM volumes, you must remove the kernel upgrade, as follows:

    # rpm -e upgrade_kernel_package_name

    For example:

    # rpm -e kernel-2.6.18-53.el5
Prev Up Next
Allocation of METADATA Subdisks During Root Disk Encapsulation Home Administering an encapsulated boot disk