Updating kernel packages and applying OS update packages

This section explains how to update a kernel package or apply an OS update package on a host on which HDLM is installed.

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A kernel package refers to any package named "kernel-xxx.rpm". An OS update package refers to any package named "initscripts-xxx.rpm" or "lvm2-xxx.rpm". (In each of the aforementioned package names, xxx represents the version number.)

You can also update a kernel package or apply an OS update package in single user mode.

If you create an initial RAM disk image file for HDLM, specify a file name that is supported by the kernel after the kernel is upgraded. In addition, if you edit the boot loader configuration file, copy the startup settings of the SCSI device that was added after the kernel update, and then change the definition so that the OS starts in a state in which HDLM is configured.

Notes when using the kernel to handle CPU vulnerabilities (by using the retpoline method)

There are no notes for Red Hat Enterprise Linux 8 or Red Hat Enterprise Linux 9.

Note the following when performing a version upgrade of the kernel in Red Hat Enterprise Linux 7 when HDLM is installed:

• Upgrading from a version of the kernel that supports the retpoline method to another version that also supports the retpoline method

  There are no restrictions regarding CPU vulnerabilities.

• Upgrading from a version of the kernel that does not support the retpoline method to another version that does not support the retpoline method

  There are no restrictions regarding CPU vulnerabilities.

• Upgrading from a version of the kernel that does not support the retpoline method to a version that supports the retpoline method

  Perform the following procedure:

  1. If you are using a version of HDLM that is earlier than version 8.6.2, perform an upgrade installation of HDLM.

  2. Upgrade the version of the kernel, and then start the upgraded kernel.

  3. Reinstall HDLM.

• Upgrading from a version of the kernel that supports the retpoline method to a version that does not support the retpoline method

  This type of upgrade is not supported.

For details about whether the kernel supports the retpoline method, see HDLM-SUPPORTED_KERNELS_THAT_HANDLE_CPU_VULNERABILITIES_BY_THE_RETPOLINE_METHOD=GUID-50CA17D6-7737-4065-A9DF-5687683C680F=1=EN=.html. For further details, consult with the OS provider.

The following table shows whether version upgrades are supported, using Red Hat Enterprise Linux 7.3 as an example.

Table. Combinations of the retpoline-compatible kernels that can be upgraded when HDLM is installed

Kernel currently in use	The kernel after upgrade
	Red Hat Enterprise Linux 7.3 With the retpoline method supported	Red Hat Enterprise Linux 7.3 With the retpoline method unsupported	Red Hat Enterprise Linux 7.4 With the retpoline method supported	Red Hat Enterprise Linux 7.4 With the retpoline method unsupported
Red Hat Enterprise Linux 7.3 With the retpoline method unsupported	Y#	Y	Y#	Y
Red Hat Enterprise Linux 7.3 With the retpoline method supported	Y	--	Y	--

Legend:

Y: Upgrade is possible

--: Not applicable

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You must perform the procedure described in "Upgrading from a version of the kernel that does not support the retpoline method to a version that supports the retpoline method".

The following table lists the sections you can refer to for procedures that apply to different OSs and installation environments.

#1

For combinations of kernel versions for which a version upgrade cannot be performed while HDLM is installed.

These combinations are those indicated by an N in Table 3.

#2

For combinations of kernel versions for which a version upgrade cannot be performed while HDLM is installed.

These combinations are those indicated by an N in Table 4.

#3

For combinations of kernel versions for which a version upgrade can be performed while HDLM is installed.

These combinations are those indicated by a Y in Table 3.

#4

For combinations of kernel versions for which a version upgrade can be performed while HDLM is installed.

These combinations are those indicated by a Y in Table 4.

#5

For combinations of kernel versions for which a version upgrade can be performed while HDLM is installed.

These combinations are those indicated by a Y in Table 5.

Legend:

Y: Upgrade is possible

N: Upgrade is not possible (due to incompatibility with the HDLM driver)

--: Not applicable

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• Kernel downgrades are not supported.

• The installed version of HDLM must support the upgraded kernel version.

• To upgrade from a kernel version that does not support the retpoline method to a version that supports the retpoline method, you must use HDLM 8.6.2-00 or a later version.

Legend:

Y: Upgrade is possible

N: Upgrade is not possible (due to incompatibility with the HDLM driver)

--: Not applicable

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• Kernel downgrades are not supported.

• The installed version of HDLM must support the upgraded kernel version.

• If the upgraded kernel version is Red Hat Enterprise Linux 8.8 or later, the value of multipath_component_detection in the /etc/lvm/lvm.conf file must be set to 0 to disable it.

Legend:

Y: Upgrade is possible

N: Upgrade is not possible (due to incompatibility with the HDLM driver)

--: Not applicable

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• Kernel downgrades are not supported.

• The installed version of HDLM must support the upgraded kernel version.