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Chapter 9. General Updates

Incorrect information about the expected default settings of services in Red Hat Enterprise Linux 7

The module of Preupgrade Assistant that handles initscripts provides incorrect information about the expected default settings of the services in Red Hat Enterprise Linux 7 according to the /usr/lib/systemd/system-preset/90-default.preset file in Red Hat Enterprise Linux 7 and according to the current settings of the Red Hat Enterprise Linux 6 system. In addition, the module does not check the default settings of the system but only the settings for the runlevel used during the processing of the check script, which might not be the default runlevel of the system. As a consequence, initscripts are not handled in the anticipated way and the new system needs more manual action than expected. However, the user is informed about the settings that will be chosen for relevant services, despite the presumable default settings. (BZ#1366671)

Installing from a USB flash drive fails on UEFI systems

The efidisk.img file is required to create a bootable USB drive that will work on a system with UEFI firmware. In this release, a problem during the compose build process has caused this file to be generated incorrectly, and as a result, the file is not usable for booting.
As a workaround, use one of the alternate means of booting the installer on UEFI systems:
  • Burn one of the provided boot ISO images (boot.iso or the full installation DVD) to a CD or DVD, and boot using an optical drive
  • Mount one of the ISO images as a CD or DVD drive
  • Set up a PXE server and boot from the network (BZ#1588352)

In-place upgrade from a RHEL 6 system to RHEL 7.6 is impossible with FIPS mode enabled

When upgrading a RHEL 6 system to RHEL 7.6 using the Red Hat Upgrade Tool with FIPS mode enabled, missing Hash-based Message Authentication Code (HMAC) prevents kernel data from being correctly verified. As a consequence, the Red Hat Upgrade Tool cannot boot into the target system kernel and the process fails. To work around this problem, disable FIPS mode by removing fips=1 from the kernel command line and re-enable it after the upgrade. (BZ#1612340)

In-place upgrade on IBM Z is impossible if the LDL format is used

The Linux Disk Layout (LDL) format is unsupported on RHEL 7. Consequently, on the IBM Z architecture, if a partition is formatted with LDL on one or more Direct Access Storage Devices (DASD), the Preupgrade Assistent indicates this as an extreme risk, and the Red Hat Upgrade Tool does not start the upgrade process to prevent a data loss on such a partition.
To work around this problem, migrate to the Common Disk Layout (CDL) format. To check which DASD format is in use, run:
# dasdview -x <disc>
The command output will show the following result for the CDL format:
format : hex 2 dec 2 CDL formatted
or this result for the LDL format:
format : hex 1 dec 1 LDL formatted
Note that without applying the RHBA-2019:0411 update, a data loss can occur because the Preupgrade Assistant was previously unable to detect the LDL format.