Bug 2229864

Summary: RHOSP node(s) with root disk greater than 2TiB might fail to boot with newer kernel
Product: Red Hat OpenStack Reporter: Apoorv Verma <apverma>
Component: documentationAssignee: RHOS Documentation Team <rhos-docs>
Status: NEW --- QA Contact: RHOS Documentation Team <rhos-docs>
Severity: medium Docs Contact:
Priority: unspecified    
Version: 16.2 (Train)CC: igallagh
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Hardware: x86_64   
OS: Linux   
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Description Apoorv Verma 2023-08-08 04:54:18 UTC 
Description of problem:
OSP node with root disk size greater than 2Tib might fail to boot with newer installed kernel if it's initramfs is built at a location above 2Tib from starting sector due to no free space within 2TiB of space.

Relevant documentation links with "Warning" :
[RHEL-7 8.14.4.4. Recommended Partitioning Scheme](https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/installation_guide/sect-disk-partitioning-setup-x86#sect-recommended-partitioning-scheme-x86)
[RHEL-8 B.4. Recommended partitioning scheme](https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html-single/performing_a_standard_rhel_8_installation/index#recommended-partitioning-scheme_partitioning-reference)
[RHEL-9](https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/9/html-single/performing_a_standard_rhel_9_installation/index#recommended-partitioning-scheme_partitioning-reference)

In such scenario, different "/boot" partition should be present via "Whole Disk".

The main overcloud image is a flat partition image. This means it contains no partitioning information or bootloader on the images itself.

Reference : [Appendix C. Whole Disk Images](https://access.redhat.com/documentation/en-us/red_hat_openstack_platform/13/html-single/director_installation_and_usage/index#appe-Whole_Disk_Images)

Similar warning should be present in all Red Hat OpenStack deployment documents for "root" disks size greater than 2TiB.