added rhel9.8 support for pf9ctl

[hemant300720]

ISSUE(S):

PMK-6968: Add support for RHEL9 in pf9ctl for PMK 5.18

SUMMARY

Adds RHEL 9.8 as a supported OS for pf9ctl.

• pkg/platform/centos/centos.go
  • Version(): widened the RHEL/Rocky 9.x regex from 9.[1-5] to 9.([1-5]|8) so RHEL 9.8 is recognized (Rocky's existing 9.1-9.5 range is unchanged).
  • CheckOSPackages(): same regex widening on the rocky9 version check driving package-name substitution.
  • CheckEnabledRepos(): added a new rhel9 branch (previously only centos/rhel8 were handled) that enables rhel-9-for-x86_64-baseos-rpms / rhel-9-for-x86_64-appstream-rpms via subscription-manager, mirroring the existing RHEL8 logic.
• pkg/pmk/checkNode.go: updated the "OS not supported" error message to include RHEL 9.8.

ISSUE TYPE

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that may cause existing functionality to not work as expected)
• This change requires a documentation update

IMPACTED FEATURES/COMPONENTS:

• pf9ctl check-node / prep-node OS detection and package/repo checks for RHEL/Rocky family hosts.

RELATED ISSUE(S):

• PMK-6272: Add support for Ubuntu 24.04 (analogous OS-support epic; touched pf9ctl, pf9-hostagent, pf9-kube, pf9-comms). No equivalent issues hit yet for RHEL9 beyond pf9ctl.

DEPENDS ON:

None

TESTING DONE

Automated

• go build ./... and full existing test suite (go test ./...) pass with no regressions.
• TeamCity build: #1250 (branch private/hemant/PMK-6968-rhel9-support, commit 9675e41) — 127 tests passed.

Manual

Ran end-to-end onboarding against a real RHEL 9.8 VM (test-rhel89-image, VERSION_ID="9.8") using the exact binary built by TeamCity build #1250 (verified via matching SHA-256 checksum), onboarded to DU test-du-qbert-bare-os-u20-5092390.platform9.horse:

$ pf9ctl prep-node
✓ Loaded Config Successfully
✓ Missing package(s) installed successfully
✓ Removal of existing CLI
✓ Existing Platform9 Packages Check
✓ Required OS Packages Check
✓ SudoCheck
✓ Required Enabled Repositories Check
✓ CPUCheck
✓ DiskCheck
x MemoryCheck - At least 12 GB of memory is needed on host. Total memory found: 5 GB   (unrelated hardware-sizing check, not an OS-support issue)
✓ PortCheck
✓ Existing Kubernetes Cluster Check
✓ Check if system is booted with systemd
✓ Check if firewalld service is not running
✓ Disabling swap and removing swap in fstab
✓ Completed Pre-Requisite Checks successfully
✓ Platform9 packages installed successfully
✓ Initialised host successfully
✓ Host successfully attached to the Platform9 control-plane

Confirms Required OS Packages Check and Required Enabled Repositories Check (the new RHEL9 subscription-manager repo-enable branch) both pass on real RHEL 9.8, and the host successfully attaches to the control plane. Cluster creation / pf9-kube role installation on RHEL 9.8 has not yet been validated beyond onboarding.

Reviewers