# Linux OS Imaging

This section describes the supported Linux distributions and guides for deploying Linux on bare metal using Morpheus. It includes validated OS versions, required virtual image settings, boot loader configuration for unattended installation, and troubleshooting steps for common deployment issues (see Section Troubleshooting for more details).

The following Linux distributions have been validated for deployment:

- Red Hat Enterprise Linux (RHEL) and derivatives

  - RHEL 9.5
  - Oracle Linux 8.10
  - Oracle Linux 9.5
- Ubuntu Server

  - Ubuntu Server 22.04.5 LTS
  - Ubuntu Server 24.04.3 LTS

## Virtual Image Configuration

When adding a Linux ISO to Library > Virtual Images, ensure the following settings:

- Operating System: Select the appropriate OS (e.g., RHEL 9, Oracle Linux 9, Ubuntu 22.04, Ubuntu 24.04)
- Is Cloud Init Enabled: Checked
- Advanced

  - VM Tools Installed: Checked

## Boot Prompt Configuration - RHEL and Oracle Linux

Unmodified RHEL and Oracle Linux ISOs include a default boot menu entry: `Test this media & install OS`.

This entry performs a **full media verification** before installation.

NOTE

- The media check does not cause installation failure.
- It can, however, delay deployment by 30–60 minutes, particularly in remote or virtual media environments.
- Skipping the media check is recommended to reduce installation time.

**Supported Options**

- Preferred: Modify the ISO
  - Adjust the ISO boot loader to remove or bypass the media check from the default boot entry.
  - Ensures faster, fully unattended deployment.
- Alternative: Manual Boot Selection
  - At boot: Select `Install OS` (without media test).
  - Do NOT select `Test this media & install OS`.
- **Reference**
  - Grub menu example (for clarity):
  - `0 → Install Red Hat Enterprise Linux 9.5`
  - `1 → Test this media & install Red Hat Enterprise Linux 9.5`
  - Default entry index `1` triggers the media check.
- Changing the default to `0` or manually selecting `Install OS` skips verification.

  
![Test media and install](https://support.hpe.com/hpesc/public/api/document/sd00007732en_us/GUID-65FC9E75-A386-4A4A-A6BE-591A95640685-high.png)

## Boot Prompt Configuration - Ubuntu Server

Ubuntu Server requires kernel boot parameters to enable unattended installation using cloud-init autoinstall.

Unmodified ISOs do not automatically perform unattended installation.

## Required Manual Step (Unmodified ISO)

At the GRUB boot menu:

- Highlight the default Ubuntu entry.
- Press **e** to edit.
- Append the following kernel parameters: `autoinstall ds=nocloud`
- Boot with the modified entry.
- Example Boot Entry:

  ```
  ```
  menuentry "Ubuntu" {  
      set gfxpayload=keep  
      linux   /casper/vmlinuz quiet autoinstall ds=nocloud ---  
      initrd  /casper/initrd  
  }
  ```
  ```

This enables cloud-init–based unattended installation.

## Licensing and Registration

After installation, register the OS to receive updates and support.

Table 1. License and Registration

     | Distribution | Registration Reference | Notes |
| --- | --- | --- |
| RHEL | [Red Hat Subscription-Manager Registration Guide](https://access.redhat.com/solutions/253273?utm_source=chatgpt.com) | Use `subscription-manager` to register and attach subscriptions. |
| Oracle Linux | [Registering Oracle Linux System with ULN](https://docs.oracle.com/en/engineered-systems/exadata-database-machine/dbmmn/registering-oracle-linux-system-uln.html?utm_source=chatgpt.com) | Use the `uln_register` tool to register with Oracle Unbreakable Linux Network. |
| Ubuntu | [Ubuntu 24.04 LTS Release Notes](https://discourse.ubuntu.com/t/ubuntu-24-04-lts-noble-numbat-release-notes/39890) | Ubuntu does not require mandatory registration. An optional Ubuntu Pro subscription provides extended security maintenance and support. |
