Bootenvs¶

BootEnv Overrides¶

BootEnv overrides provide a mechanism to customize boot environments without creating multiple bootenv objects. Using the bootenv-customize parameter, you can override various aspects of bootenvs on a per-machine (via parameter inheritance) or global (via the global profile) basis.

For the complete technical reference, see Customization using bootenv-customize.

Note

The Templates section is merged with the bootenv's templates, with identically-named templates from the parameter overriding the bootenv templates
You must use the per-arch SupportedArchitectures section to override kernel, initrd, ISO, boot parameter, and bootloader values

Warning

This is not compatible with bootenv purging and may cause UI pauses when uploading ISOs
Avoid creating multiple overrides for the same bootenv with the same OS name but different ISOs or kernel/initrd settings
Do not override sledgehammer on a per-machine basis - any overrides for sledgehammer must be matched by identical changes in the OS section of the discovery bootenv (discovery assumes the machine can transition to sledgehammer without a reboot)

What Can Be Overridden¶

The bootenv-customize parameter allows for dynamic customizations on bootenvs. You can override the following bootenv fields:

Loaders - Override bootloader files for different architectures (key-value map)
OS - Override OS metadata and architecture-specific settings
Name - Operating system identifier
Version - OS version number
Codename - OS codename (e.g., esxi, alma, rocky)
Family - OS family classification
SupportedArchitectures - Architecture-specific configurations including:
- IsoFile - ISO filename to use
- IsoUrl - URL to download the ISO file
- Sha256 - ISO checksum for validation
- Kernel - Kernel file path
- Initrds - List of initrd file paths
- Loader - Architecture-specific loader path
- BootParams - Kernel boot parameters
Templates - Override or add template configurations (array of template objects)
Name - Template name (required)
Path - Path where template will be rendered
ID - Template ID to reference
Contents - Inline template contents
Link - Link to template resource
Meta - Template metadata (key-value map)

Structure¶

The parameter is structured as a map of bootenv name to override values:

YAML

Params:
  bootenv-customize:
    <bootenv-name>:
      Loaders:
        <arch-type>: <loader-path>
      OS:
        Name: <os-name>
        Version: <version-string>
        Codename: <os-codename>           # optional
        Family: <os-family>               # optional
        SupportedArchitectures:
          <arch>:
            IsoFile: <iso-filename>
            IsoUrl: <iso-download-url>    # optional
            Sha256: <checksum>
            Kernel: <kernel-path>
            Initrds:
              - <initrd-path>
            Loader: <loader-path>         # optional
            BootParams: <boot-parameters>
      Templates:
        - Name: <template-name>           # required
          Path: <template-path>
          ID: <template-id>               # optional, mutually exclusive with Contents
          Contents: <inline-template>     # optional, mutually exclusive with ID
          Link: <template-link>           # optional
          Meta:                           # optional
            <key>: <value>

Automated Profile Generation¶

The drpcli profiles genbootenv command can automatically generate bootenv override profiles from a CSV file, useful for managing multiple ISO versions:

Bash

drpcli profiles genbootenv --csvFile /path/to/versions.csv --outputDir /path/to/output

CSV format (first 5 columns required, additional columns become custom params):

Text Only

Name,IsoFile,Sha256,BootEnv,Version,param1,param2
profile-name,os-installer.iso,checksum-here,base-bootenv,version,value1,value2

This generates profiles with complete bootenv-customize parameters automatically. See drpcli profiles genbootenv --help for full usage details.

Use Cases¶

BootEnv overrides are particularly useful for:

Multiple ISO versions - Support different versions of the same OS without creating separate bootenvs
- VMware Custom ISO - Complete example
- ESXi Getting Started Guide - Provisioning workflow
- OpenShift RHCOS Customization - Content pack generator
Sledgehammer versioning - Pin specific Sledgehammer versions for discovery
- Example bootenvs-customize with Sledgehammer - Complete example
- Updating Sledgehammer - Version management
Bootloader customization - Switch bootloaders for specific hardware or security requirements
- How dr-provision Boots Machines - Architecture details
- Secure Boot Shim Bootloaders Fail With Proxy DHCP - Workaround details

To Do¶

Describe bootenv iso building
Describe kickstart/preseed usage
Describe runner.tmpl inclusion
Describe kernel parameters