To understand the difference between vSphere Lifecycle Manager images and vSphere Lifecycle Manager baselines, you must understand the relation between the basic software packaging types that software vendors use to create and ship software updates.

vSphere Lifecycle Manager uses software from VMware, OEMs, and third-party software providers.
  • OEMs are VMware partners, for example, Dell, HPE, VMware Cloud on AWS.
  • Third-party software providers are providers of I/O filters, device drivers, CIM modules, and so on.

vSphere Installation Bundles (VIBs)

The VIB is the basic building block for the creation of installation packages for ESXi hosts. A VIB is a software package that contains metadata and a binary payload, which represents the actual piece of software to be installed on ESXi. The VIB does not represent an entire feature, but just a single module of the feature. So, the VIB is the smallest installable software unit that VMware and other software vendors ship.

vSphere Lifecycle Manager does not consume and work with individual VIBs. VIBs must be further packaged into a higher-level construct.

VIB Metadata
An XML file ( descriptor.xml) that describes the contents of the VIB. It also contains dependency information, textual descriptions, system requirements, and information about bulletins.
Standalone VIB
A VIB that is not included in a component.

Bulletins

The bulletin is a grouping of one or more VIBs. Bulletins are defined within the metadata of the VIB. You use bulletins, and not individual VIBs, to create vSphere Lifecycle Manager baselines, which you attach to inventory objects and use to update and upgrade ESXi hosts.
Patch
A small software update that provides bug fixes or enhancements to the current version of the software. A patch groups one or more VIBs together to address a particular issue or to provide enhancements to the current version of the software.
Roll-up Bulletin
A collection of patches that is grouped to facilitate downloads and deployment.
Extension
A bulletin that defines a group of VIBs for adding an optional component to an ESXi host. An extension is usually provided by a third party. The third-party provider is also responsible for providing patches, or updates, for the extension.

Components

The component is a bulletin with additional metadata specifying the name and the version of the component. Unlike the bulletin, the component is a logical grouping of VIBs, which provides you with a complete and visible feature upon installation. Starting with vSphere 7.0, the component becomes the basic packaging construct for VIBs. VMware, OEMs, and third-party software providers now deliver software in the form of components.

However, VMware and OEMs do not deliver components indepednently. VMware bundles components together into fully functional ESXi base images. OEMs bundle components together into vendor add-ons.

Third-party software vendors create and ship software, for example drivers or adapters, as independent components.

Bulletins or Components?

vSphere Lifecycle Manager can consume both bulletins and components.

If you use baselines and baseline groups to manage hosts and clusters, vSphere Lifecycle Manager reads and lists the software updates that are available in the vSphere Lifecycle Manager depot as bulletins. You can find the list of available bulletins on the Updates tab in the vSphere Lifecycle Manager home view.

If you use vSphere Lifecycle Manager images to manage hosts and clusters, you can only work with components and the related notions of add-ons and base image. You can find the list of the components, add-ons, and ESXi base images on the Image Depot tab in the vSphere Lifecycle Manager home view.