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.

Table 1. Related Terminology
Term Definition
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 bulletin or component.

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


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.
Table 2. Related Terminology
Term Definition
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 are 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 and updates for the extension.


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. 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 that provides you with a complete and visible feature upon installation.

VMware and OEMs do not deliver components independently. VMware bundles components together into fully functional and bootable 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.

Base Images

The base image is an ESXi image that VMware provides with every release of ESXi. The base image is a collection of components that is complete and can boot up a server. Base images have a user-readable name and a unique version that is updated with every major or minor release of ESXi.

The version of a base image corresponds to an ESXi release and uses the following naming format:
  • General Availability release: 7.0
  • Update release: 7.0 U1, 7.0 U2
  • Patch release: 7.0 a, 7.0 b
  • Security patch release: 7.0 sa, 7.0 sb
  • Patch after an update release: 7.0 U1 a, 7.0 U1 sa, 7.0 b, 7.0 sb

Base images are hosted and available in the VMware online depot. Additionally, you can download an ESXi installer ISO file and an offline bundle (ZIP file) that contains the ESXi version from

Vendor Add-Ons

OEMs pack one or multiple components into a unit called an add-on. You use vendor add-ons to customize an ESXi image with OEM content and drivers.

The add-on is a collection of components that does not represent a complete, bootable image. You cannot use vendor add-ons on their own. To customize an ESXi release, you must add the vendor add-on to an ESXi base image. The combination of a vendor add-on and an ESXi base image is practically identical to an OEM-provided custom image.

When combined with an ESXi base image, the add-on can add, update, or remove components that are part of the ESXi base image. In the vSphere Client, for each add-on available in the depot, you can view the list of components that it adds to an ESXi base image. Similarly, you can find information about the components that it removes from a base image.

Starting with vSphere 7.0, in addition to custom ISO images and offline bundles, OEMs can release ZIP files that contain only the vendor add-on, that is, the delta between the custom image and the ESXi base image. OEMs can release such add-on ZIP files at their discretion. The introduction of the concept of add-ons decouples the release cycle of OEMs from the release cycle of VMware. As a result, you can update vendor add-ons independently of updating the ESXi version of your hosts. Also, the vendor add-on decouples the OEM customization from the VMware stock image. As a result, you can combine software components more freely.

Bulletins and Components in the vSphere Lifecycle Manager Depot

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 images. 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.