You can use a single vSphere Lifecycle Manager image to manage all ESXi hosts in a cluster. You use vSphere Lifecycle Manager images to apply software and firmware updates to the ESXi hosts.
Today, you can use various methods and tools to deploy ESXi hosts and maintain their software lifecycle. For example, you can upgrade hosts by using VMware vSphere® ESXi™ Image Builder CLI, esxcli, vSphere Auto Deploy. The different deployment and upgrade choices involve different workflows and require you to use different ESXi image formats.
When you use vSphere Lifecycle Manager images, you follow one workflow and use the same ESXi image format for all software lifecycle-related operations: install, upgrade, update, and patching, which significantly simplifies the lifecycle management process.
What Is an Image?
A vSphere Lifecycle Manager image represents a desired software specification to be applied to all hosts in a cluster. When you set up a vSphere Lifecycle Manager image, you define the full software stack that you want to run on the hosts in a cluster: the ESXi version, additional VMware software, vendor and third-party software, for example firmware and drivers. Using a single image to manage all hosts in a cluster ensures cluster-wide host image homogeneity.
The Desired State Model
The concept of images that vSphere Lifecycle Manager introduces is based on the Desired State model for managing ESXi hosts and clusters.
The desired state of an ESXi host represents both the target software and target configuration for the host as opposed to the software and configuration that it currently runs. The Desired State model is the idea of managing hosts and clusters by defining and applying a desired state instead of listing and following steps to change the current state.
What Is in an Image?
- ESXi base image
The base image is an ESXi image that VMware provides with every release of ESXi. The base image contains an image of VMware ESXi Server and additional components, such as drivers and adapters that are necessary to boot a server. Base images have a user-readable name and a unique version that is updated with every major or minor release of ESXi.
- Vendor add-on
The vendor add-on is a collection of software components that OEMs create and distribute. The vendor add-on can contain drivers, patches, and solutions.
- Firmware and drivers add-on
The firmware and drivers add-on is a special type of vendor add-on designed to assist in the firmware update process. The firmware and drivers add-on contains firmware for a specific server type and corresponding drivers. To add a firmware and drivers add-on to your image, you must install the hardware support manager plug-in provided by the hardware vendor for the hosts in the respective cluster.
- Independent components
The component is the smallest discrete unit in an image. The independent components that you add to an image contain third-party software, for example drivers or adapters.