In Cloud Foundation 4.0, you can use cluster images as an alternative way of performing ESXi host lifecycle operations. A cluster image represents a desired software specification to be applied to all hosts in a vSphere cluster. Software and firmware updates happen simultaneously, in a single workflow.
A cluster image is a precise description of the software, components, vendor add-ons, and firmware to run on a host. With this new functionality, you set up a single image and apply it to all hosts in a cluster, thus ensuring cluster-wide host image homogeneity.
Cluster Image and vSphere Lifecycle Manager
Cluster images are made available by the vSphere Lifecycle Manager (vLCM), a vCenter service. This service is now integrated with Cloud Foundation and enables centralized and simplified lifecycle management of ESXi hosts. When a VI workload domain or cluster is created with an image, you can update and upgrade the ESXi software on all hosts in a cluster. You can also install driver add-ons, components, and firmware on the hosts.
For more information on cluster images (also referred to as vSphere Lifecycle Manager Images), see vSphere Lifecycle Manager Images.
Cluster Image Components
A cluster image may consist of four elements: ESXi base image, a vendor add-on, a firmware and drivers add-on, and additional components. It is mandatory to add ESXi to a cluster image. Adding the other elements is optional.
- ESXi base image
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.
- Vendor Add-On
A vendor add-on is a collection of software components for the ESXi hosts that OEMs create and distribute. This vendor add-on can contain drivers, patches, and solutions.
A component is the smallest discrete unit in an image, created and published by third-party software vendors.
Firmware refers to firmware and drivers add-on, 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.
Cluster Image in Cloud Foundation
Cluster images must be created in vSphere 7.0 and then imported to Cloud Foundation. Unlike vSphere where cluster images are managed per cluster, Cloud Foundation allows you to manage all cluster images in a single place and re-use them for clusters across workload domains.
You can create an image either on the management domain vCenter Server, or a vCenter Server external to Cloud Foundation. Since an image is created for a cluster of hosts, you must create a vLCM-enabled cluster and then create an image for that cluster. While creating the image, you specify the ESXi version and can also select vendor add-ons, components, or firmware for the image.
After the image is created in vSphere, you export the cluster image specification and component files from vSphere to your local computer. You then import these files to Cloud Foundation so that you can apply the image to a vLCM-enabled VI workload domain.
After you import an image to Cloud Foundation, it can be customized when it is applied to a cluster. For example, say your image included only the base ESXi image. When you use this image to create a VI workload domain, NSX-T components are added to the default cluster during the domain creation. You may also add vendor-adds, components, or firmware to the workload domain cluster. You can now extract the updated image from this cluster and reuse it for other similar clusters in this workload domain or in other workload domains.
Cluster Image Workflow
Cluster Images are Optional for Workload Domains
- vLCM (vSphere Lifecycle Manager) automates the lifecycle management of your Cloud Foundation environment including firmware by using cluster images.
- vSphere Update Manager (VUM) also automates the lifecycle management of your Cloud Foundation environment but firmware updates are manual. The management domain is VUM-based.