For the clusters that you manage with images, vSphere Lifecycle Manager can generate and provide you with software recommendations in the form of pre-validated images that are compatible with the hardware of the hosts in a cluster. Recommended images are valid images that are based on the latest ESXi major or minor release.

When you set up or edit an image, you manually combine the image elements (ESXi version, vendor add-on, firmware add-on, and additional components) in such a way as to define the full software stack to run on all hosts in the cluster. You must manually check whether a particular image set-up is complete and valid, and suitable to your environment. The vSphere Lifecycle Manager recommendations save you the effort of exploring the possible and applicable combinations of image elements.

Recommended images are validated through a series of checks that ensure that a recommended image has no missing dependencies or conflicting components. For vSAN clusters, the validation also runs a hardware compatibility check against the vSAN Hardware Compatibility List (vSAN HCL). The extensive validation checks ensure that if you decide to use a recommended image for a cluster, the remediation against the recommended image is successful.

To generate recommendations, vSphere Lifecycle Manager checks what software is available in the vSphere Lifecycle Manager depot and what firmware is available in the depot that the selected hardware support manager makes available. Based on the available software, firmware, and, for vSAN clusters, the hardware compatibility checks, for each cluster that you manage with a single image, vSphere Lifecycle Manager provides you with up to two recommended images.
  • Latest image

    The latest image contains the latest major ESXi version. For example, if the current image for a cluster contains a base image of version ESXi 7.0 and base images of version 7.5 and 8.0 are available in the vSphere Lifecycle Manager depot, the latest image recommendation contains ESXi version 8.0.

  • Latest image in the current series

    The latest image in a series contains the latest minor ESXi. For example, if the current image for a cluster contains a base image of version ESXi 7.0 and base images of version 7.0a, 7.0 U1, 7.5, and 8.0 are available in the vSphere Lifecycle Manager depot, the latest image in the current series recommendation contains ESXi version 7.0 U1.

The ESXi version in a recommended image might be the same as the ESXi version in the current image for a cluster. But the recommended image might contain a later version of the vendor add-on, component, or firmware add-on.

Sometimes, the latest ESXi version available in the depot might not be recommended, because it causes hardware compatibility issues. In that cases, vSphere Lifecycle Manager reports that no recommended images are available for the cluster.

You can replace the current image of a cluster with one of the recommended images for that cluster.

The recommendation generation task is cancelable.

Automatically Triggered Recommendation Generation

vSphere Lifecycle Manager generates a new image recommendation automatically in the following cases.
  • The vSphere Lifecycle Manager depot gets updated.

    By default, the depot updates every 24 hours. Also, the content of the depot changes when you import an offline bundle to the depot or you manually trigger synchronization to the configurable download sources.

  • You edit the image that you use for a cluster and save the new image set-up.
Note: If the depot gets updated with solution components only, vSphere Lifecycle Manager does not generate new recommendations. Similarly, if you edit an image by only adding solution components to the image, vSphere Lifecycle Manager generates no new recommendation.

The automated recommendation generation is available only for clusters that already have recommended images generated. When vSphere Lifecycle Manager starts the generation of a new recommendation automatically, the Compute Image recommendations for cluster task appears in the Recent tasks pane. You can observe the progress of the task or cancel it. vCenter Server issues an event when a recommendation generation task starts or ends. If the task fails, vCenter Server issues an alarm of the warning type. In cases of failure, you must check for recommended images for the cluster manually. The recommendation generation task cannot run simultaneously with other vSphere Lifecycle Manager operations, for example remediation and compliance checks. If you need to start another operation immediately, you can cancel the Compute Image recommendations for cluster task at any time.

In ROBO deployments, the automatically triggered recommendation generation is possible only if the local depot and the central vSphere Lifecycle Manager depot are synchronized.