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 version in a series of releases. You can easily replace the current image of a cluster with the recommended image for that cluster.

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 elementsvSphere Lifecycle Manager generates recommendations automatically under certain conditions and upon certain events. Alternatively, you can trigger recommendation generation manually.

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 the latest and most appropriate image for your environment.

You can manually cancel the recommendation generation task from the Recent Tasks pane.

What Does Latest in Current Series Mean

The recommendation that vSphere Lifecycle Manager generates is based on the major ESXi version in the image that the cluster uses. vSphere Lifecycle Manager recommends the most recent ESXi version that causes no hardware compatibility issues or regressions. The ESXi version in the recommended image is always within the major release series of the ESXi version of the image for the cluster.

The latest image in a series contains the latest minor ESXi version or patch for that version. For example, if the current image for a cluster contains a base ESXi image of version 7.0 and base images of version 7.0 Update 1, 7.0 Update 2, 7.0 Update 3, and 8.0 are available in the vSphere Lifecycle Manager depot, the latest image in the current series recommendation contains ESXi version 7.0 Update 3.

In some cases, 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 any other image element, for example the vendor add-on, a component, or the firmware add-on.

Why Are Some ESXi Versions not Recommended

The latest ESXi major version available in the depot might not be recommended, because it might be in conflict with upgrade path restrictions or because it causes hardware compatibility issues. Images that are not recommended contain ESXi versions that, if used for a cluster, might lead to regressions.

For example, the current image for a cluster contains a base ESXi image of version 7.0 Update 1 and the vSphere Lifecycle Manager depot contains ESXi images of version 7.0 Update 2, a hot patch for 7.0 Update 2, and 8.0. Upgrading to the ESXi 7.0 Update 2 with the hot patch is an allowed upgrade path. Upgrading further to ESXi 8.0 causes regression, because the recommended image that contains ESXi 8.0 does not contain the hot patch. So, vSphere Lifecycle Manager lists ESXi Update 2 with the hot patch as the latest in current series recommendation. ESXi 8.0 is listed as a not recommended ESXi version.

In some cases, vSphere Lifecycle Manager might list as not recommended an ESXi version within the current release series. The reason is possible hardware compatibility issues.

In the vSphere Client, you can view a list of all ESXi versions that are not recommended for use together with an explanation about the reason why they are not recommended.

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.

    Note:

    If the depot gets updated with solution components only, vSphere Lifecycle Manager does not generate new recommendations. Similarly, if the depot gets updated by adding or removing base images that are of a major ESXi version as compared to the current image of a cluster, vSphere Lifecycle Manager does not start a recommendation generation task.

  • You edit the image that you use for a cluster and save the new image set-up.
    Note:

    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.

Check for Recommended Images

By using recommended images for your clusters or standalone hosts, you ensure that your environment runs the latest verified software. Although vSphere Lifecycle Manager generates image recommendation automatically when the cluster or the host changes or when new software is available in the vSphere Lifecycle Manager depot, you can manually check for recommendations at any time.

A recommended image contains updates for your cluster or host. The recommendations is based on the ESXi versions available in the vSphere Lifecycle Manager depot. When you trigger the Compute image recommendations task, vSphere Lifecycle Manager first determines the recommended ESXi version for the cluster or host. After that, vSphere Lifecycle Manager checks sequentially for newer versions of the vendor add-on, additional components, and firmware add-on that are compatible with the recommended ESXi version and the hardware of the hosts in the cluster or the standalone host. So, sometimes, a recommended image might contain the same ESXi version as the ESXi version in the current image for the cluster or host but combined with an updated vendor add-on, component, or firmware add-on.

The Compute image recommendations task is non-cancellable. You must rerun the task periodically to ensure that the recommendations are valid and still suitable to the cluster or host.

Before you check for recommended images, you must ensure that the cluster or host is not being remediated. Recommendations generation and remediation are mutually exclusive operations. They cannot run simultaneously.

Prerequisites

Procedure

  1. In the vSphere Client, navigate to a cluster or a standalone host that you manage with a single image.
  2. On the Updates tab, select Hosts > Image.
  3. In the Image card, click the horizontal ellipsis icon and select Check for recommended images.
    When the task finishes, a blue badge appears in the Image card.
  4. To view the recommended images, click the horizontal ellipsis icon and select View recommended images.

Results

vSphere Lifecycle Manager suggests a recommended image for the cluster or for the standalone host or reports that no recommended images are available for the cluster or the host. When no recommended images are available, vSphere Lifecycle Manager displays detailed information about why no recommendations are available or why certain ESXi versions are not recommended.

What to do next

View the recommendations. You can import a recommended image to the cluster or host and replace the current image that the cluster or the host uses. See Use the vSphere Lifecycle Manager Recommended Image as the New Image for a Cluster or a Standalone Host.

View the Recommended or Not Recommended Images for a Cluster or a Standalone Host

You can view the pre-validated image that vSphere Lifecycle Manager recommends for a cluster or a standalone host and also the ESXi versions that vSphere Lifecycle Manager does not recommend for that cluster or host because of possible hardware compatibility issues or regression.

Prerequisites

Procedure

  1. In the vSphere Client, navigate to a cluster or a standalone host that you manage with a single image.
  2. On the Updates tab, select Hosts > Image.
  3. If no recommendations are available for the cluster or host at all, click View Details in the banner at the top of the pane to see details.
  4. If recommendations are available, in the Image card, click the horizontal ellipsis icon and select View recommended images.
    • To view the image that vSphere Lifecycle Manager recommends for the cluster or the host, check the Latest in current series column in the Recommended Images dialog box.
    • To view the ESXi versions that vSphere Lifecycle Manager doesn't recommend for the cluster or the host, in the Recommended Images dialog box, click Show versions that are not recommended.
      Note: The Show versions that are not recommended link is visible only if the vSphere Lifecycle Manager depot contains more recent ESXi versions than the ESXi version in the current cluster or host image, but those more recent versions are not within the major release series of the current base image or might lead to hardware compatibility issues. For example, if the image for your cluster or host contains ESXi version 7.0, and ESXi 8.0 is available in the vSphere Lifecycle Manager depot, the latter is listed as a not recommended version.
    If the View recommended images option is dimmed, no recommended images are available for this cluster or host. If recommendations are available, in the Image card, you see a label indicating the number of recommendations.
    The Recommended Images dialog box appears.

What to do next

You can decide to use the recommended image and set it as the new image for the cluster or the host.

Use the vSphere Lifecycle Manager Recommended Image as the New Image for a Cluster or a Standalone Host

For any cluster or host that you manage with a single image, you can view the images that vSphere Lifecycle Manager recommends and you can replace the current image for the cluster or the host with a recommended image. Using recommended images saves you the time and effort of identifying valid images that are applicable to all hosts in a cluster or to a standalone host.

Prerequisites

Procedure

  1. In the vSphere Client, navigate to a cluster or to a standalone host that you manage with a single image.
  2. On the Updates tab, select Hosts > Image.
  3. In the Image card, click the horizontal ellipsis icon and select View recommended images.
    If the View recommended images option is dimmed, no recommended images are available for this cluster or host.
    The Recommended Images dialog box appears.
  4. In the Recommended Images dialog box, select a recommended image by clicking the respective radio button and click Continue.
    The recommended image is based on the latest ESXi version within the current release series. For example, if the ESXi version in your current image is 7.0, this option might include ESXi version 7.0 Update 3 and a related vendor add-on. The recommended image cannot contain ESXi 8.0 or any other minor release version within the 8.0 release series.
    The selected image is imported to the cluster or the standalone host as a draft. The Edit Image card appears.
  5. (Optional) Edit the image and validate the new image set-up.
  6. Click Save.
    If you do not save the image, it is saved as a draft. The next time you start editing the image for that cluster or host, you can use the draft as a starting point.

Results

The recommended image is saved for that cluster or host. If a draft exists for the cluster or the host, the draft is overridden by the recommended image. No software is installed on the hosts in the cluster or on the standalone host at this stage.

What to do next

To apply the software specification that the image defines, remediate the cluster or the host against the new image. See Run a Remediation Pre-Check for a Cluster, a Host Within a Cluster, or a Standalone Host and Remediating a Cluster or a Standalone Host Against a Single Image.