One of my favorite features in vCenter 6.5 is the built-in Update Manager. VMware Update Manager (VUM) 6.5 is used to patch and upgrade vSphere ESXi hosts, virtual appliances, VMware Tools, and virtual hardware. Previous versions of the vCenter Server Appliance required a separate Windows machine to run Update Manager. For many admins, this was a deterrent in deploying VUM. Now that the embedded Update Manager leverages the vCenter Server Appliance Postgres database, there is no additional vms to install or management items to configure. Update Manager has proved to be tremendously handy in keeping environments properly updated.

If you are looking to upgrade your ESXi to vSphere 6.5, Update Manager is a solid choice. This post will focus on the process of upgrading ESXi 6.0 to 6.5 utilizing VUM.

This may go without saying, but before beginning, ensure your vCenter Appliance is at version 6.5.

To start the process, navigate to Update Manager from the vCenter Server Appliance Web Client.

Update Manager (VUM)

Import ESXi Image

Let’s begin by importing our 6.5 ESXi Image. To do so, select the vCenter Server under Navigator. Click the Manage tab, navigate to ESXi Images, and finally click Import ESXi Image.

ESXi Images

Browse to the ESXi Image location and select the ISO. Once selected, the upload process will begin.

Browse ESXi Image

After uploaded, you will be provided a review of the ESXi Image information.

ESXi Import

Create Baseline

Next, we will add this Image as a Baseline. Navigate to the Host Baselines tab and select New Baseline.

New Baseline

The New Baseline wizard will begin. Enter the Name and Baseline Type. In this instance, we will choose Host Upgrade.

Baseline Type

Next, select the uploaded ESXi Image to upgrade.

Baseline ESXi Image

Review your selections and click Finish when ready.

Baseline ESXi Review

We have uploaded the Image and the Baseline is created. Our next step will be to Attach the Baseline to the cluster.

Attach Baseline

Select Go to Compliance View to begin.

Compliance View

With your cluster selected, choose Attach Baseline.

Attach Baseline

Select the pertinent Upgrade Baseline.

Upgrade Baseline

This next step is optional, but if you would like to verify the compliance of your Baseline, select Scan for Updates.

Compliance Check


In our last step, we will set our Remediation Options and begin the Remediation process. Click the Remediate Button to begin.


Select the correct Baseline to remediate.

Remediate Baseline

Select the Host(s) for remediation.

Remediate Hosts

Read and Accept the EULA.

Remediate EULA

In the Advanced Options section, we can schedule a specific time to run the remediation and/or choose to ignore unsupported items. For this, we will leave both unchecked.

Remediate Advanced

Next, specify maintenance mode options. The first option will be determining what you want to be done with machines when the host enters into maintenance mode. We want to do this without vm downtime, so we will leave VM Power state at Do Not Change VM Power State. Options for disabling removable media and retrying maintenance mode can also be changed.

Remediate Options

Finally, select the pertinent cluster options you would like to apply during the remediation.

Note: For hosts in a cluster, the remediation process runs sequentially by default. If you would like to run the remediation in parallel, indicate that during this step.

Remediate Cluster

Review your selections and click Finish to start the remediation.

Remediate Review

Monitor progress from the Recent Tasks pane. The remediation process will look like this:

  • The first host is put in maintenance mode
    • VMs will be migrated to other cluster hosts
  • Host upgrade begins in background
  • Host restarts once installation is complete
  • Host reconnects to vCenter
  • Host exits Maintenance Mode
  • Remediation process moves to next host

Recent Tasks VUM

Once the remediation process is complete, your ESXi hosts will be upgraded to 6.5.