The Pre-Check Remediation is a check that is performed on the host or the cluster that displays a table that lists possible problems that might prevent a successful remediation, and a recommendation on how to fix the issues.
When you generate a pre-check remediation report, Update Manager generates a list with recommended actions you must perform to ensure a successful remediation of the hosts in your cluster.
You can generate a pre-check remediation report from both vSphere Client and the vSphere Web Client.
In the vSphere Client, you can generate a pre-check remediation report by selecting a host or a cluster from the inventory, and navigating to the Updates tab. In the top-right corner, there is a pre-check remediation card from where you can generate the report.
In the vSphere Web Client, you can generate a pre-check remediation report when you create a remediation task for hosts that are contained in a cluster. You generate the report from the Cluster Remediation Options page of the Remediate wizard.
| Current Configuration/Issue | Recommended Action | Details |
|---|---|---|
| DRS is disabled on the cluster. | Enable DRS on the cluster. | DRS enables vCenter Server to place and migrate virtual machines automatically on hosts to attain the best use of cluster resources. |
| vSAN health check fails during the pre-check. | Navigate to the vSAN Health page and address any health issues before proceeding with remediation. | The vSAN health check performs a series of tests on the hosts in the vSAN cluster. The vSAN health check must succeed to ensure the hosts are successfully remediated. If you start a remediation task in a vSAN cluster that failed the vSAN health check during the remediation pre-check, the hosts enter maintenance mode, get upgraded, but might fail to exit maintenance mode. The remediation eventually fails. |
| DPM is enabled on the cluster. | None. Update Manager disables DPM automatically. |
If a host has no running virtual machines, DPM might put the host in standby mode before or during remediation and Update Manager cannot remediate them. |
| HA admission control is enabled on the cluster. | None. Update Manager disables HA admission control automatically. |
HA admission control prevents the migration of virtual machines with vSphere vMotion and the hosts cannot enter maintenance mode. |
| EVC is disabled on the cluster. | Enable EVC manually. | If EVC is disabled for a cluster, the migration of virtual machines with vSphere vMotion cannot proceed. The result is downtime of the machines on the hosts that you remediate with Update Manager. This issue is displayed only in the vSphere Web Client. |
| Current Configuration/Issue | Recommended Action | Details |
|---|---|---|
| A CD/DVD drive is attached to a virtual machine on the ESXi host. | Disconnect the CD/DVD drive. | Any CD/DVD drives or removable devices connected to the virtual machines on a host might prevent the host from entering maintenance mode. When you start a remediation operation, the hosts with virtual machines to which removable devices are connected are not remediated. |
| A floppy drive is attached to a virtual machine on the ESXi host. | Disconnect the floppy drive. | Any floppy drives or removable devices connected to the virtual machines on a host might prevent the host from entering maintenance mode. When you start a remediation operation, the hosts with virtual machines to which removable devices are connected are not remediated. |
| Fault Tolerance (FT) is enabled for a virtual machine on the ESXi host. | None. Update Manager disables FT automatically. |
If FT is enabled for any of the virtual machines on a host, Update Manager cannot remediate that host. |
| VMware vCenter Server is installed on a virtual machine on the ESXi host and DRS is disabled on the cluster. | Enable DRS on the cluster and ensure that virtual machines can be migrated with vSphere vMotion. | One of the virtual machines in the cluster runs the vCenter Server instance that you currently use. If you enable DRS on the cluster, vSphere vMotion can migrate the virtual machine where vCenter Server runs to ensure that the remediation of the hosts is successful. |
| VMware vSphere Update Manager is installed on the virtual machine and DRS is disabled on the cluster. | Enable DRS on the cluster and ensure that virtual machines can be migrated with vMotion. | One of the virtual machines in the cluster runs the Update Manager instance that you currently use. If you enable DRS on the cluster, vMotion can migrate the VM where Update Manager runs to ensure that the remediation process of the hosts in the cluster is successful. |
