When you enable the ESXi Shell or SSH on a particular host in a vSphere cluster, a warning will appear on a ESX host:

ESXi Shell for the host has been enabled

or SSH for the host has been enabled

This is normal behaviour, but you can turn off these warnings for each of the hosts.

Note that prior to vSphere 4.1 Update 2, it is not possible to suppress the warnings.

Open vSphere Client.

Select the ESX host. From the Configuration tab (right pane), click Advanced Settings.

Navigate to UserVars → UserVars.SuppressShellWarning.Set its value to 1.

Click OK to confirm. The warning will disappear immediately.

Log on to vSphere Web Client.

Select vCenter from the Home menu. Select Host  ...