Changes

The power state of a VMware Server virtual machine can be changed either from within the guest operating system itself (for example by initiating the operating system's own shutdown command from within the VMware Remote Console) or by using the VI Web Access interface.

When a virtual machine is powered on or off, suspended, resumed or restarted it is said to have undergone a change in ''power state''. The VI Web Access interface provides no less than five locations where the power state of a virtual machine may be changed. The most prominent of these are located in the tool bar which runs along the top of the interface. Toolbar buttons are provided to power on, power off, suspend and restart the virtual machine currently selected from the ''Inventory'' panel.

If the host system is selected from the inventory panel and the ''Virtual Machines'' tab of the workspace is selected, a list of virtual machines appears together with a ''Commands'' panel. As each virtual machine is selected from this list, the ''Commands '' panel updates with a list of suitable commands, including power state changes, for the selected machine.

* '''Power Off''' - The ''Power Off'' command can be configured to immediately power down the virtual guest (an effect similar to simply removing the power from a physical computer system). The effect is immediate but also poses the risk that data will be lost given that the guest operating system running within the virtual machine is not provided the opportunity to perform a clean shutdown. If VMware Tools have been installed on the guest operating system, the ''Shut Down Guest'' option may be selected to ensure an orderly shutdown of the guest operating system prior to the removal of "virtual power" to the virtual machine.

the The ''VMware Tools Scripts'' section of the power configuration panel allows VMware Tools script execution to be disabled for each of the power state changes. To prevent a script running at a particular point, simply deselect the check box next to the corresponding description.

If a virtual machine is configured to use VMware Tools scripts then either the default scripts installed with Vmware VMware Tools, or custom scripts may be used. On Windows based guest operating systems, the default scripts take the form of Windows Batch files and are located in \Program Files\VMware\VMware Tools. On Linux guests the default scripts are shell scripts and reside in /etc/vmware-tools. On both guest types the files are descriptively named ''poweroff-vm-default'', ''poweron-vm-default'', ''resume-vm-default'' and ''suspend-vm-default''.

A review of the content of these scripts using a text or programmers programming editor will reveal that by default they actually do very little. For example, with the exception of suspend and resume, the Windows VMware Tools scripts contain nothing but a couple of comment lines. The real power of the Vmware VMware Tools scripts is the ability to configure custom scripts.

As described in the previous section, the default scripts provided may be overridden using custom scripts. Custom scripts may be created either by modifying the default scripts, or by creating new scripts and configuring VMware Tools to use the new script in place of the default script. Custom scripts may be edited using any suitable text or programming editor, or by using the ''Edit...'' button located on the ''Scripts'' tab of the Vmware VMware Tools control panel (for more details on the VMware control panel read [[The VMware Tools Control Panel]] chapter of this book). Note that the use of the control panel script editing feature on Linux will require knowledge of the ''vi'' editor. Those lacking the necessary skills with ''vi'' should consider directly creating and editing the custom scripts using their preferred editor outside the context of the control panel.

To create a custom script using the VMware Tools control panel, click on the ''Scripts'' tab and select from the menu the power change event for which the custom script is to be created from the menu. Ensure that the ''Use script'' option is selected and click on ''Custom Script'' at which point the text box containing the path to the script and the ''Browse'' and ''Edit'' buttons will be enabled. To edit the default script simply click on the ''Edit'' button and make the modification in the resulting edit window. To edit an existing custom script or create an entirely new script, enter the path and name of the script file into the the text field and press the ''Edit'' button. Once the script is complete, save the file and exit the editor to return to the control panel.

In addition to the scripts outlined above, an additional mechanism is provided on Linux, Solaris and FreeBSD guests for executing commands when a virtual machine is either shut down or rebooted. These are specified in the ''/etc'/vmware-tools.conf'' file using the '''halt-command =''' and '''reboot-command = ''' directives.