VMware ESXi and vSphere Cluster Management

What Is a Virtual Machine Template in VMware vCenter Server?

Learn what VMware vCenter Server virtual machine templates are, why they improve provisioning, and when to use Clone to Template or Convert to Template.

A virtual machine template is a reusable master image for deploying consistent virtual machines. In VMware environments, vCenter Server manages templates and uses them to provision new VMs on VMware ESXi hosts.

A template usually contains a prepared guest operating system, baseline applications, virtual hardware settings, and organization-specific configuration choices. Instead of repeating the same operating system and application installation for every server, an administrator prepares one reference build and uses it as the starting point for many VMs.

What Is a Virtual Machine Template?

A virtual machine template is a stored, reusable copy of a prepared VM configuration and its virtual disks. It represents a master image: an approved baseline that can be used repeatedly during provisioning.

The VM used to prepare that image is called the reference VM. Before creating the template, an administrator normally installs and configures the guest operating system, adds approved software, applies standard settings, and removes or avoids information that should not be duplicated between servers.

Typical template contents

Guest operating system: The operating system installed inside the VM, such as a supported Windows Server or Linux release.
Baseline applications: Common agents, management tools, runtime components, or other software required on most servers.
Virtual hardware: Standard CPU, memory, disk, network adapter, and other VM configuration choices.
Operating system configuration: Approved security, networking, service, and system settings.
Standardized build choices: The organization’s selected OS edition, disk layout, application versions, and configuration baseline.

A template is different from an ordinary VM. A standard VM is a runnable virtual computer that can host applications and services. A template is reserved for creating or deploying VMs and cannot be powered on while it remains in template form.

Why Use Virtual Machine Templates?

Templates make repeated provisioning faster. Provisioning means creating and configuring a new VM for use. Once a template is available, an administrator can deploy a new VM without manually installing the same operating system and baseline applications from the beginning.

Faster deployment: A new server starts from an existing image rather than a blank virtual disk.
Consistency: New VMs begin with the same approved operating system, applications, and configuration.
Fewer manual errors: Repeating installation and configuration steps manually creates opportunities for omissions and differences.
Standardization: Teams can define and maintain an approved server build for common workloads.
Reduced administration effort: Common setup work is performed once in the reference VM instead of once per server.

A template does not eliminate all deployment work. Each resulting VM may still need a unique name, identity, network configuration, application role, and other workload-specific settings. vCenter Server can also support guest OS customization during deployment; see Customize Guest OS.

Template Lifecycle in vCenter Server

1. Prepare the reference VM

Begin with a normal VM, called the reference VM. Install the intended guest operating system and apply the organization’s approved build configuration. Add common applications and configure standard virtual hardware, security settings, and management components.

For a Windows Server example, an administrator might build a Windows Server 2022 VM, install required updates and common monitoring software, apply the organization’s baseline settings, and verify that the VM meets the approved server standard. The resulting build is the candidate master image.

Before capturing the template, check that the reference VM does not contain server-specific values that should be unique, such as a production hostname or workload-specific network identity. Plan how each deployed VM will receive its unique settings.

2. Create the template in vCenter Server

With the reference VM prepared and in the appropriate state, use the vCenter Server inventory action that creates a template. There are two primary methods: Clone to Template and Convert to Template.

The choice matters because it determines whether the original reference VM remains available as a normal VM.

3. Deploy new VMs from the template

When a server is needed, select the template in the vCenter Server inventory and choose the workflow to deploy a new VM from it. The workflow generally asks where to place the VM, which compute resource and datastore to use, what name to assign, and whether to apply guest OS customization.

The deployment creates a normal VM based on the template. That VM can then be powered on, customized for its role, and run on an ESXi host. For a related workflow, see Deploy VM From Template.

4. Convert the template back when changes are required

Templates have restrictions compared with ordinary VMs. A template cannot be powered on, and direct changes to its VM settings are limited or unavailable. If the master image needs an operating system update, application change, or hardware adjustment, convert the template back to a VM first.

Convert the template back to a normal VM.
Power on and modify the VM as required.
Test the updated reference build.
Convert it back to a template, or create a new template copy.

This cycle allows the master image to be maintained without treating the template itself as a running server.

Clone to Template

Clone to Template creates a separate template from the selected reference VM. The original VM remains in the vCenter Server inventory as a normal, runnable VM.

Use this method when the source VM must remain available. For example, the source might be a working reference server, a testable baseline, or a VM that must continue to provide a service while a reusable template is created. The related concept of copying a VM is covered in Clone a Virtual Machine.

Typical workflow

Prepare and shut down or otherwise place the reference VM in the state required by your organization’s image process.
In the vCenter Server inventory, select the VM and choose the action to clone it to a template.
Provide the template name and select its inventory location and storage placement.
Complete the task and verify that both the original VM and the new template are present.

Convert to Template

Convert to Template changes the selected source VM into a template. The source is no longer retained as a normal, runnable VM after the conversion.

Use this method when the prepared reference VM exists solely to become the master image. It avoids retaining a second copy as a normal VM, but it also means that the original VM is no longer available for ordinary workload use.

Typical workflow

Prepare and validate the reference VM.
In the vCenter Server inventory, select the VM and choose the action to convert it to a template.
Confirm the conversion and verify that the inventory object is now identified as a template.
Deploy new VMs from the template as needed.

Clone to Template vs. Convert to Template

Method	What happens to the source VM	Result	Best use case
Clone to Template	The source VM is retained.	A separate reusable template is created.	Use it when the original VM must remain operational or be kept as a reference VM.
Convert to Template	The source VM becomes a template.	No separate runnable source VM remains.	Use it when the prepared source VM is intended only to become the master image.

Virtual Machine and Template Comparison

Capability	Standard virtual machine	Virtual machine template
Can be powered on	Yes, subject to normal inventory and resource requirements.	No. It remains a deployment source while in template form.
Can serve as the source for deployment	It can be cloned or used as a source for some provisioning workflows.	Yes. This is its primary purpose.
Can be directly used as a workload	Yes. It can run an operating system and applications.	No. Deploy a VM from it first.
How configuration changes are handled	Settings can normally be edited according to permissions and VM state.	Convert it back to a VM before making required changes, then update or recreate the template.

Example: Standard Windows Server Deployment

Suppose an organization repeatedly deploys Windows Server 2022 for internal application servers.

Build the reference VM: Create a VM with the organization’s standard CPU, memory, disk, and network configuration. Install Windows Server 2022 as the guest operating system.
Apply the standard: Install required updates and common applications, configure approved security and management settings, and verify the baseline.
Capture the master image: Use Clone to Template if the reference VM must remain available, or Convert to Template if it exists only for image creation.
Deploy future servers: Deploy separate VMs from the template, select the appropriate ESXi compute and datastore locations, and apply unique guest OS and server settings.
Complete role configuration: Configure each new VM for its specific application or service, then test it before placing it into production.

The result is a set of Windows Server VMs that share a known starting point. Administrators still customize each server’s identity and workload settings, but they do not repeat the entire base installation and configuration process.

Maintaining a Template Safely

A template is only useful while its contents remain appropriate. Establish a maintenance process that identifies the operating system release, baseline application versions, and date of the image. When the baseline changes, update the reference VM, test it, and publish an updated template according to your organization’s change process.

Keep production-specific names, credentials, and network identities out of the reusable baseline.
Document the guest operating system and included applications.
Test a deployed VM before using an updated template broadly.
Use clear names or version labels so administrators can distinguish current and retired templates.
Store templates on appropriate datastores and plan capacity for their virtual disks. For vSAN storage concepts, see Datastore In Virtual SAN.

Troubleshooting Common Template Problems

The template cannot be powered on

Cause: A template is not a runnable workload. Its purpose is to provide a source for deployment.

Resolution: Deploy a new VM from the template and power on that VM. If the master image itself needs modification, convert the template back to a VM first.

Template settings cannot be edited directly

Cause: Template format has restrictions that do not apply to a standard VM.

Resolution: Convert the template to a VM, make and test the required changes, then convert the updated VM back to a template or create a new template with Clone to Template.

The original VM is missing after template creation

Cause: Convert to Template was used. That action changes the source VM into the template rather than producing a separate copy.

Resolution: In future, use Clone to Template when the source VM must be retained. Choose the method deliberately before confirming the inventory action.

Exam-Relevant Summary

A virtual machine template is a reusable master image for consistent VM provisioning.
It can include a guest operating system, applications, virtual hardware settings, and standardized build choices.
A template cannot be powered on while it remains a template.
Deploying from a template produces a normal VM that can run on VMware ESXi.
Clone to Template retains the source VM and creates a separate template.
Convert to Template changes the source VM into a template, so no normal source VM remains.
Convert a template back to a VM before making changes to the master image.

For foundational platform context, review the VMware ESXi Online Course, and for management connectivity see Communication Between vCenter Server and ESXi.