Cloud scripts and cloud script templates

Release version: Xanadu

Updated June 16, 2026

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Summary of Cloud scripts and cloud script templates

In the Cloud Provisioning and Governance application within ServiceNow, scripting capabilities are divided intocloud scriptsandcloud script templates. These scripts enable automation and dynamic configuration in blueprints, resource blocks, OS profiles, and policy scripts, helping streamline virtual machine provisioning and customization. Cloud scripts are JavaScript-based and leverage platform features, while cloud script templates are executable scripts targeted for virtual machine execution.

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Cloud Scripts

Cloud scripts are JavaScript functions that interact with the platform’s templateResolver object to fetch and customize cloud script templates dynamically. Parameters within cloud scripts consist of names, default values, and override values, allowing flexible input handling. The templateResolver.getTemplate method fetches the executable template by name, using parameter values specified or overridden within the script.

Cloud scripts can be customized programmatically, for example, updating parameter values before fetching the template. This allows dynamic configuration based on external data queried via GlideRecord or other logic.

Cloud Script Templates

Cloud script templates are the actual executable scripts passed to virtual machines during provisioning. They can be of various types such as Shell, PowerShell, or CloudInit, depending on the target environment and execution context. These templates must be created separately and linked to cloud scripts for execution.

Cloud Scripts as CloudInit

CloudInit scripts are executed at virtual machine boot time and can be specified at multiple levels:

Image level: Associate a cloud script with a specific image. When a corresponding OS profile with this image is selected, the cloud script executes by default.
OS profile level: Map cloud scripts to OS profiles regardless of image. This mapping overrides image-level associations, allowing more flexible script execution across multiple images.
Resource blocks: When mapping cloud scripts to OS profiles, optionally target execution to specific resource blocks and resource aliases used in blueprints.

Cloud Scripts as Postinit

Cloud scripts can also be used as Postinit scripts within resource blocks. After provisioning a VM resource block, you can add an ExecuteScript operation that runs a selected cloud script. Script parameters can be overridden using a JSON map in the ScriptParameters attribute. This enables dynamic script customization during post-provisioning operations, supporting complex automation workflows.

Practical Benefits for ServiceNow Customers

Automate VM provisioning and configuration with reusable, parameterized scripts.
Customize script execution dynamically based on context, resource blocks, or external data.
Leverage CloudInit and Postinit scripts for flexible, environment-specific initialization tasks.
Manage script mappings at image, OS profile, or resource block levels to control execution scope precisely.

In the Cloud Provisioning and Governance application, script execution is divided into cloud scripts and cloud script templates. Use scripts in blueprints, resource blocks, OS profiles, and use policy scripts to set request form attributes. Policy scripts cannot override user data.

Cloud scripts

Cloud scripts are simple java scripts that use platform features. An example of a sample cloud script:

function evaluateTemplate() {
	// Template Resolver is a helper function which we will use to fetch a template and replace its parameters,
	// var templateResolver=new TemplateResolver(); this comes inbuild
	// templateAttributes below will passed from the user.
	var listDir=templateResolver.getTemplate('Install',templateAttributes);
	return listDir;
}

Each cloud script contains certain parameters. Parameters are the attributes that you want to access. A parameter contains a name, a default value, and an override value. The default value can be a string literal, a resource block parameter or a complex script expression used in resource blocks.

A cloud script, by default, has access to the templateResolver object. The templateResolver object has, by default, a getTemplate method, whose first parameter is the cloud script template name. templateAttributes are the cloud script parameters created as part of a cloud script. If needed, customizations can be done in templateAttributes. As an example, see the following code snippet if the value of DevName parameter needs to be changed from John to Emily.

function evaluateTemplate() {
	// Template Resolver is a helper function which we will use to fetch a template and replace its parameters,
	// var templateResolver=new TemplateResolver(); this comes inbuild
	// templateAttributes below will passed from the user.
	templateAttributes['DevName'] = 'Emily';
	var customNodeName;
	var now_GR = new GlideRecord('some_custom_table_to_query');
	gr.addQuery('some_parameter','some_value');
	gr.query();
	if(gr.next())
	 	customNodeName=gr.getValue('some_custom_node_name');
		
	templateAttributes['NodeName'] = customNodeName;
	var listDir=templateResolver.getTemplate('Install',templateAttributes);
	return listDir;
}
evaluateTemplate();

Cloud script templates

Cloud script templates are actual executables which are passed to target a virtual machine for execution. Cloud templates can be of any type (Shell/PowerShell/CloudInit) depending on the execution context. You need to create a cloud template first and then associate it with a cloud script.

Cloud scripts as CloudInit

Cloud providers provide a way to execute scripts at boottime for virtual machines. In the Cloud Management application, you can specify a cloudinit script at various levels:

Image level: At the time of creating a cloud script, you can specify an image against which this script should be executed. Once an OS profile which contains this specific image gets selected, the default cloud script against this image is executed. In the example below, an Apache cloud script is associated with a particular image.
OS profile level: You can run a cloudinit against a specific cloud provider and against a specific AMI/image. You can also be generic and associate a cloudinit to an OS profile, irrespective of the underlying image. In the following example, multiple images are associated with the OS profile. You can map any cloud script to the OS profile in the Cloud Script OS Profile Mappings tab. The mapping of a cloud script with an OS profile takes precedence over the image-level cloud script association.
In this example, the Apache cloud script is mapped to the Centos OS profile. If needed, you can override the script parameters in the OS Profile Mapping Overrides section.
Resource blocks: While mapping a cloud script to an OS profile, you can choose whether to execute the cloud script for a specific resource block used in a blueprint and against a particular resource alias. See Create an OS profile.

Cloud scripts as Postinit

You can use cloud scripts as Postinit scripts in a resource block. Once you create a resource block with a virtual machine to be provisioned, you can add an ExecuteScript operation. The ExecuteScript operation takes a script parameter (a pool of cloud scripts) and you can select any script to execute. Use the ScriptParameters attribute in the ExecuteScript operation to override any script parameter. You can provide a JSON map of script parameter and its override value. All expressions that are supported by Cloud Management work in the ScriptParamters attribute.