Exec

The Exec resource lets you execute scripts and commands either locally on the host machine or remotely inside containers. It provides a flexible way to automate environment setup, system configuration, and custom workflows as part of your lab sandbox, without needing to write configuration files.

Through the UI, you can define exec settings such as the script content, execution mode (local or remote), timeout, environment variables, and output handling. For remote execution, you can either create a new container or target an existing one, with support for network attachments and volume mounts.

Exec resources are ideal for tasks like installing dependencies, configuring services, running build scripts, and initializing databases during lab setup.

For more information on the exec sandbox resource, please refer to the Exec Reference documentation.

Execution modes

The exec resource supports three distinct execution modes:

• Local: runs the script directly on the host machine.
• Remote (new container): creates a new container from a specified image and runs the script inside it. Supports network attachments and volume mounts.
• Remote (existing resource): runs the script inside an already running container by selecting it from a list of existing ones. Only available when your lab already contains a container resource.

The Working Directory, Timeout, and Run As fields are shown for every mode. The Daemon switch is the only field gated by mode: it only appears in local mode.

Creating an Exec resource

Exec resources can be created in the Sandbox tab. To create a new Exec resource, navigate to the Sandbox tab and click the + button. Select Exec from the dropdown menu.

Start by naming the exec resource. Note that this is an internal name. You must provide a script to execute, and optionally configure the execution mode, timeout, environment variables, and other settings.

Setting the script

The Script field is the core of the exec resource, where you write your script directly in the code editor.

Tip

You can write key-value pairs to the $EXEC_OUTPUT file to pass data to other resources.

echo "STATUS=completed" >> $EXEC_OUTPUT

Choosing an execution mode

By default, the exec resource runs in Local mode on the host machine. To run the script remotely, choose one of:

• Remote (new container) to create a new container for execution.
• Remote (existing resource) to run the script inside an existing container.

Note

The Remote (existing resource) option is only available when your lab already contains a container resource. You must create a container before you can target it for remote execution.

Editing an Exec resource

To edit an exec resource, select it from the list of existing sandboxes in the Sandbox tab. Click on the exec resource you want to edit, make your changes in the configuration panel, and then click Add changes to save your updates. See Editing & Publishing for how changes are reviewed and published.

Configuration

Script and environment

Field	Required?	Default	Description
Script	✓		Script content to execute
Environment			Key-value pairs for environment variables

Configuration

These fields are shown for all three execution modes.

Field	Required?	Default	Description
Working Directory			Directory to execute the script in
Timeout			Maximum execution time, for example 30s, 5m

The Daemon switch is the exception: it’s only shown in local mode.

Field	Required?	Default	Description
Daemon		false	Run the script as a background daemon process

This section also includes a Run As group, shown for all three modes:

Field	Required?	Default	Description
User			Username or user ID
Group			Group name or group ID

Remote execution (new container)

These fields appear only in Remote (new container) mode.

Container

Field	Required?	Default	Description
Name	✓		Docker image name with optional tag

Selecting a custom image also reveals Username and Password fields for pulling from a private registry.

Network

Field	Required?	Default	Description
ID	✓		Reference to a network resource
IP Address			Static IP address (auto-assigned if not set)

Note

Networks must be created before they can be assigned to an exec resource. For more information on creating a network resource, please refer to the Network documentation.

Volume

Field	Required?	Default	Description
Source	✓		Source path or volume name
Destination	✓		Mount path inside the container
Read Only		false	Mount the volume as read-only

Remote execution (existing container)

This field appears only in Remote (existing resource) mode.

Field	Required?	Default	Description
Target	✓		Reference to an existing container resource

Summary

The Exec resource provides flexible script execution capabilities for automating setup tasks, system configuration, and custom workflows in your lab sandbox. You can run scripts locally on the host or remotely inside containers, either by creating a new container from an image or by targeting an existing one.

With support for environment variables, output capture, timeouts, and advanced container options like volumes, networks, and user configuration, exec resources give you fine-grained control over your lab’s automation without needing to write configuration files.