Guest environment
This document provides an overview of the guest environment, which containsscripts, daemons, and binaries that instances need to run onCompute Engine.
The guest environment communicates with the metadata server, which is aper-instance HTTP server that runs alongside every Compute Engineinstance. The metadata server provides the instance with essential configurationand operational data. For more information about the types of metadata that'sstored on the metadata server, seeVM metadata.
The guest environment is automatically installed on Compute Engine instancesthat are created by using most of the Google-provided public operating system(OS) images. Each OS image requires specific guest environment packages.These packages are built either by Google or the operating system distributor.For a full list of OS images that include the guest environment,seeOperating system details.
Guest environment components
The following section describes the packages and services that enable aninstance to communicate with Compute Engine.
The guest agent
The central component of the guest environment is the guest agent, which handlestasks like account management, OS Login integration, and network interfacemanagement. The guest agent is available for both Linux and Windows operatingsystems, with the following package names:
- Linux:
google-guest-agent - Windows:
google-compute-engine-windows
For detailed information about the guest agent,including its features, architecture, and how to manage the agent, seeGuest agent.
Linux components
The base components of a Linux guest environment aredeb orrpmpackages. Compute Engine creates these packages with the appropriate configurations for thesupported distribution. To see the list of installed packages on your Linuxinstance, connect to the instance, and run the command provided for your OSversion in theInstalled packages by operating system versiontable.
The Linux guest environment includes the following key packages.
| Package name | Description | Key interactions | Link to source code on GitHub |
|---|---|---|---|
google-guest-agent | This package is the guest agent for the Linux environment. The Linux guest agent contains the scripts that run on the guest OS to support Compute Engine features. For detailed information about the guest agent,including its features, architecture, and how to manage the agent, seeGuest agent. |
| guest-agent |
google-compute-engine | Contains the scripts and files required for system initialization and configuration. This package contains the following:
| Works with the following packages to configure instances.
| guest-configs |
google-compute-engine-oslogin | Contains the necessary binaries, modules, and scripts to manage instance access using OS Login. OS Login lets you manage access to instances by using IAM roles. For more information about OS Login, seeOS Login. This package contains the following:
|
| guest-oslogin |
gce-disk-expand | Contains the components required for resizing a boot disk. | Sends logs to the serial port | gce-disk-expand |
google-osconfig-agent | Contains the OS Config agent, which VM Manager uses to manage OS inventory, patches, and policies. For more information about the OS Config agent, seeVM Manager. | Reads data from and writes data to theVM metadata By default, the OS Config agent doesn't collect or send any information until youenable the OS Config agent. After you enable the agent, the agent communicates with the OS Config API service. To review the operations completed by the agent, seeVM Manager audit logging. | guest-osconfig |
Windows components
All Google-provided Windows OS images are preconfigured with theGooGet tool and Google Cloud repositories.GooGet installsand maintains the guest environment for Windows instances. If you needto installGooGet and set up repositories, seePackagingand package distribution in thecompute-image-windows GitHub repository. To seethe list of installed packages on your Windows instance, connect to the instance and rungooget installed.
The Windows guest environment includes the following key packages:
| Package name | Description | Key interactions | Link to source code on GitHub | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
google-compute-engine-windows | This package is the guest agent for the Windows environment. The Windows guest agent contains the scripts that run on the guest OS to support Compute Engine features. For detailed information about the guest agent,including its features, architecture, and how to manage the agent, seeGuest agent. |
| guest-agent | ||||||||||||||
google-compute-engine-sysprep | Contains scripts forgeneralizing a Windows instance in preparation for creating an OS image. The package also includes theinstance_setup.ps1 script that runs on first boot to configure the new instance. |
| sysprep | ||||||||||||||
google-compute-engine-metadata-scripts | Contains scripts and binaries that run |
| google_metadata_script_runner | ||||||||||||||
google-compute-engine-powershell | Contains a PowerShell module. This module provides common functions that PowerShell scripts in the other Windows guest environment scripts use. | Sends logs to the Windows Application Event Log and the serial port | PowerShell | ||||||||||||||
google-compute-engine-auto-updater | Contains scripts that update the Compute Engine packages daily. This package isn't installed by default. This approach lets you maintain the stability of your environment by controlling the update process. If your environment can tolerate updates without disruption, you can install this package to ensure your guest environment packages are updated automatically. To install this package, use the following command: |
| auto_updater | ||||||||||||||
google-compute-engine-diagnostics | Contains a binary thatcollects diagnostic information from the instance and saves the information to a Cloud Storage bucket. The Windows guest agent executes the binary. | Saves data to a Cloud Storage bucket | diagnostics | ||||||||||||||
certgen | Contains a binary that creates a certificate on the instance. | certgen | |||||||||||||||
GooGet | Contains a binary that installs and maintains the guest environment for Windows instances. | Reads data from the Google Cloud repositories located atpackages.cloud.google.com | GooGet | ||||||||||||||
google-compute-engine-vss | Installs the Compute Engine VSS agent and provider that takespersistent disk snapshots using Microsoft'sVolume Shadow Copy Service (VSS) | Communicates with the Google Cloud snapshot service | vss | ||||||||||||||
google-osconfig-agent | Contains the OS Config agent, which VM Manager uses to manage OS inventory, patches, and policies. For more information about the OS Config agent, seeVM Manager. | Reads data from and writes data to theVM metadata By default the OS Config agent doesn't collect or send any information until youenable the OS Config agent. After you enable the agent, the agent communicates with the OS Config API service. To review the operations the agent completes, seeVM Manager audit logging. | guest-osconfig | ||||||||||||||
| Compute Engine Windows drivers | Contains several drivers to ensure proper functionality and performance of instances. The The following Compute Engine drivers are maintained for Windows OS images:
To install or upgrade a specific driver, run the following command: googet installDRIVER_PACKAGE_NAME | compute-windows-drivers |
What's next
- Learn how toInstall the guest environment.
- Learn about theguest agent.
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Last updated 2025-12-15 UTC.