Guest environment release notes

This page documents updates to the guest environment, which is a set of scripts, daemons, and binaries that read metadata server content to ensure instances function correctly on Compute Engine. The central component of the guest environment is the guest agent, which handles tasks like account management, OS Login integration, and network interface management. For more information about the guest environment, see Guest environment.

Check this page for announcements about new or updated features, bug fixes, known issues, and deprecated functionality.

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March 05, 2026

Feature

Version 20260228.00 of the guest agent is now available for Debian 12, AlmaLinux 9, CentOS Stream 9, Oracle Linux 9, Red Hat Enterprise Linux 9, and Rock Linux 9. To review the features and fixes included in version 20260228.00 of the guest agent, see the March 2, 2026 release notes.

March 04, 2026

Feature

Version 20260228.00 of the guest agent is now available for Windows. To review the features and fixes included in version 20260228.00 of the guest agent, see the March 2, 2026 release notes.

March 03, 2026

Feature

Version 20260228.00 of the guest agent is now available for Debian 11, AlmaLinux 8, CentOS Stream 8, Oracle Linux 8, Red Hat Enterprise Linux 8, and Rock Linux 8. To review the features and fixes included in version 20260228.00 of the guest agent, see the March 2, 2026 release notes.

March 02, 2026

Fixed

Version 20260228.00 of the guest agent includes the following fixes:

  • The guest agent is now able to add users to the Administrator group on different locales on Windows.
  • The guest agent now signals itself ready only after the network setup has fully completed. This should prevent the guest agent from hitting race conditions with custom routing solutions that depend on the guest agent service.
  • The guest agent no longer spams metadata SSH key errors when a key is incorrectly formatted.
  • The guest agent now ensures proper reconnection of the primary NIC after a configuration rollback, specifically when NetworkManager is active. This resolves an issue where the NIC might not come back online in such scenarios.
  • The guest agent now applies the value of the following configuration flags correctly: Daemons.network_daemon and NetworkInterfaces.vlan_setup_enabled.
Feature

Version 20260228.00 of the guest agent is now available for Debian 13, AlmaLinux 10, CentOS Stream 10, Oracle Linux 10, Red Hat Enterprise Linux 10, and Rock Linux 10. This version introduces the following features:

  • Supports bootstrapping credentials for the HTTPS endpoint for the metadata server by default. For more information about the HTTPS metadata server endpoint, see HTTPS metadata server endpoints.
  • Includes a cleanup job that runs once a day and each time the guest agent manager service initializes. This cleanup job ensures that leftover plugin files and states are properly cleaned up.
  • Supports dynamically starting locally installed extensions. This feature is disabled by default, but it can be toggled by setting the enable_local_plugins flag to true in the guest agent configuration file.

December 18, 2025

Fixed

Version 20251218.00 of the guest agent is now available for Windows only. This version includes the following fixes:

  • Fixes a crash loop in VM extensions due to a race condition where the guest agent manager service can sometimes try to connect to the extension before it is able to create and bind to its unix socket.
  • Fixes an issue where the core plugin is not creating required registry keys before attempting to write to them.

December 11, 2025

Feature

Version 20251209.00 of the guest agent, which re-introduces the plugin-based architecture to Windows, is now available.

For more information about the plugin-based architecture, see Guest agent.

The plugin-based architecture for Windows was previously rolled back due to a bug that prevented the correct setup of IP alias routes when used with the WSFC module, see October 21, 2025 release notes.

December 08, 2025

Feature

Version 20251205.00 of the guest agent is available for Linux only. This version includes the following feature:

  • Snapshot module now supports using NGUIDs to identify disks supporting a wider range of VM families.
Fixed

Version 20251205.00 of the guest agent is available for Linux only. This version includes the following fixes:

  • Fixes an issue where the metadata server would become inaccessible during the dynamic removal of multiple vLAN NICs.
  • Fixes an issue where the metadata script runner failed to parse all supported URL patterns and formats.
  • Rolls back multi-universe support for the Agent Communication Service (ACS) client due to issues in the default universe.

November 20, 2025

Feature

Version 20251120.01 of the guest agent is now available for Windows only. This version includes the following fix:

  • Changes the start mode guest agent from auto to delayed-auto on Windows Service Manager.

November 17, 2025

Feature

Version 20251115.00 of the guest agent is now available.

Fixed

Version 20251115.00 of the guest agent is now available and includes the following fixes:

  • Fixes an issue in the dynamic vLAN subsystem where the dhclient backend attempted to remove netplan's vLAN NICs.
  • Fixes a crash loop in the plugin manager caused by its handling of plugin logs.

November 13, 2025

Feature

Version 20251107.01 of the guest agent is now available.

Fixed

Version 20251107.01 includes a fix for the Startup script runner component that prevented it from writing status logs and script output to Cloud Logging.

October 31, 2025

Fixed

Version 20251030.02 includes fixes for the plugin-based architecture that is used by guest agent. For more information about the plugin-based architecture, see Guest agent.

  • The Clock Skew module no longer causes time inconsistencies on VMs. The agent no longer attempts to synchronize the hardware clock (hwclock) when the VM's Real-time Clock (RTC) isn't set to Coordinated Universal Time 0(UTC). For more information about how the guest agent handles clock synchronization, see Clock Synchronization.
  • The vlan_setup_enabled option now correctly sets up Dynamic Network Interfaces (NICs). Dynamic NICs now initialize reliably.
  • The agent now prevents a race condition in network interface and route setup. Previously, routes were temporarily flushed if they were added before a DHCP lease was acquired. The agent now ensures routes persist correctly, preventing a brief period of missing routes. These routes were previously auto-corrected after approximately one minute.

October 21, 2025

Fixed

Version 20251009.01 of the guest agent, announced in the October 20, 2025 release notes, has been rolled back. This version introduced the plugin-based architecture to Windows but contained a bug in the WSFC module. To resolve this issue, guest agent version 20251011.00 is now available for Windows, which excludes the new plugin-based architecture.

October 20, 2025

Feature

Version 20251009.01 of the guest agent, which introduces the plugin-based architecture to Windows, is now available.

For more information about the plugin-based architecture, see Guest agent.

October 02, 2025

Feature

Version 20250930.01 of the guest agent, which introduces the plugin-based architecture to Debian 11, is now available.

For more information about the plugin-based architecture, see Guest agent.

September 30, 2025

Fixed

Version 20250930.01 includes the following fixes for issues found in the plugin-based architecture. For more information about the plugin-based architecture, see Guest agent.

  • Fixes an issue where the networking module incorrectly added routes when ip_forwarding and target_instance_ips settings were disabled in /etc/default/instance_configs.cfg.
  • Prevents unnecessary error logs in the OS Login module caused by attempts to read a non-existent file.

September 26, 2025

Feature

Version 20250926.00 of the guest agent is now available. This guest agent version introduces the plugin-based architecture to Debian 12.

For more information about the plugin-based architecture, see Guest agent.

September 18, 2025

Feature

Version 20250918.01 of the guest agent is now available. This guest agent version introduces the plugin-based architecture to the following Debian and Enterprise Linux 10 operating systems:

  • Red Hat Enterprise Linux (RHEL) 10
  • Rocky Linux 10
  • CentOS Stream 10
  • Debian 13

For more information about the plugin-based architecture, see Guest agent.

Fixed

Version 20250918.01 includes the following fixes for issues found in plugin-based architecture. For more information about the plugin-based architecture, see Guest agent.

  • Corrects an issue in the OS Login module that was incorrectly writing perm_denied=die PAM module configuration when two-factor authentication isn't enabled.
  • Fixes an issue in the metadata-based SSH module where re-adding a user didn't add the user to the sudoers group.

September 09, 2025

Fixed

Version 20250907.00 includes the following fixes for issues found in guest agent version 20250901.00:

  • Corrects an issue in the OS Login module that was incorrectly handling optional runtime systemd dependencies and causing an error log.
  • Fixes a bug that could cause the metadata SSH key module to enter an infinite loop when setting up SSH keys. This occurred if an initial setup attempt failed and the metadata server returned the SSH keys in a different order on a subsequent retry.
Feature

Version 20250907.00 of the guest agent, which introduces the plugin-based architecture to Enterprise Linux 8 operating systems, is now available. For more information about the plugin-based architecture, see Guest agent.

With this version, the plugin-based guest agent is now also available for the following operating systems:

  • Red Hat Enterprise Linux (RHEL) 8
  • Rocky Linux 8
  • CentOS Stream 8
  • Oracle Linux 8
  • AlmaLinux 8

September 03, 2025

Feature

With the introduction of the plugin-based architecture, the guest agent includes the following updates:

  • A new command-line tool, ggactl_plugin, is available to manage and restart the guest agent core plugin. To restart the agent, run:

    ggactl_plugin coreplugin restart

    For more information, see Restarting the guest agent.

  • All guest agent components now use a new logging framework. This framework lets you set the logging level in the guest agent configuration file. For more information about the logging options, see core settings in the configuration options table.

  • The workload refresh service gce-workload-cert-refresher is now part of the guest agent's core plugin. It is no longer a separate systemd service.

  • The guest agent updates the metadata script runner and the Authorized Keys binary (Windows only) to use the new, configurable logging framework. Compatibility managers are included to facilitate the migration.

Announcement

Starting with version 20250901.00, the guest agent is migrated to a new plugin-based architecture to improve modularity. You can revert to the previous version by setting the metadata attribute enable-guest-agent-core-plugin to FALSE. For more information about the plugin-based architecture, see Guest agent.

This plugin-based guest agent is available for the following operating systems:

  • Red Hat Enterprise Linux (RHEL) 9
  • Rocky Linux 9
  • CentOS Stream 9
  • Oracle Linux 9
  • AlmaLinux 9
Fixed

An issue is fixed where network routes were not consistently applied (GitHub Issue #516). The system now consistently applies network routes by monitoring the route table and re-adding routes when they disappear.