OS patch management

Use OS patch management to apply operating system patches across a set of Compute Engine VM instances (VMs). Long running VMs require periodic system updates to protect against defects and vulnerabilities.

The OS patch management service has two main components:

  • Patch compliance reporting, which provides insights on the patch status of your VM instances across Windows and Linux distributions. Along with the insights, you can also view recommendations for your VM instances.
  • Patch deployment, which automates the operating system and software patch update process. A patch deployment schedules patch jobs. A patch job runs across VM instances and applies patches.


The OS patch management service gives you the flexibility to complete the following processes:

  • Create patch approvals. You can select what patches to apply to your system from the full set of updates available for the specific operating system.
  • Set up flexible scheduling. You can choose when to run patch updates (one-time and recurring schedules).
  • Apply advanced patch configuration settings. You can customize your patches by adding configurations such as pre and post patching scripts.
  • Manage these patch jobs or updates from a centralized location. You can use the the OS patch management dashboard for monitoring and reporting of patch jobs and compliance status.


For information about pricing, see VM Manager pricing.

How OS patch management works

To use the OS patch management feature, you must set up the OS Config API and install the OS Config agent. For detailed instructions, see Setting up VM Manager. The OS Configuration service enables patch management in your environment while the OS Configuration agent uses the update mechanism for each operating system to apply patches. Updates are pulled from the package repositories (otherwise called the distribution source package) or a local repository for the operating system.

The following table summarizes the update tool and distribution source packages that are used to collect data.

Operating system Update tool Distribution source package
RHEL and Centos yum upgrade
Debian apt upgrade https://security-tracker.debian.org/tracker/data/json
Ubuntu apt upgrade https://storage.googleapis.com/ubuntu-cve-tracker/ubuntu.tar.gz
Windows Windows Update Agent Windows Update service, or the local Windows Server Update Service (WSUS)

If your VM does not have access to the updates, you must complete additional steps to allow access to the updates or patches. Consider the following options:

  • Google recommends hosting your own local repository or a Windows Server Update Service for full control over the patch baseline.
  • Alternatively, you can make external update sources available to your VMs by using Cloud NAT or other proxy services.

Patch management consist of two services: patch deployment and patch compliance. Each of service is explained in the following sections.

Patch deployment overview

A patch deployment is initiated by making a call to the Patch API (also known as the Cloud OS Config API). This can be done by using either the Google Cloud Console, gcloud command-line tool, or a direct API call. Then the Patch API notifies the OS Config agent that is running on the target VMs to start patching.

The OS Config agent runs the patching on each VM by using the patch management tool that is available for each distribution. For example, Ubuntu VMs use the apt utility tool. The utility tool retrieves updates (patches) from the distribution source for the operating system. As patching proceeds, the OS Config agent reports the progress to the Patch API.

Patch compliance overview

After you set up the VM Manager on a VM, the following takes place on the VM:

  • The OS Config agent periodically (about every 10 minutes) reports OS inventory data into guest attributes for the VM.
  • The patch compliance backend periodically reads this data, cross references it with the package metadata obtained from the OS distribution, and saves it in the Container Analysis service repository.
  • The Google Cloud Console then gets the patch compliance data from the Container Analysis API service and displays this information in the console.

How patch compliance data is generated

The patch compliance backend periodically completes the following tasks:

  1. Reads the reports that are collected from OS inventory data on a VM.
  2. Scans for classification data from the distribution source for each operating system, and orders this data based on severity (from highest to lowest).
  3. Maps these classifications (provided by the distribution source) to Google's patch compliance status.
  4. Saves the data in the Container Analysis service repository.
  5. Selects the highest severity data for each available update and shows it on the Google Cloud Console dashboard page. You can also see a full report of all available updates for the VM on the VM details page.

The following table summarizes the mapping system used to generate Google's patch compliance status.

Distribution source categories Google's patch compliance status
  • Critical
  • Urgent
Critical (RED)
  • Important
  • High
Important/Security (ORANGE)
  • Everything else
Other (YELLOW)
  • No updates available
Up-to-date (GREEN)

For example, if the OS inventory data for a RHEL 7 VM has the following package data:

  • Package name: package1
  • Installed Version: 1.4
  • Update Version: 2.0

The patch compliance backend scans for classification data (from the source distribution) and retrieves the following information:

  • Version 1.5 => Critical
  • Version 1.8 => Low
  • Version 1.9 => Low

Then on the Google Cloud Console dashboard, this RHEL 7 VM is then added to list of VMs that have a Critical update available. If you review the details for this VM, you see 1 Critical update and 2 Low updates available.

Simultaneous patching

When you initiate a patch job, the service uses the instance filter you provided to determine the specific instances to be patched. Instance filters allow you to simultaneously patch many instances at the same time. This filtering is done when the patch job starts to account for changes in your environment after the job is scheduled.

Scheduled patching

Patches can be executed on demand, scheduled in advance, or configured with a recurring schedule. You can also cancel an in-progress patch job if you need to stop it immediately.

You can set up patch maintenance windows by creating patch deployments with a specified frequency and duration. Scheduling patch jobs with a specified duration ensures that patching tasks do not start outside of your designated maintenance window.

You can also enforce patch installation deadlines by creating patch deployments to be completed at a specific time. If targeted VMs are not patched by this date, then the scheduled deployment starts installing patches on this date. If VMs are already patched no action is taken on those VMs, unless a pre or post patch script is specified or a reboot is required.

What is included in an OS patch job?

When a patch job runs on a VM, depending on the operating system, a combination of updates are applied. You can also choose to target specific updates, packages, or, for Window operating systems, specify the KB IDs that you want to update.


For Windows operating system, you can apply all or select from the following updates:

  • Definition updates
  • Driver updates
  • Feature pack updates
  • Security updates
  • Tool updates


For Red Hat Enterprise Linux and Centos operating systems, you can apply all or select from the following updates:

  • System updates
  • Security updates


For Debian and Ubuntu systems, you can apply all or select from the following updates:

  • Distribution updates
  • Package manager updates


For SUSE Enterprise Linux Server (SLES) and openSUSE operating systems, you can apply all or select from the following updates:

  • System package updates
  • Zypper patches (specific bug fixes and security fixes)

The OS patch management dashboard

In the Google Cloud Console, a dashboard is available that you can use to monitor the patch compliance for your VM instances.

Go to the OS Patch Management page

OS patch management dashboard.

Understanding the OS patch management dashboard

Operating system overview

This section reflects the total number of VMs, organized by operating system. For a VM to show up in this list, it must have the OS Config agent installed and OS inventory management enabled.

Number of VMs card.

If a VM is listed with its operating system as No data, one or more of the following scenarios might be true:

  • The VM is unresponsive.
  • OS Config agent is not installed.
  • OS inventory management is not enabled.
  • The operating system is not supported. For a list of supported operating systems, see Supported operating systems.

Patch compliance status

OS specific card.

This section provides details of the compliance status of each of the VMs organized by their operating system.

Compliance status are arranged in four main categories:

  • Critical: This means that a VM has critical updates available.
  • Important or security: This means that a VM has important or security updates available.
  • Other: This means that a VM has updates available, but none of these updates are categorized as a critical or security update.
  • Up-to-date: This means that a VM has no updates available.

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