Managing guest policies (legacy)

After you create a guest policy, you can use the following procedures to review and manage your policies:

Update guest policies: modify your guest policy configurations.
Describe guest policies: get details about a specific guest policy.
List guest policies: view a list of guest policies in a project.
Delete a guest: delete a specific guest policy.
View configurations for a VM instance: view configurations that are applied to a VM instance.
Debug a guest policy: troubleshoot a guest policy.

Since the OS Config agent runs every 10-15 minutes, when you set up a update or deletion of a policy it will take roughly 10-15 minutes to take effect.

You can manage your guest policies using either the Google Cloud CLI or REST.

Before you begin

Review OS Config quotas.
If you haven't already, then set up authentication. Authentication is the process by which your identity is verified for access to Google Cloud services and APIs. To run code or samples from a local development environment, you can authenticate to Compute Engine by selecting one of the following options:

Select the tab for how you plan to use the samples on this page:
gcloud
1. Install the Google Cloud CLI, then initialize it by running the following command:
```
gcloud init
```
  Note: If you installed the gcloud CLI previously, make sure you have the latest version by running gcloud components update.
2. Set a default region and zone.
REST

To use the REST API samples on this page in a local development environment, you use the credentials you provide to the gcloud CLI.
For more information, see Authenticate for using REST in the Google Cloud authentication documentation.

Updating guest policies

To update a guest policy, complete the following steps:

Update the YAML or JSON file.
Run an update or patch command. The update process is similar to the create process with the addition of support for etags that allow for concurrency and consistency control.

gcloud

Use the os-config guest-policies update command to update a guest policy.

gcloud beta compute os-config guest-policies update POLICY_ID \
     --file=FILE

Replace the following:

POLICY_ID: the name of the guest policy that you want to update.
FILE: the JSON or YAML file that contains the updated guest policy specifications.

REST

In the API, create a PATCH request to the projects.guestPolicies.patch method.

PATCH https://osconfig.googleapis.com/v1beta/projects/PROJECT_ID/guestPolicies/POLICY_ID

{
  For more information, see Guest policy JSON
}

Replace the following:

PROJECT_ID: your project ID.
POLICY_ID: the name of your guest policy.

Describing a guest policy

gcloud

To view details about a guest policy, use the os-config guest-policies describe command. Replace POLICY_ID with the name of the guest policy that you want to describe.

gcloud beta compute os-config guest-policies describe POLICY_ID

REST

In the API, create a GET request to the projects.guestPolicies.get method.

GET https://osconfig.googleapis.com/v1beta/projects/PROJECT_ID/guestPolicies/POLICY_ID

Replace the following:

PROJECT_ID: your project ID.
POLICY_ID: the name of your guest policy.

List guest policies

gcloud

To view a list of guest policies in your project, use the os-config guest-policies list command.

gcloud beta compute os-config guest-policies list

REST

In the API, create a GET request to the projects.guestPolicies.list method. Replace PROJECT_ID with your project ID.

GET https://osconfig.googleapis.com/v1beta/projects/PROJECT_ID/guestPolicies

Deleting guest policies

When the OS Config agent detects that a deletion of a guest policy is triggered, the current state of the system is maintained, but no further maintenance of the configuration is done. For example, say you have a guest policy package-update-zone2b set up that installs a package my-package on all VMs in zone us-west2-b and keeps the package UPDATED.

If you delete the package-update-zone2b policy, the following changes take place:

All VMs in us-west2-b that have my-package installed, keeps my-package installed. There is no reversion of the current system state.
On all future runs of the OS Config agent, after the policy deletion, the following takes place:
- If a new VM is added to us-west2-b,my-package is not installed on this new VM.
- For instances with my-package installed, the package is not updated.

gcloud

To delete a guest policy, use the os-config guest-policies delete command. Replace POLICY_ID with the name of the guest policy that you want to delete.

gcloud beta compute os-config guest-policies delete POLICY_ID

REST

In the API, create a DELETE request to the projects.guestPolicies.delete method.

DELETE https://osconfig.googleapis.com/v1beta/projects/PROJECT_ID/guestPolicies/POLICY_ID

Replace the following:

PROJECT_ID: your project ID.
POLICY_ID: the name of your guest policy.

View configurations for a VM instance

gcloud

To see the policies that are applied to a single VM instance, use the os-config guest-policies lookup command.

gcloud beta compute os-config guest-policies lookup VM_NAME \
    --zone=ZONE

Replace the following:

VM_NAME: the name of the VM instance.
ZONE: the zone for the VM instance.

REST

To see the policies that are applied to a single VM instance, use the following POST request.

POST https://osconfig.googleapis.com/v1beta/projects/PROJECT_ID/zones/ZONE/instances/VM_NAME:lookupEffectiveGuestPolicy

Replace the following:

PROJECT_ID: your project ID.
ZONE: the zone for the VM instance.
VM_NAME: the name of your VM instance.

Troubleshooting

Inspect guest policies

You can use the Google Cloud console or Google Cloud CLI to inspect the guest policies associated with your project.

Console

In the Google Cloud console, go to the OS Guest Policies page.

Go to the OS Guest Policies page
Select the guest policy that you want to inspect, and then click VIEW DETAILS.

gcloud

Use the os-config guest-policies list command to list all your guest policies.
```
gcloud beta compute os-config guest-policies list
```
From the list of guest policies, copy the IDs of the guest policies you would like to inspect, and then run the command to inspect each of the guest policies. Replace POLICY_ID with the policy ID that you want to review.
```
gcloud beta compute os-config guest-policies describe POLICY_ID
```

Inspect guest policies for a specific VM

You can run the lookup command for a given VM to see which configurations apply to that VM.

In cases where a VM does not seem to be applying the requirements of the expected guest policy, it is useful to inspect the list of guest policies whose assignments include that specific VM instance. This helps to determine if the Assignment field in the guest policy matches this particular VM.

Use the os-config guest-policies lookup command to list the guest policies that might be targeting a particular VM. Replace VM_NAME with the name of the VM to inspect.

gcloud beta compute os-config guest-policies lookup VM_NAME

For more information, see Viewing configurations for a VM instance.

The output from the command might reveal that the VM is not actually targeted in the VM assignment properties of the guest policy. For example, it might not be listed in the list of Labels or the list of VM name prefixes.

Recovering from failure

A failed software recipe installation is not retried. This is because the system doesn't know the state in which the failed software recipe left things.

When debugging failed software recipes, we recommend the following steps:

Rename the software recipe.
Delete and recreate the guest policy using the renamed software recipe.

For more troubleshooting steps, see Troubleshooting VM Manager.

What's next?

Learn more about the OS guest policies (legacy).
Set up a guest policy.