Using Shielded GKE Nodes

This page shows you how to use the Shielded GKE Nodes feature. Shielded GKE Nodes provide strong, verifiable node identity and integrity to increase the security of GKE nodes.

About Shielded GKE Nodes

Shielded GKE Nodes are built on top of Compute Engine Shielded VMs. Without Shielded GKE Nodes an attacker can exploit a vulnerability in a Pod to exfiltrate bootstrap credentials and impersonate nodes in your cluster, giving the attackers access to cluster secrets. When Shielded GKE Nodes is enabled, the GKE control plane cryptographically verifies that:

• Every node in your cluster is a virtual machine running in Google's data center.
• Every node is part of the managed instance group provisioned for the cluster.
• The kubelet is being provisioned a certificate for the node on which it is running.

This limits the ability of an attacker to impersonate a node in your cluster even if they are able to exfiltrate bootstrap credentials of the node.

You can optionally configure node integrity checks on node pools to provide enhanced rootkit and bootkit protection for your nodes. These node pool settings are independent from Shielded GKE Nodes and will work even if Shielded GKE Nodes is disabled on the cluster.

For more information, see the Shielded VM documentation.

There is no additional cost to run Shielded GKE Nodes. However, Shielded GKE Nodes generate about 0.5 KB more logs on startup than standard nodes. See the Cloud Logging pricing page for details.

Availability

Important: Starting with GKE 1.18, newly created clusters will have Shielded GKE Nodes enabled by default.

• Shielded GKE Nodes are available in GKE 1.13.6-gke.0 and higher.
• Shielded GKE Nodes are available in all zones and regions.
• Shielded GKE Nodes can be used with Container-Optimized OS (COS), COS with containerd, and Ubuntu node images.
• Shielded GKE Nodes can be used with GPUs.

Warning: After you enable Shielded GKE Nodes in a cluster, any nodes created in a node pool without Shielded GKE Nodes enabled or created outside of any node pool aren't able to join the cluster.

Before you begin

Before you start, make sure you have performed the following tasks:

• Ensure that you have enabled the Google Kubernetes Engine API.
Enable Google Kubernetes Engine API
• Ensure that you have installed the Cloud SDK.

Set up default gcloud settings using one of the following methods:

• Using gcloud init, if you want to be walked through setting defaults.
• Using gcloud config, to individually set your project ID, zone, and region.

Using gcloud init

If you receive the error One of [--zone, --region] must be supplied: Please specify location, complete this section.

1. Run gcloud init and follow the directions:

   gcloud init

   If you are using SSH on a remote server, use the --console-only flag to prevent the command from launching a browser:

   gcloud init --console-only

2. Follow the instructions to authorize gcloud to use your Google Cloud account.
3. Create a new configuration or select an existing one.
4. Choose a Google Cloud project.
5. Choose a default Compute Engine zone.

Note: You can override these default settings in gcloud commands using the --project, --zone, and --region flags.

Using gcloud config

• Set your default project ID:

  gcloud config set project PROJECT_ID

• If you are working with zonal clusters, set your default compute zone:

  gcloud config set compute/zone COMPUTE_ZONE

• If you are working with regional clusters, set your default compute region:

  gcloud config set compute/region COMPUTE_REGION

• Update gcloud to the latest version:

  gcloud components update

Note: You can override these default settings in gcloud commands using the --project, --zone, and --region flags.

Enabling Shielded GKE Nodes in a new cluster

You can create a new cluster with Shielded GKE Nodes enabled by using gcloud tool or Google Cloud Console.

gcloud

When creating a new cluster, specify the --enable-shielded-nodes option:

gcloud container clusters create cluster-name --enable-shielded-nodes

Console

1. Visit the Google Kubernetes Engine menu in Cloud Console.

   Visit the Google Kubernetes Engine menu

2. Click Create.

3. From the navigation pane, under Cluster, click Security.

4. Select the Enable Shielded GKE Nodes checkbox.

5. Configure your cluster as desired.

6. Click Create.

See Creating a cluster for more details about creating clusters.

Enabling Shielded GKE Nodes in an existing cluster

You can enable Shielded GKE Nodes in an existing cluster by using the gcloud command-line tool or Google Cloud Console.

After you enable Shielded GKE Nodes, the control plane and nodes are recreated as Shielded VMs. The control plane is unavailable while it is being recreated. The cluster nodes are recreated in a rolling fashion to minimize downtime.

Warning: If you are using maintenance windows, your control plane and nodes are not recreated until a maintenance window occurs. This delay might cause failed node registrations and disruption to your cluster. To minimize disruption, you can manually "upgrade" the node pool to the same version that it is already using, by setting the --cluster-version flag to the same GKE version that the control plane is already running. You must use the gcloud command if you use this workaround. For more information, see the caveats section of the maintenance window documentation.

gcloud

When updating the cluster, specify the --enable-shielded-nodes option:

gcloud container clusters update cluster-name --enable-shielded-nodes

console

1. Visit the Google Kubernetes Engine menu in Cloud Console.

   Visit the Google Kubernetes Engine menu

2. Click the cluster's Edit button, which looks like a pencil.

3. In the Shielded GKE Nodes drop-down list, select Enabled.

Verifying that Shielded GKE Nodes are enabled

You verify that your cluster is using Shielded GKE Nodes with the gcloud command-line tool or Google Cloud Console.

gcloud

Describe the cluster:

gcloud container clusters describe cluster-name

If Shielded GKE Nodes are enabled, the output of the command will include these lines:

shieldedNodes:
  enabled: true

Console

1. Navigate to the cluster details tab by clicking the cluster's name in the list of your clusters in your project.
2. In the details list, verify that Shielded GKE Nodes is enabled.

You can also monitor the integrity of your nodes' underlying Shielded VMs. See Monitoring Integrity on Shielded VM Instances for the procedure.

Disabling Shielded GKE Nodes

You can disable Shielded GKE Nodes with the gcloud command-line tool or Google Cloud Console.

Warning: If you are using maintenance windows, your control plane and nodes are not recreated until a maintenance window occurs. This delay might cause failed node registrations and disruption to your cluster. To minimize disruption, you can manually "upgrade" the node pool to the same version that it is already using, by setting the --cluster-version flag to the same GKE version that the control plane is already running. You must use the gcloud command if you use this workaround. For more information, see the caveats section of the maintenance window documentation.

gcloud

When updating the cluster, specify the --no-enable-shielded-nodes option:

gcloud container clusters update cluster-name --no-enable-shielded-nodes

Console

1. Visit the Google Kubernetes Engine menu in Cloud Console.

   Visit the Google Kubernetes Engine menu

2. Click the cluster's Edit button, which looks like a pencil.

3. In the Shielded GKE Nodes drop-down list, select Disabled.

After you disable Shielded GKE Nodes, the control plane and nodes are recreated as ordinary, unshielded VMs. The control plane is unavailable while it is being recreated. The cluster nodes are recreated in a rolling fashion to minimize downtime.

Node integrity

Secure Boot and Integrity Monitoring are node pool settings that can be used alongside Shielded GKE Nodes. Shielded GKE Nodes, Secure Boot, and Integrity Monitoring are independent features that can each be enabled or disabled individually.

Secure boot

Secure boot is a node pool setting that's disabled by default on GKE because third-party unsigned kernel modules cannot be loaded when secure boot is enabled.

If you don't use third-party unsigned kernel modules, you can enable secure boot with the gcloud command-line tool or Google Cloud Console.

gcloud

To enable secure boot when creating a cluster:

gcloud container cluster create cluster-name --shielded-secure-boot

To enable secure boot when creating a node pool:

gcloud container node-pool create pool-name --shielded-secure-boot

Secure boot is disabled by default. You can explicitly disable it when creating a cluster or node pool with the --no-shielded-secure-boot option.

Console

To enable secure boot when creating a node pool:

1. Navigate to the cluster details page.
2. At the top of the page, click Add Node Pool.
3. In the Shielded options section, select the Secure boot checkbox.

Integrity monitoring

Integrity monitoring is a node pool setting that's enabled by default on GKE. You can disable integrity monitoring with the gcloud command-line tool or Google Cloud Console.

gcloud

To disable integrity monitoring for system components when creating a cluster:

gcloud container cluster create cluster-name --no-shielded-integrity-monitoring

To disable integrity monitoring for system components when creating a node pool:

gcloud container node-pool create pool-name --no-shielded-integrity-monitoring

Integrity monitoring is enabled by default. You can explicitly enable it when creating a cluster or node pool with the --shielded-integrity-monitoring option.

Console

To disable integrity monitoring when creating a node pool:

1. Navigate to the cluster details page.
2. At the top of the page, click Add Node Pool.
3. In the Shielded options section, clear the Integrity monitoring checkbox.

What's next

• Learn more about Shielded VM
• Learn more about node images.