constellation/docs/versioned_docs/version-2.2/workflows/verify-cluster.md

Verify your cluster

Constellation's attestation feature allows you, or a third party, to verify the integrity and confidentiality of your Constellation cluster.

Fetch measurements

To verify the integrity of Constellation you need trusted measurements to verify against. For each node image released by Edgeless Systems, there are signed measurements, which you can download using the CLI:

constellation config fetch-measurements

This command performs the following steps:

1. Download the signed measurements for the configured image. By default, this will use Edgeless Systems' public measurement registry.
2. Verify the signature of the measurements. This will use Edgeless Systems' public key.
3. Write measurements into configuration file.

After the command succeeded the configuration file will contain a list of key value pairs (index, hash) under the measurements key and a list of indices under enforcedMeasurements. Not all keys under measurements will have a matching index under enforcedMeasurements. This is because only a subset of the available measurements can be locally reproduced and verified. These non-reproducible values typically measure parts of the boot process that are controlled by the CSP. You can find a list with descriptions in the runtime measurements section.

During attestation, the validating side (CLI or join service) will compare each measurement reported by the issuing side (first node or joining node) individually. For mismatching measurements that are set under the measurements key a warning will be emitted. For mismatching measurements that are additionally set under enforcedMeasurements an error will be emitted and attestation fails. If attestation fails, the new node can't join the cluster.

The verify command

:::note The steps below are purely optional. They're automatically executed by constellation init when you initialize your cluster. The constellation verify command mostly has an illustrative purpose. :::

The verify command obtains and verifies an attestation statement from a running Constellation cluster.

constellation verify [--cluster-id ...]

From the attestation statement, the command verifies the following properties:

• The cluster is using the correct Confidential VM (CVM) type.
• Inside the CVMs, the correct node images are running. The node images are identified through the measurements obtained in the previous step.
• The unique ID of the cluster matches the one from your constellation-id.json file or passed in via --cluster-id.

Once the above properties are verified, you know that you are talking to the right Constellation cluster and it's in a good and trustworthy shape.

Custom arguments

The verify command also allows you to verify any Constellation deployment that you have network access to. For this you need the following:

• The IP address of a running Constellation cluster's VerificationService. The VerificationService is exposed via a NodePort service using the external IP address of your cluster. Run kubectl get nodes -o wide and look for EXTERNAL-IP.
• The cluster's clusterID. See cluster identity for more details.

For example:

constellation verify -e 192.0.2.1 --cluster-id Q29uc3RlbGxhdGlvbkRvY3VtZW50YXRpb25TZWNyZXQ=