Agent Attestation Methods

Agent attestation methods are the mechanisms by which the Trust Domain Server verifies the identity of an agent at login time. The server issues a session to the agent only if the agent satisfies the configured attestation requirements.

Policies

Agent attestation is configured via policies. Each policy contains one or more required attestors that must all pass. Multiple policies can be defined for a single cluster; an agent is authorized if it satisfies any one policy.

This gives you two composition patterns:

AND (all required within a policy) — agent must pass both Kubernetes PSAT and AWS identity:

section: AgentAttestation
schema: v1
spec:
  policies:
    - name: eks_cluster_policy
      requiredAttestors:
        - type: k8s_token
          config:
            issuerURL: https://oidc.eks.us-east-1.amazonaws.com/id/ABCDEF123456
        - type: aws_iid

OR (multiple policies) — agent can authenticate via Kubernetes PSAT or SSH:

section: AgentAttestation
schema: v1
spec:
  policies:
    - name: k8s_policy
      requiredAttestors:
        - type: k8s_token
          config:
            issuerURL: https://oidc.eks.us-east-1.amazonaws.com/id/ABCDEF123456
    - name: ssh_policy
      requiredAttestors:
        - type: ssh_pop
          config:
            certAuthorities:
              - "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAA..."

Applying Configuration

Agent attestation policies are applied per-cluster using Managed Configuration.

Using spirlctl

spirlctl config set cluster --id <cluster-id> attestation-policy.yaml

Using Terraform

resource "spirl_cluster_config" "agent_attestation" {
  cluster_id = spirl_cluster.my_cluster.id
  sections = {
    AgentAttestation = <<-YAML
      section: AgentAttestation
      schema: v1
      spec:
        policies:
          - name: eks_cluster_policy
            requiredAttestors:
              - type: k8s_token
                config:
                  issuerURL: https://oidc.eks.us-east-1.amazonaws.com/id/ABCDEF123456
    YAML
  }
}

Once a configuration document passes validation and is stored, the Defakto control plane syncs it to your Trust Domain Servers automatically. No server or agent restart is required.

Attributes available for SVID issuance

Most attestation methods produce attributes derived from the agent's verified identity. These attributes are available for use in:

Attributes from agent attestation are scoped to the agent session. They complement workload attributes, which are collected per SVID request.

Available Methods

Method	Type identifier	Attributes produced	Common use case
AWS Identity Document	`aws_iid`	EC2 instance metadata, tags, IAM role	AWS EC2 instances
AWS Web Identity Token	`aws_token`	Account, org, IAM tags	AWS workloads with IAM outbound federation
Azure IMDS	`azure_imds`	VM metadata, tags, VMSS, network	Azure VMs without Managed Identity
Azure MSI	`azure_msi`	Tenant ID, principal ID	Azure VMs with Managed Identity
Agent Attestation Extension	`extension`	Custom (webhook-defined)	Organization-specific agent verification via external webhook
GCP Instance Identity Token	`gcp_iit`	Project, instance, zone, labels	GCP Compute Engine VMs
HTTP DNS	`http_dns`	Hostname, port	Non-cloud VMs with DNS control
Kubernetes Service Account Token	`k8s_token`	Default Kubernetes attributes	K8s agents
SSH Proof of Possession	`ssh_pop`	Certificate principals, serial, validity	Hosts with SSH host certificates
TPM Endorsement Key	`tpm_ek`	Hardware fingerprint, manufacturer	Bare-metal, hardware-rooted trust
X.509 Proof of Possession	`x509pop`	Certificate identity, URI SANs	Pre-provisioned certs (PKI-heavy environments)

Policies​

Applying Configuration​

Using spirlctl​

Using Terraform​

Attributes available for SVID issuance​

Available Methods​