# Glossary This glossary is a dictionary of terms defined as they are used by the spire/helm-charts project. Writing the definitions of terms here helps to keep other documents concise and precise. Documenting terminology here helps prevent misundersandings, facilitating easy onboarding of new team members. **Deployment** : A use of the Helm Charts to describe a single SPIRE cluster. **Deployment Type** : One of three supported deployments of the charts: Standalone, Primary, or Secondary. **Federation** : When one cluster is configured to trust elements of another cluster containing a different trust domain. **Federated Deployment** : A Primary Deployment or Standalone Deployment that is configured to federate with one or more Deployments. **Primary Deployment** : A deployment of the Helm Charts where the cluster's purpose is to provide certificates to Secondary Deployments. **Secondary Deployment** : A deployment of the Helm Charts where the cluster obtains an intermediate CA from a Primary Deployment and uses it to service Workload Identity requests. **Standalone Deployment** : A deployment of the Helm Charts where the cluster both manages the CA and services Workload Identity requests in the same cluster. **Tiered Deployment** : Use of the Helm Charts two or more times, such that one chart is configured as a Primary Deployment Type and the others are configured as Secondary Deployment Types. **Trust Domain** : The host field of a SPIFFE ID, naming a minimum footprint of a trust bundle's distribution.