Glossary

Definitions

For every Kubernetes cluster that wants to be managed, we call it child cluster. The cluster where child clusters are registerring to, we call it parent cluster.

clusternet-agent runs in child cluster, while clusternet-scheduler and clusternet-hub runs in parent cluster.

CRDs

• ClusterRegistrationRequest is an object that clusternet-agent creates in parent cluster for child cluster registration.
• ManagedCluster is an object that clusternet-hub creates in parent cluster after approving ClusterRegistrationRequest.
• HelmChart is an object contains a helm chart configuration.
• Subscription defines the resources (we call them as a group of Feeds) that subscribers want to install into clusters. Various SchedulingStrategy are supported, such as Replication, StaticDividing and DynamicDividing. For every matched cluster, a corresponding Base object will be created in its dedicated namespace.
• Clusternet provides a two-stage priority based override strategy. Localization and Globalization will define the overrides with priority, where lower numbers are considered lower priority. Localization is namespace-scoped resource, while Globalization is cluster-scoped. Refer to tutorial on how to set overrides in Clusternet.
• Base objects will be rendered to Description objects with Globalization and Localization settings applied. Description is the final resources to be deployed into target child clusters.
• FeedInventory objects are used to track and record the scheduling requirements (such as replicas, node selectors, tolerations, affinity rules, resource requirements, etc.) for each feed in the Subscription object of the same name. This FeedInventory object is only applicable when SchedulingStrategy is set to DynamicDividing. For other scheduling strategies, FeedInventory makes no sense.