## Uses of Class
org.apache.hadoop.hdfs.server.federation.router.PeriodicService

- Packages that use PeriodicService
  Package | Description
  --- | ---
  org.apache.hadoop.hdfs.server.federation.router | The router package includes the core services for a HDFS federation router.
  org.apache.hadoop.hdfs.server.federation.store | The federation state store tracks persistent values that are shared between multiple routers.

- - ### Uses of PeriodicService in org.apache.hadoop.hdfs.server.federation.router

    Subclasses of PeriodicService in org.apache.hadoop.hdfs.server.federation.router with annotations of type with type parameters of type that implement declared as with annotations of type with type parameters of type with annotations of type with annotations of type with type parameters of type that return that return types with arguments of type with parameters of type with type arguments of type that throw with annotations of type with annotations of type with parameters of type with type arguments of type that throw
    Modifier and Type | Class and Description
    --- | ---
    `class` | `NamenodeHeartbeatService` The `Router` periodically checks the state of a Namenode (usually on the same server) and reports their high availability (HA) state and load/space status to the `StateStoreService` .
    `class` | `RouterHeartbeatService` Service to periodically update the Router current state in the State Store.
    `class` | `RouterQuotaUpdateService` Service to periodically update the `RouterQuotaUsage` cached information in the `Router` and update corresponding mount table in State Store.
    `class` | `RouterSafemodeService` Service to periodically check if the {@link org.apache.hadoop.hdfs.server.

  - ### Uses of PeriodicService in org.apache.hadoop.hdfs.server.federation.store

    Subclasses of PeriodicService in org.apache.hadoop.hdfs.server.federation.store with annotations of type with type parameters of type that implement declared as with annotations of type with type parameters of type with annotations of type with annotations of type with type parameters of type that return that return types with arguments of type with parameters of type with type arguments of type that throw with annotations of type with annotations of type with parameters of type with type arguments of type that throw
    Modifier and Type | Class and Description
    --- | ---
    `class` | `StateStoreCacheUpdateService` Service to periodically update the `StateStoreService` cached information in the `Router`.
    `class` | `StateStoreConnectionMonitorService` Service to periodically monitor the connection of the StateStore `StateStoreService` data store and to re-open the connection to the data store if required.

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