Module Nn_monitor

module Nn_monitor: sig .. end

Management of datastores, i.e. which datastores are available on which datanodes

This module is run inside the single nn_monitor process. Read access from other processes is possible via the Nn_datastore_news module (using a pub/sub scheme).

The module can also be notified to merge db changes into its in-core set of datastores.

val list : unit -> Nn_datastores.datastore list

Returns the list of all datastores

val get : string -> Nn_datastores.datastore

Get the store record by identity string, or raise Not_found

val add : Nn_datastores.datastore -> unit

Add the datastore record as-is (for initializing this module from db).

val update_from_db : ?when_done:(unit -> unit) -> int -> unit

Read the db version of this record, and trigger the update of the module copy of it. The actual update will happen at some point in the future.

val delete : string -> unit

delete identity: Remove this store

val enable : string -> unit

enable identity: Sets enabled to true

val disable : string -> unit

disable identity: Sets enabled to false

val is_alive : string -> bool

is_alive identity: Returns whether the datanode having this store is good as seen by the monitor. Fails if the monitor is not started.

val start_publishing : unit -> unit

Updates on the datastores are published and can be retrieved from any other process using Nn_datastore_news

Stops feeding the news module

val post_add_hook : Netplex_types.socket_service -> Netplex_types.controller -> unit

Needs to be called from the post_add_hook

val receive_message : Pfs_auth.client_auth ->
       Netplex_types.container -> string -> string array -> unit

Needs to be called from the receive_message hook in order to arrange notifications about db updates

val post_start_hook : Netplex_types.container ->
       Nn_config.nn_node_config -> Pfs_auth.client_auth -> unit

Reads the datastore table from the database, and starts discovering datanodes.

It is required that Nn_db.init was called before.

val shutdown : unit -> unit

To be called at shutdown time

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