trait ShardAllocationStrategy extends NoSerializationVerificationNeeded

Interface of the pluggable shard allocation and rebalancing logic used by the ShardCoordinator.

Java implementations should extend AbstractShardAllocationStrategy.

Source
ShardCoordinator.scala
Linear Supertypes
NoSerializationVerificationNeeded, AnyRef, Any
Known Subclasses
AbstractShardAllocationStrategy, StartableAllocationStrategy, ExternalShardAllocationStrategy
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Inherited
  1. ShardAllocationStrategy
  2. NoSerializationVerificationNeeded
  3. AnyRef
  4. Any
Implicitly
  1. by any2stringadd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
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Visibility
  1. Public
  2. Protected

Abstract Value Members

  1. abstract def allocateShard(requester: ActorRef, shardId: ShardId, currentShardAllocations: Map[, [ShardId]]): [ActorRef]

    Invoked when the location of a new shard is to be decided.

    Invoked when the location of a new shard is to be decided.

    requester

    actor reference to the ShardRegion that requested the location of the shard, can be returned if preference should be given to the node where the shard was first accessed

    shardId

    the id of the shard to allocate

    currentShardAllocations

    all actor refs to ShardRegion and their current allocated shards, in the order they were allocated

    returns

    a Future of the actor ref of the ShardRegion that is to be responsible for the shard, must be one of the references included in the currentShardAllocations parameter

  2. abstract def rebalance(currentShardAllocations: Map[, [ShardId]], rebalanceInProgress: Set[ShardId]): Future[Set[ShardId]]

    Invoked periodically to decide which shards to rebalance to another location.

    Invoked periodically to decide which shards to rebalance to another location.

    currentShardAllocations

    all actor refs to ShardRegion and their current allocated shards, in the order they were allocated

    rebalanceInProgress

    set of shards that are currently being rebalanced, i.e. you should not include these in the returned set

    returns

    a Future of the shards to be migrated, may be empty to skip rebalance in this round