public interface ShardsAllocator
A ShardsAllocator
is the main entry point for shard allocation on nodes in the cluster.
The allocator makes basic decision where a shard instance will be allocated, if already allocated instances
need to relocate to other nodes due to node failures or due to rebalancing decisions.
Modifier and Type | Method and Description |
---|---|
void |
allocate(RoutingAllocation allocation)
Allocates shards to nodes in the cluster.
|
ShardAllocationDecision |
decideShardAllocation(ShardRouting shard,
RoutingAllocation allocation)
Returns the decision for where a shard should reside in the cluster.
|
void allocate(RoutingAllocation allocation)
allocation
- current node allocationShardAllocationDecision decideShardAllocation(ShardRouting shard, RoutingAllocation allocation)
AllocateUnassignedDecision
will be non-null. If the shard is not in the unassigned
state, then the MoveDecision
will be non-null.
This method is primarily used by the cluster allocation explain API to provide detailed explanations
for the allocation of a single shard. Implementations of the allocate(RoutingAllocation)
method
may use the results of this method implementation to decide on allocating shards in the routing table
to the cluster.
If an implementation of this interface does not support explaining decisions for a single shard through
the cluster explain API, then this method should throw a UnsupportedOperationException
.