Class AwarenessAllocationDecider
- java.lang.Object
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- org.elasticsearch.cluster.routing.allocation.decider.AllocationDecider
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- org.elasticsearch.cluster.routing.allocation.decider.AwarenessAllocationDecider
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public class AwarenessAllocationDecider extends AllocationDecider
ThisAllocationDecider
controls shard allocation based onawareness
key-value pairs defined in the node configuration. Awareness explicitly controls where replicas should be allocated based on attributes like node or physical rack locations. Awareness attributes accept arbitrary configuration keys like a rack data-center identifier. For example the setting:cluster.routing.allocation.awareness.attributes: rack_id
will cause allocations to be distributed over different racks such that ideally at least one replicas of the all shard is available on the same rack. To enable allocation awareness in this example nodes should contain a value for the
rack_id
key like:node.attr.rack_id:1
Awareness can also be used to prevent over-allocation in the case of node or even "zone" failure. For example in cloud-computing infrastructures like Amazon AWS a cluster might span over multiple "zones". Awareness can be used to distribute replicas to individual zones by setting:
cluster.routing.allocation.awareness.attributes: zone
and forcing allocation to be aware of the following zone the data resides in:
cluster.routing.allocation.awareness.force.zone.values: zone1,zone2
In contrast to regular awareness this setting will prevent over-allocation on
zone1
even ifzone2
fails partially or becomes entirely unavailable. Nodes that belong to a certain zone / group should be started with the zone id configured on the node-level settings like:node.zone: zone1
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Field Summary
Fields Modifier and Type Field Description static Setting<java.util.List<java.lang.String>>
CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING
static Setting<Settings>
CLUSTER_ROUTING_ALLOCATION_AWARENESS_FORCE_GROUP_SETTING
static java.lang.String
NAME
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Constructor Summary
Constructors Constructor Description AwarenessAllocationDecider(Settings settings, ClusterSettings clusterSettings)
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description Decision
canAllocate(ShardRouting shardRouting, RoutingNode node, RoutingAllocation allocation)
Returns aDecision
whether the given shard routing can be allocated on the given node.Decision
canRemain(ShardRouting shardRouting, RoutingNode node, RoutingAllocation allocation)
Returns aDecision
whether the given shard routing can be remain on the given node.-
Methods inherited from class org.elasticsearch.cluster.routing.allocation.decider.AllocationDecider
canAllocate, canAllocate, canAllocate, canForceAllocatePrimary, canRebalance, canRebalance
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Field Detail
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NAME
public static final java.lang.String NAME
- See Also:
- Constant Field Values
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CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING
public static final Setting<java.util.List<java.lang.String>> CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING
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Constructor Detail
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AwarenessAllocationDecider
public AwarenessAllocationDecider(Settings settings, ClusterSettings clusterSettings)
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Method Detail
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canAllocate
public Decision canAllocate(ShardRouting shardRouting, RoutingNode node, RoutingAllocation allocation)
Description copied from class:AllocationDecider
Returns aDecision
whether the given shard routing can be allocated on the given node. The default isDecision.ALWAYS
.- Overrides:
canAllocate
in classAllocationDecider
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canRemain
public Decision canRemain(ShardRouting shardRouting, RoutingNode node, RoutingAllocation allocation)
Description copied from class:AllocationDecider
Returns aDecision
whether the given shard routing can be remain on the given node. The default isDecision.ALWAYS
.- Overrides:
canRemain
in classAllocationDecider
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