org.elasticsearch.cluster.routing.allocation.decider.ConcurrentRebalanceAllocationDecider Maven / Gradle / Ivy
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package org.elasticsearch.cluster.routing.allocation.decider;
import org.elasticsearch.cluster.routing.ShardRouting;
import org.elasticsearch.cluster.routing.allocation.RoutingAllocation;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.node.settings.NodeSettingsService;
/**
* Similar to the {@link ClusterRebalanceAllocationDecider} this
* {@link AllocationDecider} controls the number of currently in-progress
* re-balance (relocation) operations and restricts node allocations if the
* configured threashold is reached. The default number of concurrent rebalance
* operations is set to 2
*
* Re-balance operations can be controlled in real-time via the cluster update API using
* cluster.routing.allocation.cluster_concurrent_rebalance. Iff this
* setting is set to -1 the number of concurrent re-balance operations
* are unlimited.
*/
public class ConcurrentRebalanceAllocationDecider extends AllocationDecider {
public static final String NAME = "concurrent_rebalance";
public static final String CLUSTER_ROUTING_ALLOCATION_CLUSTER_CONCURRENT_REBALANCE = "cluster.routing.allocation.cluster_concurrent_rebalance";
class ApplySettings implements NodeSettingsService.Listener {
@Override
public void onRefreshSettings(Settings settings) {
int clusterConcurrentRebalance = settings.getAsInt(CLUSTER_ROUTING_ALLOCATION_CLUSTER_CONCURRENT_REBALANCE, ConcurrentRebalanceAllocationDecider.this.clusterConcurrentRebalance);
if (clusterConcurrentRebalance != ConcurrentRebalanceAllocationDecider.this.clusterConcurrentRebalance) {
logger.info("updating [cluster.routing.allocation.cluster_concurrent_rebalance] from [{}], to [{}]", ConcurrentRebalanceAllocationDecider.this.clusterConcurrentRebalance, clusterConcurrentRebalance);
ConcurrentRebalanceAllocationDecider.this.clusterConcurrentRebalance = clusterConcurrentRebalance;
}
}
}
private volatile int clusterConcurrentRebalance;
@Inject
public ConcurrentRebalanceAllocationDecider(Settings settings, NodeSettingsService nodeSettingsService) {
super(settings);
this.clusterConcurrentRebalance = settings.getAsInt(CLUSTER_ROUTING_ALLOCATION_CLUSTER_CONCURRENT_REBALANCE, 2);
logger.debug("using [cluster_concurrent_rebalance] with [{}]", clusterConcurrentRebalance);
nodeSettingsService.addListener(new ApplySettings());
}
@Override
public Decision canRebalance(ShardRouting shardRouting, RoutingAllocation allocation) {
if (clusterConcurrentRebalance == -1) {
return allocation.decision(Decision.YES, NAME, "all concurrent rebalances are allowed");
}
if (allocation.routingNodes().getRelocatingShardCount() >= clusterConcurrentRebalance) {
return allocation.decision(Decision.NO, NAME, "too man concurrent rebalances [%d], limit: [%d]",
allocation.routingNodes().getRelocatingShardCount(), clusterConcurrentRebalance);
}
return allocation.decision(Decision.YES, NAME, "below threshold [%d] for concurrent rebalances", clusterConcurrentRebalance);
}
}