allocation: create separate limit for frozen tier concurrent rebalance #135243
There are no files selected for viewing
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
|
|
@@ -20,13 +20,15 @@ | |
| /** | ||
| * Similar to the {@link ClusterRebalanceAllocationDecider} this | ||
| * {@link AllocationDecider} controls the number of currently in-progress | ||
| * re-balance (shard relocation) operations and restricts node allocations | ||
| * if the configured threshold is reached. Frozen and non-frozen shards are | ||
| * considered separately. The default number of concurrent rebalance operations | ||
| * is set to {@code 2} for non-frozen shards, and {@code 10} for frozen shards. | ||
| * <p> | ||
| * Re-balance operations can be controlled in real-time via the cluster update API using | ||
| * {@code cluster.routing.allocation.cluster_concurrent_rebalance} and | ||
| * {@code cluster.routing.allocation.cluster_concurrent_frozen_rebalance}. | ||
| * Iff either setting is set to {@code -1} the number of concurrent re-balance operations | ||
| * are unlimited. | ||
| */ | ||
| public class ConcurrentRebalanceAllocationDecider extends AllocationDecider { | ||
|
|
@@ -44,21 +46,89 @@ public class ConcurrentRebalanceAllocationDecider extends AllocationDecider { | |
| ); | ||
| private volatile int clusterConcurrentRebalance; | ||
|
|
||
| /** | ||
| * Same as cluster_concurrent_rebalance, but applies separately to frozen tier shards | ||
| */ | ||
| public static final Setting<Integer> CLUSTER_ROUTING_ALLOCATION_CLUSTER_CONCURRENT_FROZEN_REBALANCE_SETTING = Setting.intSetting( | ||
| "cluster.routing.allocation.cluster_concurrent_frozen_rebalance", | ||
| 10, | ||
| -1, | ||
| Property.Dynamic, | ||
| Property.NodeScope | ||
| ); | ||
| private volatile int clusterConcurrentFrozenRebalance; | ||
|
|
||
| public ConcurrentRebalanceAllocationDecider(ClusterSettings clusterSettings) { | ||
| clusterSettings.initializeAndWatch( | ||
| CLUSTER_ROUTING_ALLOCATION_CLUSTER_CONCURRENT_REBALANCE_SETTING, | ||
| this::setClusterConcurrentRebalance | ||
| ); | ||
| clusterSettings.initializeAndWatch( | ||
| CLUSTER_ROUTING_ALLOCATION_CLUSTER_CONCURRENT_FROZEN_REBALANCE_SETTING, | ||
| this::setClusterConcurrentFrozenRebalance | ||
| ); | ||
| logger.debug( | ||
| "using [cluster_concurrent_rebalance] with [concurrent_rebalance={}, concurrent_frozen_rebalance={}]", | ||
| clusterConcurrentRebalance, | ||
| clusterConcurrentFrozenRebalance | ||
| ); | ||
| } | ||
|
|
||
| private void setClusterConcurrentRebalance(int concurrentRebalance) { | ||
| clusterConcurrentRebalance = concurrentRebalance; | ||
| } | ||
|
|
||
| private void setClusterConcurrentFrozenRebalance(int concurrentFrozenRebalance) { | ||
| clusterConcurrentFrozenRebalance = concurrentFrozenRebalance; | ||
| } | ||
|
|
||
| @Override | ||
| public Decision canRebalance(ShardRouting shardRouting, RoutingAllocation allocation) { | ||
| int relocatingFrozenShards = allocation.routingNodes().getRelocatingFrozenShardCount(); | ||
nicktindall marked this conversation as resolved.
Show resolved
Hide resolved
|
||
| if (allocation.routingNodes().isDedicatedFrozenNode(shardRouting.currentNodeId())) { | ||
| if (clusterConcurrentFrozenRebalance == -1) { | ||
| return allocation.decision(Decision.YES, NAME, "unlimited concurrent frozen rebalances are allowed"); | ||
| } | ||
| if (relocatingFrozenShards >= clusterConcurrentFrozenRebalance) { | ||
| return allocation.decision( | ||
| Decision.THROTTLE, | ||
| NAME, | ||
| "reached the limit of concurrently rebalancing frozen shards [%d], cluster setting [%s=%d]", | ||
| relocatingFrozenShards, | ||
| CLUSTER_ROUTING_ALLOCATION_CLUSTER_CONCURRENT_FROZEN_REBALANCE_SETTING.getKey(), | ||
| clusterConcurrentFrozenRebalance | ||
| ); | ||
| } | ||
| return allocation.decision( | ||
| Decision.YES, | ||
| NAME, | ||
| "below threshold [%d] for concurrent frozen rebalances, current frozen rebalance shard count [%d]", | ||
| clusterConcurrentFrozenRebalance, | ||
| relocatingFrozenShards | ||
| ); | ||
| } else { | ||
| int relocatingShards = allocation.routingNodes().getRelocatingShardCount() - relocatingFrozenShards; | ||
| if (clusterConcurrentRebalance == -1) { | ||
| return allocation.decision(Decision.YES, NAME, "unlimited concurrent rebalances are allowed"); | ||
| } | ||
| if (relocatingShards >= clusterConcurrentRebalance) { | ||
| return allocation.decision( | ||
| Decision.THROTTLE, | ||
| NAME, | ||
| "reached the limit of concurrently rebalancing shards [%d], cluster setting [%s=%d]", | ||
| relocatingShards, | ||
| CLUSTER_ROUTING_ALLOCATION_CLUSTER_CONCURRENT_REBALANCE_SETTING.getKey(), | ||
| clusterConcurrentRebalance | ||
| ); | ||
| } | ||
| return allocation.decision( | ||
| Decision.YES, | ||
| NAME, | ||
| "below threshold [%d] for concurrent rebalances, current rebalance shard count [%d]", | ||
| clusterConcurrentRebalance, | ||
| relocatingShards | ||
| ); | ||
| } | ||
| } | ||
|
|
||
| /** | ||
|
|
@@ -68,33 +138,52 @@ public Decision canRebalance(ShardRouting shardRouting, RoutingAllocation alloca | |
| */ | ||
| @Override | ||
| public Decision canRebalance(RoutingAllocation allocation) { | ||
nicktindall marked this conversation as resolved.
Show resolved
Hide resolved
|
||
| int relocatingFrozenShards = allocation.routingNodes().getRelocatingFrozenShardCount(); | ||
| int relocatingShards = allocation.routingNodes().getRelocatingShardCount(); | ||
| if (allocation.isSimulating() && relocatingShards >= 2) { | ||
| // BalancedShardAllocator is prone to perform unnecessary moves when cluster_concurrent_rebalance is set to high values (>2). | ||
| // (See https://github.com/elastic/elasticsearch/issues/87279) | ||
| // Above allocator is used in DesiredBalanceComputer. Since we do not move actual shard data during calculation | ||
| // it is possible to artificially set above setting to 2 to avoid unnecessary moves in desired balance. | ||
| // Separately: keep overall limit in simulation to two including frozen shards | ||
| return allocation.decision(Decision.THROTTLE, NAME, "allocation should move one shard at the time when simulating"); | ||
|
There was a problem hiding this comment. As discussed, this whole branch might be redundant (?) since #134786 There was a problem hiding this comment. This is helpful -- can we leave this to a separate PR? This may not be the only decider that needs to change. |
||
| } | ||
|
|
||
| // separate into frozen/non-frozen counts | ||
| relocatingShards = relocatingShards - relocatingFrozenShards; | ||
|
|
||
| // either frozen or non-frozen having some allowance before their limit means the allocator has room to rebalance | ||
| if (clusterConcurrentRebalance == -1 || relocatingShards < clusterConcurrentRebalance) { | ||
| return allocation.decision( | ||
| Decision.YES, | ||
| NAME, | ||
| "below threshold [%d] for concurrent rebalances, current rebalance shard count [%d]", | ||
| relocatingShards, | ||
| CLUSTER_ROUTING_ALLOCATION_CLUSTER_CONCURRENT_REBALANCE_SETTING.getKey(), | ||
| clusterConcurrentRebalance | ||
|
||
| ); | ||
| } | ||
| if (clusterConcurrentFrozenRebalance == -1 || relocatingFrozenShards < clusterConcurrentFrozenRebalance) { | ||
| return allocation.decision( | ||
| Decision.YES, | ||
| NAME, | ||
| "below threshold [%d] for concurrent frozen rebalances, current frozen rebalance shard count [%d]", | ||
| relocatingFrozenShards, | ||
| CLUSTER_ROUTING_ALLOCATION_CLUSTER_CONCURRENT_FROZEN_REBALANCE_SETTING.getKey(), | ||
| clusterConcurrentFrozenRebalance | ||
| ); | ||
nicktindall marked this conversation as resolved.
Show resolved
Hide resolved
|
||
| } | ||
| return allocation.decision( | ||
| Decision.THROTTLE, | ||
| NAME, | ||
| "reached the limit of concurrently rebalancing shards [%d] for concurrent rebalances, cluster setting [%s=%d], " | ||
| + "and [%d] for concurrent frozen rebalances, frozen cluster setting [%s=%d]", | ||
| relocatingShards, | ||
| CLUSTER_ROUTING_ALLOCATION_CLUSTER_CONCURRENT_REBALANCE_SETTING.getKey(), | ||
| clusterConcurrentRebalance, | ||
| relocatingFrozenShards, | ||
| CLUSTER_ROUTING_ALLOCATION_CLUSTER_CONCURRENT_FROZEN_REBALANCE_SETTING.getKey(), | ||
| clusterConcurrentFrozenRebalance | ||
| ); | ||
| } | ||
| } | ||
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
This doc is out of date with the implementation.