Add link to Max Shards Per Node exception message

docs/changelog/110993.yaml

@@ -0,0 +1,5 @@
+pr: 110993
+summary:  Add link to Max Shards Per Node exception message
+area: Distributed
+type: enhancement
+issues: []

docs/reference/how-to/size-your-shards.asciidoc

@@ -501,6 +501,7 @@ POST _reindex
 Here’s how to resolve common shard-related errors.
 
 [discrete]
+[[troubleshooting-max-shards-open]]
 ==== this action would add [x] total shards, but this cluster currently has [y]/[z] maximum shards open;
 
 The <<cluster-max-shards-per-node,`cluster.max_shards_per_node`>> cluster

server/src/internalClusterTest/java/org/elasticsearch/cluster/shards/ClusterShardLimitIT.java

@@ -17,6 +17,7 @@
 import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.metadata.Metadata;
 import org.elasticsearch.common.Priority;
+import org.elasticsearch.common.ReferenceDocs;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.ByteSizeUnit;
 import org.elasticsearch.index.IndexVersion;
@@ -152,7 +153,9 @@ public void testIncreaseReplicasOverLimit() {
                 + firstShardCount
                 + "]/["
                 + dataNodes * shardsPerNode
-                + "] maximum normal shards open;";
+                + "] maximum normal shards open; for more information, see "
+                + ReferenceDocs.MAX_SHARDS_PER_NODE
+                + ";";
             assertEquals(expectedError, e.getMessage());
         }
         Metadata clusterState = clusterAdmin().prepareState().get().getState().metadata();
@@ -211,7 +214,9 @@ public void testChangingMultipleIndicesOverLimit() {
                 + totalShardsBefore
                 + "]/["
                 + dataNodes * shardsPerNode
-                + "] maximum normal shards open;";
+                + "] maximum normal shards open; for more information, see "
+                + ReferenceDocs.MAX_SHARDS_PER_NODE
+                + ";";
             assertEquals(expectedError, e.getMessage());
         }
         Metadata clusterState = clusterAdmin().prepareState().get().getState().metadata();
@@ -403,7 +408,9 @@ private void verifyException(int dataNodes, ShardCounts counts, IllegalArgumentE
             + currentShards
             + "]/["
             + maxShards
-            + "] maximum normal shards open;";
+            + "] maximum normal shards open; for more information, see "
+            + ReferenceDocs.MAX_SHARDS_PER_NODE
+            + ";";
         assertEquals(expectedError, e.getMessage());
     }
 

server/src/main/java/org/elasticsearch/common/ReferenceDocs.java

@@ -78,6 +78,7 @@ public enum ReferenceDocs {
     SNAPSHOT_REPOSITORY_ANALYSIS,
     S3_COMPATIBLE_REPOSITORIES,
     LUCENE_MAX_DOCS_LIMIT,
+    MAX_SHARDS_PER_NODE,
     // this comment keeps the ';' on the next line so every entry above has a trailing ',' which makes the diff for adding new links cleaner
     ;
 

server/src/main/java/org/elasticsearch/indices/ShardLimitValidator.java

@@ -13,6 +13,7 @@
 import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.cluster.node.DiscoveryNodeRole;
 import org.elasticsearch.cluster.service.ClusterService;
+import org.elasticsearch.common.ReferenceDocs;
 import org.elasticsearch.common.ValidationException;
 import org.elasticsearch.common.settings.Setting;
 import org.elasticsearch.common.settings.Settings;
@@ -296,7 +297,8 @@ static String errorMessageFrom(Result result) {
             + result.maxShardsInCluster
             + "] maximum "
             + result.group
-            + " shards open";
+            + " shards open; for more information, see "
+            + ReferenceDocs.MAX_SHARDS_PER_NODE;
     }
 
     /**

server/src/main/resources/org/elasticsearch/common/reference-docs-links.json

@@ -38,5 +38,6 @@
   "NETWORK_BINDING_AND_PUBLISHING": "modules-network.html#modules-network-binding-publishing",
   "SNAPSHOT_REPOSITORY_ANALYSIS": "repo-analysis-api.html",
   "S3_COMPATIBLE_REPOSITORIES": "repository-s3.html#repository-s3-compatible-services",
-  "LUCENE_MAX_DOCS_LIMIT": "size-your-shards.html#troubleshooting-max-docs-limit"
+  "LUCENE_MAX_DOCS_LIMIT": "size-your-shards.html#troubleshooting-max-docs-limit",
+  "MAX_SHARDS_PER_NODE": "size-your-shards.html#troubleshooting-max-shards-open"
 }

server/src/test/java/org/elasticsearch/indices/ShardLimitValidatorTests.java

@@ -17,6 +17,7 @@
 import org.elasticsearch.cluster.node.DiscoveryNodes;
 import org.elasticsearch.cluster.service.ClusterService;
 import org.elasticsearch.cluster.shards.ShardCounts;
+import org.elasticsearch.common.ReferenceDocs;
 import org.elasticsearch.common.ValidationException;
 import org.elasticsearch.common.settings.ClusterSettings;
 import org.elasticsearch.common.settings.Setting;
@@ -79,7 +80,8 @@ private void testOverShardLimit(CheckShardLimitMethod targetMethod, String group
                 + maxShards
                 + "] maximum "
                 + group
-                + " shards open",
+                + " shards open; for more information, see "
+                + ReferenceDocs.MAX_SHARDS_PER_NODE,
             ShardLimitValidator.errorMessageFrom(shardLimitsResult)
         );
         assertEquals(shardLimitsResult.maxShardsInCluster(), maxShards);
@@ -151,7 +153,9 @@ public void testValidateShardLimitOpenIndices() {
                 + maxShards
                 + "] maximum "
                 + group
-                + " shards open;",
+                + " shards open; for more information, see "
+                + ReferenceDocs.MAX_SHARDS_PER_NODE
+                + ";",
             exception.getMessage()
         );
     }
@@ -179,7 +183,9 @@ public void testValidateShardLimitUpdateReplicas() {
                 + shardsPerNode * nodesInCluster
                 + "] maximum "
                 + group
-                + " shards open;",
+                + " shards open; for more information, see "
+                + ReferenceDocs.MAX_SHARDS_PER_NODE
+                + ";",
             exception.getMessage()
         );
     }