Add support for CPU ranges in desired nodes

docs/changelog/86434.yaml

@@ -0,0 +1,5 @@
+pr: 86434
+summary: Add support for CPU ranges in desired nodes
+area: Autoscaling
+type: enhancement
+issues: []

docs/reference/cluster/delete-desired-nodes.asciidoc

@@ -25,9 +25,9 @@ PUT /_internal/desired_nodes/history/1
                  "node.attr.data" : "hot",
                  "node.attr.logical_availability_zone" : "zone-0"
             },
-            "processors" : 8,
+            "processors" : 8.0,
             "memory" : "58gb",
-            "storage" : "1700gb",
+            "storage" : "2tb",
             "node_version" : "{version}"
         }
     ]

docs/reference/cluster/get-desired-nodes.asciidoc

@@ -25,9 +25,9 @@ PUT /_internal/desired_nodes/my_history/1
                  "node.attr.data" : "hot",
                  "node.attr.logical_availability_zone" : "zone-0"
             },
-            "processors" : 8,
+            "processors" : 8.0,
             "memory" : "59gb",
-            "storage" : "1700gb",
+            "storage" : "2tb",
             "node_version" : "{version}"
         }
     ]

docs/reference/cluster/update-desired-nodes.asciidoc

@@ -24,9 +24,9 @@ PUT /_internal/desired_nodes/<history_id>/<version>
                  "node.attr.data" : "hot",
                  "node.attr.logical_availability_zone" : "zone-0"
             },
-            "processors" : 8,
+            "processors" : 8.0,
             "memory" : "58gb",
-            "storage" : "1700gb",
+            "storage" : "2tb",
             "node_version" : "{version}"
         }
     ]
@@ -77,9 +77,9 @@ PUT /_internal/desired_nodes/Ywkh3INLQcuPT49f6kcppA/100
                  "node.attr.data" : "hot",
                  "node.attr.logical_availability_zone" : "zone-0"
             },
-            "processors" : 8,
+            "processors" : 8.0,
             "memory" : "58gb",
-            "storage" : "1700gb",
+            "storage" : "2tb",
             "node_version" : "{version}"
         }
     ]
@@ -96,6 +96,34 @@ The API returns the following result:
 }
 --------------------------------------------------
 
+Additionally, it is possible to specify a processors range.
+This is helpful in environments where Elasticsearch nodes can
+be deployed in hosts where the number of processors that the
+Elasticsearch process can use is guaranteed to be at least the
+lower range and up to the upper range. This is a common scenario
+in Linux deployments where cgroups is used.
+[source,console]
+--------------------------------------------------
+PUT /_internal/desired_nodes/Ywkh3INLQcuPT49f6kcppA/101
+{
+    "nodes" : [
+        {
+            "settings" : {
+                 "node.name" : "instance-000187",
+                 "node.external_id": "instance-000187",
+                 "node.roles" : ["data_hot", "master"],
+                 "node.attr.data" : "hot",
+                 "node.attr.logical_availability_zone" : "zone-0"
+            },
+            "processors_range" : {"min": 8.0, "max": 10.0},
+            "memory" : "58gb",
+            "storage" : "2tb",
+            "node_version" : "{version}"
+        }
+    ]
+}
+--------------------------------------------------
+
 //////////////////////////
 
 [source,console]

libs/x-content/src/main/java/org/elasticsearch/xcontent/ObjectParser.java

@@ -751,7 +751,7 @@ public enum ValueType {
         OBJECT_ARRAY_OR_NULL(START_OBJECT, START_ARRAY, VALUE_NULL),
         OBJECT_OR_BOOLEAN(START_OBJECT, VALUE_BOOLEAN),
         OBJECT_OR_STRING(START_OBJECT, VALUE_STRING),
-        OBJECT_OR_LONG(START_OBJECT, VALUE_NUMBER),
+        OBJECT_OR_NUMBER(START_OBJECT, VALUE_NUMBER),
         OBJECT_ARRAY_BOOLEAN_OR_STRING(START_OBJECT, START_ARRAY, VALUE_BOOLEAN, VALUE_STRING),
         OBJECT_ARRAY_OR_STRING(START_OBJECT, START_ARRAY, VALUE_STRING),
         OBJECT_ARRAY_STRING_OR_NUMBER(START_OBJECT, START_ARRAY, VALUE_STRING, VALUE_NUMBER),

modules/reindex/src/main/java/org/elasticsearch/reindex/remote/RemoteResponseParsers.java

@@ -102,7 +102,7 @@ class Fields {
                 // For BWC with nodes pre 7.0
                 return p.longValue();
             }
-        }, new ParseField("total"), ValueType.OBJECT_OR_LONG);
+        }, new ParseField("total"), ValueType.OBJECT_OR_NUMBER);
         HITS_PARSER.declareObjectArray(constructorArg(), HIT_PARSER, new ParseField("hits"));
     }
 

qa/rolling-upgrade/src/test/java/org/elasticsearch/upgrades/DesiredNodesUpgradeIT.java

@@ -0,0 +1,117 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+package org.elasticsearch.upgrades;
+
+import org.elasticsearch.Version;
+import org.elasticsearch.client.Request;
+import org.elasticsearch.client.Response;
+import org.elasticsearch.client.ResponseException;
+import org.elasticsearch.cluster.metadata.DesiredNode;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.is;
+
+public class DesiredNodesUpgradeIT extends AbstractRollingTestCase {
+    public void testUpgradeDesiredNodes() throws Exception {
+        // Desired nodes was introduced in 8.1
+        if (UPGRADE_FROM_VERSION.before(Version.V_8_1_0)) {
+            return;
+        }
+
+        switch (CLUSTER_TYPE) {
+            case OLD -> {
+                var response = updateDesiredNodes(1, desiredNodesWithIntegerProcessor());
+                var statusCode = response.getStatusLine().getStatusCode();
+                assertThat(statusCode, equalTo(200));
+            }
+            case MIXED -> {
+                final var historyVersion = FIRST_MIXED_ROUND ? 2 : 3;
+                if (UPGRADE_FROM_VERSION.onOrAfter(DesiredNode.RANGE_FLOAT_PROCESSORS_SUPPORT_VERSION)) {
+                    var response = updateDesiredNodes(historyVersion, desiredNodesWithRangeOrFloatProcessors());
+                    var statusCode = response.getStatusLine().getStatusCode();
+                    assertThat(statusCode, equalTo(200));
+                } else {
+                    // Processor ranges or float processors are forbidden during upgrades: 8.2 -> 8.3 clusters
+                    final var responseException = expectThrows(
+                        ResponseException.class,
+                        () -> updateDesiredNodes(historyVersion, desiredNodesWithRangeOrFloatProcessors())
+                    );
+                    var statusCode = responseException.getResponse().getStatusLine().getStatusCode();
+                    assertThat(statusCode, is(equalTo(400)));
+                }
+            }
+            case UPGRADED -> {
+                var response = updateDesiredNodes(4, desiredNodesWithRangeOrFloatProcessors());
+                var statusCode = response.getStatusLine().getStatusCode();
+                assertThat(statusCode, equalTo(200));
+            }
+        }
+
+        final var getDesiredNodesRequest = new Request("GET", "/_internal/desired_nodes/_latest");
+        Response response = client().performRequest(getDesiredNodesRequest);
+        assertThat(response.getStatusLine().getStatusCode(), is(equalTo(200)));
+    }
+
+    private Response updateDesiredNodes(int version, String body) throws Exception {
+        final var updateDesiredNodesRequest = new Request("PUT", "/_internal/desired_nodes/history/" + version);
+        updateDesiredNodesRequest.setJsonEntity(body);
+        return client().performRequest(updateDesiredNodesRequest);
+    }
+
+    private String desiredNodesWithRangeOrFloatProcessors() {
+        if (randomBoolean()) {
+            return """
+                {
+                    "nodes" : [
+                        {
+                            "settings" : {
+                                 "node.name" : "instance-000187"
+                            },
+                            "processors_range" : {"min": 9.0, "max": 10.0},
+                            "memory" : "58gb",
+                            "storage" : "1tb",
+                            "node_version" : "99.1.0"
+                        }
+                    ]
+                }""";
+        } else {
+            return """
+                {
+                    "nodes" : [
+                        {
+                            "settings" : {
+                                 "node.name" : "instance-000187"
+                            },
+                            "processors" : 9.5,
+                            "memory" : "58gb",
+                            "storage" : "1tb",
+                            "node_version" : "99.1.0"
+                        }
+                    ]
+                }""";
+        }
+    }
+
+    private String desiredNodesWithIntegerProcessor() {
+        return """
+            {
+                "nodes" : [
+                    {
+                        "settings" : {
+                             "node.name" : "instance-000187"
+                        },
+                        "processors" : 9,
+                        "memory" : "58gb",
+                        "storage" : "1tb",
+                        "node_version" : "99.1.0"
+                    }
+                ]
+            }""";
+    }
+}