[7.x] [ML][Inference] adding .ml-inference* index and storage (#47267) (#47310)

* [ML][Inference] adding .ml-inference* index and storage (#47267)

* [ML][Inference] adding .ml-inference* index and storage

* Addressing PR comments

* Allowing null definition, adding validation tests for model config

* fixing line length

* adjusting for backport

client/rest-high-level/src/main/java/org/elasticsearch/client/common/TimeUtil.java

@@ -16,7 +16,7 @@
  * specific language governing permissions and limitations
  * under the License.
  */
-package org.elasticsearch.client.transform.transforms.util;
+package org.elasticsearch.client.common;
 
 import org.elasticsearch.common.time.DateFormatters;
 import org.elasticsearch.common.xcontent.XContentParser;
@@ -46,6 +46,14 @@ public final class TimeUtil {
             "unexpected token [" + parser.currentToken() + "] for [" + fieldName + "]");
     }
 
+    /**
+     * Parse out an Instant object given the current parser and field name.
+     *
+     * @param parser current XContentParser
+     * @param fieldName the field's preferred name (utilized in exception)
+     * @return parsed Instant object
+     * @throws IOException from XContentParser
+     */
     public static Instant parseTimeFieldToInstant(XContentParser parser, String fieldName) throws IOException {
         if (parser.currentToken() == XContentParser.Token.VALUE_NUMBER) {
             return Instant.ofEpochMilli(parser.longValue());

client/rest-high-level/src/main/java/org/elasticsearch/client/ml/calendars/ScheduledEvent.java

@@ -18,7 +18,7 @@
  */
 package org.elasticsearch.client.ml.calendars;
 
-import org.elasticsearch.client.ml.job.util.TimeUtil;
+import org.elasticsearch.client.common.TimeUtil;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.xcontent.ConstructingObjectParser;

client/rest-high-level/src/main/java/org/elasticsearch/client/ml/dataframe/DataFrameAnalyticsConfig.java

@@ -20,7 +20,7 @@
 package org.elasticsearch.client.ml.dataframe;
 
 import org.elasticsearch.Version;
-import org.elasticsearch.client.transform.transforms.util.TimeUtil;
+import org.elasticsearch.client.common.TimeUtil;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.Strings;

client/rest-high-level/src/main/java/org/elasticsearch/client/ml/inference/NamedXContentObject.java

@@ -0,0 +1,34 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.elasticsearch.client.ml.inference;
+
+import org.elasticsearch.common.xcontent.ToXContentObject;
+
+/**
+ * Simple interface for XContent Objects that are named.
+ *
+ * This affords more general handling when serializing and de-serializing this type of XContent when it is used in a NamedObjects
+ * parser.
+ */
+public interface NamedXContentObject extends ToXContentObject {
+    /**
+     * @return The name of the XContentObject that is to be serialized
+     */
+    String getName();
+}

client/rest-high-level/src/main/java/org/elasticsearch/client/ml/inference/NamedXContentObjectHelper.java

@@ -0,0 +1,57 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.elasticsearch.client.ml.inference;
+
+import org.elasticsearch.common.xcontent.ToXContent;
+import org.elasticsearch.common.xcontent.XContentBuilder;
+
+import java.io.IOException;
+import java.util.List;
+
+public final class NamedXContentObjectHelper {
+
+    private NamedXContentObjectHelper() {}
+
+    public static XContentBuilder writeNamedObjects(XContentBuilder builder,
+                                                    ToXContent.Params params,
+                                                    boolean useExplicitOrder,
+                                                    String namedObjectsName,
+                                                    List<? extends NamedXContentObject> namedObjects) throws IOException {
+        if (useExplicitOrder) {
+            builder.startArray(namedObjectsName);
+        } else {
+            builder.startObject(namedObjectsName);
+        }
+        for (NamedXContentObject object : namedObjects) {
+            if (useExplicitOrder) {
+                builder.startObject();
+            }
+            builder.field(object.getName(), object, params);
+            if (useExplicitOrder) {
+                builder.endObject();
+            }
+        }
+        if (useExplicitOrder) {
+            builder.endArray();
+        } else {
+            builder.endObject();
+        }
+        return builder;
+    }
+}

client/rest-high-level/src/main/java/org/elasticsearch/client/ml/inference/TrainedModelConfig.java

@@ -0,0 +1,299 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.elasticsearch.client.ml.inference;
+
+import org.elasticsearch.Version;
+import org.elasticsearch.client.common.TimeUtil;
+import org.elasticsearch.client.ml.inference.trainedmodel.TrainedModel;
+import org.elasticsearch.common.ParseField;
+import org.elasticsearch.common.Strings;
+import org.elasticsearch.common.xcontent.ObjectParser;
+import org.elasticsearch.common.xcontent.ToXContentObject;
+import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.time.Instant;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+
+public class TrainedModelConfig implements ToXContentObject {
+
+    public static final String NAME = "trained_model_doc";
+
+    public static final ParseField MODEL_ID = new ParseField("model_id");
+    public static final ParseField CREATED_BY = new ParseField("created_by");
+    public static final ParseField VERSION = new ParseField("version");
+    public static final ParseField DESCRIPTION = new ParseField("description");
+    public static final ParseField CREATED_TIME = new ParseField("created_time");
+    public static final ParseField MODEL_VERSION = new ParseField("model_version");
+    public static final ParseField DEFINITION = new ParseField("definition");
+    public static final ParseField MODEL_TYPE = new ParseField("model_type");
+    public static final ParseField METADATA = new ParseField("metadata");
+
+    public static final ObjectParser<Builder, Void> PARSER = new ObjectParser<>(NAME,
+            true,
+            TrainedModelConfig.Builder::new);
+    static {
+        PARSER.declareString(TrainedModelConfig.Builder::setModelId, MODEL_ID);
+        PARSER.declareString(TrainedModelConfig.Builder::setCreatedBy, CREATED_BY);
+        PARSER.declareString(TrainedModelConfig.Builder::setVersion, VERSION);
+        PARSER.declareString(TrainedModelConfig.Builder::setDescription, DESCRIPTION);
+        PARSER.declareField(TrainedModelConfig.Builder::setCreatedTime,
+            (p, c) -> TimeUtil.parseTimeFieldToInstant(p, CREATED_TIME.getPreferredName()),
+            CREATED_TIME,
+            ObjectParser.ValueType.VALUE);
+        PARSER.declareLong(TrainedModelConfig.Builder::setModelVersion, MODEL_VERSION);
+        PARSER.declareString(TrainedModelConfig.Builder::setModelType, MODEL_TYPE);
+        PARSER.declareObject(TrainedModelConfig.Builder::setMetadata, (p, c) -> p.map(), METADATA);
+        PARSER.declareNamedObjects(TrainedModelConfig.Builder::setDefinition,
+            (p, c, n) -> p.namedObject(TrainedModel.class, n, null),
+            (modelDocBuilder) -> { /* Noop does not matter client side */ },
+            DEFINITION);
+    }
+
+    public static TrainedModelConfig.Builder fromXContent(XContentParser parser) throws IOException {
+        return PARSER.parse(parser, null);
+    }
+
+    private final String modelId;
+    private final String createdBy;
+    private final Version version;
+    private final String description;
+    private final Instant createdTime;
+    private final Long modelVersion;
+    private final String modelType;
+    private final Map<String, Object> metadata;
+    private final TrainedModel definition;
+
+    TrainedModelConfig(String modelId,
+                       String createdBy,
+                       Version version,
+                       String description,
+                       Instant createdTime,
+                       Long modelVersion,
+                       String modelType,
+                       TrainedModel definition,
+                       Map<String, Object> metadata) {
+        this.modelId = modelId;
+        this.createdBy = createdBy;
+        this.version = version;
+        this.createdTime = Instant.ofEpochMilli(createdTime.toEpochMilli());
+        this.modelType = modelType;
+        this.definition = definition;
+        this.description = description;
+        this.metadata = metadata == null ? null : Collections.unmodifiableMap(metadata);
+        this.modelVersion = modelVersion;
+    }
+
+    public String getModelId() {
+        return modelId;
+    }
+
+    public String getCreatedBy() {
+        return createdBy;
+    }
+
+    public Version getVersion() {
+        return version;
+    }
+
+    public String getDescription() {
+        return description;
+    }
+
+    public Instant getCreatedTime() {
+        return createdTime;
+    }
+
+    public Long getModelVersion() {
+        return modelVersion;
+    }
+
+    public String getModelType() {
+        return modelType;
+    }
+
+    public Map<String, Object> getMetadata() {
+        return metadata;
+    }
+
+    public TrainedModel getDefinition() {
+        return definition;
+    }
+
+    public static Builder builder() {
+        return new Builder();
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject();
+        if (modelId != null) {
+            builder.field(MODEL_ID.getPreferredName(), modelId);
+        }
+        if (createdBy != null) {
+            builder.field(CREATED_BY.getPreferredName(), createdBy);
+        }
+        if (version != null) {
+            builder.field(VERSION.getPreferredName(), version.toString());
+        }
+        if (description != null) {
+            builder.field(DESCRIPTION.getPreferredName(), description);
+        }
+        if (createdTime != null) {
+            builder.timeField(CREATED_TIME.getPreferredName(), CREATED_TIME.getPreferredName() + "_string", createdTime.toEpochMilli());
+        }
+        if (modelVersion != null) {
+            builder.field(MODEL_VERSION.getPreferredName(), modelVersion);
+        }
+        if (modelType != null) {
+            builder.field(MODEL_TYPE.getPreferredName(), modelType);
+        }
+        if (definition != null) {
+            NamedXContentObjectHelper.writeNamedObjects(builder,
+                params,
+                false,
+                DEFINITION.getPreferredName(),
+                Collections.singletonList(definition));
+        }
+        if (metadata != null) {
+            builder.field(METADATA.getPreferredName(), metadata);
+        }
+        builder.endObject();
+        return builder;
+    }
+
+    @Override
+    public String toString() {
+        return Strings.toString(this);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        TrainedModelConfig that = (TrainedModelConfig) o;
+        return Objects.equals(modelId, that.modelId) &&
+            Objects.equals(createdBy, that.createdBy) &&
+            Objects.equals(version, that.version) &&
+            Objects.equals(description, that.description) &&
+            Objects.equals(createdTime, that.createdTime) &&
+            Objects.equals(modelVersion, that.modelVersion) &&
+            Objects.equals(modelType, that.modelType) &&
+            Objects.equals(definition, that.definition) &&
+            Objects.equals(metadata, that.metadata);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(modelId,
+            createdBy,
+            version,
+            createdTime,
+            modelType,
+            definition,
+            description,
+            metadata,
+            modelVersion);
+    }
+
+
+    public static class Builder {
+
+        private String modelId;
+        private String createdBy;
+        private Version version;
+        private String description;
+        private Instant createdTime;
+        private Long modelVersion;
+        private String modelType;
+        private Map<String, Object> metadata;
+        private TrainedModel definition;
+
+        public Builder setModelId(String modelId) {
+            this.modelId = modelId;
+            return this;
+        }
+
+        private Builder setCreatedBy(String createdBy) {
+            this.createdBy = createdBy;
+            return this;
+        }
+
+        private Builder setVersion(Version version) {
+            this.version = version;
+            return this;
+        }
+
+        private Builder setVersion(String version) {
+            return this.setVersion(Version.fromString(version));
+        }
+
+        public Builder setDescription(String description) {
+            this.description = description;
+            return this;
+        }
+
+        private Builder setCreatedTime(Instant createdTime) {
+            this.createdTime = createdTime;
+            return this;
+        }
+
+        public Builder setModelVersion(Long modelVersion) {
+            this.modelVersion = modelVersion;
+            return this;
+        }
+
+        public Builder setModelType(String modelType) {
+            this.modelType = modelType;
+            return this;
+        }
+
+        public Builder setMetadata(Map<String, Object> metadata) {
+            this.metadata = metadata;
+            return this;
+        }
+
+        public Builder setDefinition(TrainedModel definition) {
+            this.definition = definition;
+            return this;
+        }
+
+        private Builder setDefinition(List<TrainedModel> definition) {
+            assert definition.size() == 1;
+            return setDefinition(definition.get(0));
+        }
+
+        public TrainedModelConfig build() {
+            return new TrainedModelConfig(
+                modelId,
+                createdBy,
+                version,
+                description,
+                createdTime,
+                modelVersion,
+                modelType,
+                definition,
+                metadata);
+        }
+    }
+}

client/rest-high-level/src/main/java/org/elasticsearch/client/ml/inference/trainedmodel/TrainedModel.java

@@ -18,11 +18,11 @@
  */
 package org.elasticsearch.client.ml.inference.trainedmodel;
 
-import org.elasticsearch.common.xcontent.ToXContentObject;
+import org.elasticsearch.client.ml.inference.NamedXContentObject;
 
 import java.util.List;
 
-public interface TrainedModel extends ToXContentObject {
+public interface TrainedModel extends NamedXContentObject {
 
     /**
      * @return List of featureNames expected by the model. In the order that they are expected

client/rest-high-level/src/main/java/org/elasticsearch/client/ml/job/config/Job.java

@@ -18,7 +18,7 @@
  */
 package org.elasticsearch.client.ml.job.config;
 
-import org.elasticsearch.client.ml.job.util.TimeUtil;
+import org.elasticsearch.client.common.TimeUtil;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.unit.TimeValue;

client/rest-high-level/src/main/java/org/elasticsearch/client/ml/job/process/DataCounts.java

@@ -18,8 +18,8 @@
  */
 package org.elasticsearch.client.ml.job.process;
 
+import org.elasticsearch.client.common.TimeUtil;
 import org.elasticsearch.client.ml.job.config.Job;
-import org.elasticsearch.client.ml.job.util.TimeUtil;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.xcontent.ConstructingObjectParser;
 import org.elasticsearch.common.xcontent.ObjectParser.ValueType;

client/rest-high-level/src/main/java/org/elasticsearch/client/ml/job/process/ModelSizeStats.java

@@ -18,9 +18,9 @@
  */
 package org.elasticsearch.client.ml.job.process;
 
+import org.elasticsearch.client.common.TimeUtil;
 import org.elasticsearch.client.ml.job.config.Job;
 import org.elasticsearch.client.ml.job.results.Result;
-import org.elasticsearch.client.ml.job.util.TimeUtil;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.xcontent.ConstructingObjectParser;
 import org.elasticsearch.common.xcontent.ObjectParser.ValueType;

client/rest-high-level/src/main/java/org/elasticsearch/client/ml/job/process/ModelSnapshot.java

@@ -19,8 +19,8 @@
 package org.elasticsearch.client.ml.job.process;
 
 import org.elasticsearch.Version;
+import org.elasticsearch.client.common.TimeUtil;
 import org.elasticsearch.client.ml.job.config.Job;
-import org.elasticsearch.client.ml.job.util.TimeUtil;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.xcontent.ObjectParser;
 import org.elasticsearch.common.xcontent.ObjectParser.ValueType;

client/rest-high-level/src/main/java/org/elasticsearch/client/ml/job/results/AnomalyRecord.java

@@ -18,8 +18,8 @@
  */
 package org.elasticsearch.client.ml.job.results;
 
+import org.elasticsearch.client.common.TimeUtil;
 import org.elasticsearch.client.ml.job.config.Job;
-import org.elasticsearch.client.ml.job.util.TimeUtil;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.xcontent.ConstructingObjectParser;
 import org.elasticsearch.common.xcontent.ObjectParser.ValueType;

client/rest-high-level/src/main/java/org/elasticsearch/client/ml/job/results/Bucket.java

@@ -18,8 +18,8 @@
  */
 package org.elasticsearch.client.ml.job.results;
 
+import org.elasticsearch.client.common.TimeUtil;
 import org.elasticsearch.client.ml.job.config.Job;
-import org.elasticsearch.client.ml.job.util.TimeUtil;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.xcontent.ConstructingObjectParser;
 import org.elasticsearch.common.xcontent.ObjectParser.ValueType;

client/rest-high-level/src/main/java/org/elasticsearch/client/ml/job/results/BucketInfluencer.java

@@ -18,8 +18,8 @@
  */
 package org.elasticsearch.client.ml.job.results;
 
+import org.elasticsearch.client.common.TimeUtil;
 import org.elasticsearch.client.ml.job.config.Job;
-import org.elasticsearch.client.ml.job.util.TimeUtil;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.xcontent.ConstructingObjectParser;
 import org.elasticsearch.common.xcontent.ObjectParser.ValueType;

client/rest-high-level/src/main/java/org/elasticsearch/client/ml/job/results/Influencer.java

@@ -18,8 +18,8 @@
  */
 package org.elasticsearch.client.ml.job.results;
 
+import org.elasticsearch.client.common.TimeUtil;
 import org.elasticsearch.client.ml.job.config.Job;
-import org.elasticsearch.client.ml.job.util.TimeUtil;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.xcontent.ConstructingObjectParser;
 import org.elasticsearch.common.xcontent.ObjectParser.ValueType;

client/rest-high-level/src/main/java/org/elasticsearch/client/ml/job/results/OverallBucket.java

@@ -18,8 +18,8 @@
  */
 package org.elasticsearch.client.ml.job.results;
 
+import org.elasticsearch.client.common.TimeUtil;
 import org.elasticsearch.client.ml.job.config.Job;
-import org.elasticsearch.client.ml.job.util.TimeUtil;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.xcontent.ConstructingObjectParser;
 import org.elasticsearch.common.xcontent.ObjectParser;

client/rest-high-level/src/main/java/org/elasticsearch/client/ml/job/util/TimeUtil.java

@@ -1,48 +0,0 @@
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-package org.elasticsearch.client.ml.job.util;
-
-import org.elasticsearch.common.time.DateFormatters;
-import org.elasticsearch.common.xcontent.XContentParser;
-
-import java.io.IOException;
-import java.time.format.DateTimeFormatter;
-import java.util.Date;
-
-public final class TimeUtil {
-
-    /**
-     * Parse out a Date object given the current parser and field name.
-     *
-     * @param parser current XContentParser
-     * @param fieldName the field's preferred name (utilized in exception)
-     * @return parsed Date object
-     * @throws IOException from XContentParser
-     */
-    public static Date parseTimeField(XContentParser parser, String fieldName) throws IOException {
-        if (parser.currentToken() == XContentParser.Token.VALUE_NUMBER) {
-            return new Date(parser.longValue());
-        } else if (parser.currentToken() == XContentParser.Token.VALUE_STRING) {
-            return new Date(DateFormatters.from(DateTimeFormatter.ISO_INSTANT.parse(parser.text())).toInstant().toEpochMilli());
-        }
-        throw new IllegalArgumentException(
-            "unexpected token [" + parser.currentToken() + "] for [" + fieldName + "]");
-    }
-
-}

client/rest-high-level/src/main/java/org/elasticsearch/client/transform/transforms/TransformCheckpointingInfo.java

@@ -19,7 +19,7 @@
 
 package org.elasticsearch.client.transform.transforms;
 
-import org.elasticsearch.client.transform.transforms.util.TimeUtil;
+import org.elasticsearch.client.common.TimeUtil;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.xcontent.ConstructingObjectParser;

client/rest-high-level/src/main/java/org/elasticsearch/client/transform/transforms/TransformConfig.java

@@ -20,8 +20,8 @@
 package org.elasticsearch.client.transform.transforms;
 
 import org.elasticsearch.Version;
+import org.elasticsearch.client.common.TimeUtil;
 import org.elasticsearch.client.transform.transforms.pivot.PivotConfig;
-import org.elasticsearch.client.transform.transforms.util.TimeUtil;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.Strings;

client/rest-high-level/src/test/java/org/elasticsearch/client/ml/inference/NamedXContentObjectHelperTests.java

@@ -0,0 +1,112 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.elasticsearch.client.ml.inference;
+
+import org.elasticsearch.common.ParseField;
+import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.NamedXContentRegistry;
+import org.elasticsearch.common.xcontent.ObjectParser;
+import org.elasticsearch.common.xcontent.ToXContent;
+import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.search.SearchModule;
+import org.elasticsearch.test.ESTestCase;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+import static org.hamcrest.Matchers.equalTo;
+
+public class NamedXContentObjectHelperTests extends ESTestCase {
+
+    static class NamedTestObject implements NamedXContentObject {
+
+        private String fieldValue;
+        public static final ObjectParser<NamedTestObject, Void> PARSER =
+            new ObjectParser<>("my_named_object", true, NamedTestObject::new);
+        static {
+            PARSER.declareString(NamedTestObject::setFieldValue, new ParseField("my_field"));
+        }
+
+        NamedTestObject() {
+
+        }
+
+        NamedTestObject(String value) {
+            this.fieldValue = value;
+        }
+
+        @Override
+        public String getName() {
+            return "my_named_object";
+        }
+
+        public void setFieldValue(String value) {
+            this.fieldValue = value;
+        }
+
+        @Override
+        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+            builder.startObject();
+            if (fieldValue != null) {
+                builder.field("my_field", fieldValue);
+            }
+            builder.endObject();
+            return builder;
+        }
+    }
+
+    public void testSerializeInOrder() throws IOException {
+        String expected =
+            "{\"my_objects\":[{\"my_named_object\":{\"my_field\":\"value1\"}},{\"my_named_object\":{\"my_field\":\"value2\"}}]}";
+        try (XContentBuilder builder = XContentFactory.jsonBuilder()) {
+            builder.startObject();
+            List<NamedXContentObject> objects = Arrays.asList(new NamedTestObject("value1"), new NamedTestObject("value2"));
+            NamedXContentObjectHelper.writeNamedObjects(builder, ToXContent.EMPTY_PARAMS, true, "my_objects", objects);
+            builder.endObject();
+            assertThat(BytesReference.bytes(builder).utf8ToString(), equalTo(expected));
+        }
+    }
+
+    public void testSerialize() throws IOException {
+        String expected = "{\"my_objects\":{\"my_named_object\":{\"my_field\":\"value1\"},\"my_named_object\":{\"my_field\":\"value2\"}}}";
+        try (XContentBuilder builder = XContentFactory.jsonBuilder()) {
+            builder.startObject();
+            List<NamedXContentObject> objects = Arrays.asList(new NamedTestObject("value1"), new NamedTestObject("value2"));
+            NamedXContentObjectHelper.writeNamedObjects(builder, ToXContent.EMPTY_PARAMS, false, "my_objects", objects);
+            builder.endObject();
+            assertThat(BytesReference.bytes(builder).utf8ToString(), equalTo(expected));
+        }
+    }
+
+    @Override
+    protected NamedXContentRegistry xContentRegistry() {
+        List<NamedXContentRegistry.Entry> namedXContent = new ArrayList<>();
+        namedXContent.addAll(Collections.singletonList(new NamedXContentRegistry.Entry(NamedXContentObject.class,
+            new ParseField("my_named_object"),
+            (p, c) -> NamedTestObject.PARSER.apply(p, null))));
+        namedXContent.addAll(new SearchModule(Settings.EMPTY, false, Collections.emptyList()).getNamedXContents());
+        return new NamedXContentRegistry(namedXContent);
+    }
+
+}

client/rest-high-level/src/test/java/org/elasticsearch/client/ml/inference/TrainedModelConfigTests.java

@@ -0,0 +1,76 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.elasticsearch.client.ml.inference;
+
+import org.elasticsearch.Version;
+import org.elasticsearch.client.ml.inference.trainedmodel.tree.TreeTests;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.NamedXContentRegistry;
+import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.search.SearchModule;
+import org.elasticsearch.test.AbstractXContentTestCase;
+
+import java.io.IOException;
+import java.time.Instant;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.function.Predicate;
+
+
+public class TrainedModelConfigTests extends AbstractXContentTestCase<TrainedModelConfig> {
+
+    @Override
+    protected TrainedModelConfig doParseInstance(XContentParser parser) throws IOException {
+        return TrainedModelConfig.fromXContent(parser).build();
+    }
+
+    @Override
+    protected boolean supportsUnknownFields() {
+        return true;
+    }
+
+    @Override
+    protected Predicate<String> getRandomFieldsExcludeFilter() {
+        return field -> !field.isEmpty();
+    }
+
+    @Override
+    protected TrainedModelConfig createTestInstance() {
+        return new TrainedModelConfig(
+            randomAlphaOfLength(10),
+            randomAlphaOfLength(10),
+            Version.CURRENT,
+            randomBoolean() ? null : randomAlphaOfLength(100),
+            Instant.ofEpochMilli(randomNonNegativeLong()),
+            randomBoolean() ? null : randomNonNegativeLong(),
+            randomAlphaOfLength(10),
+            randomFrom(TreeTests.createRandom()),
+            randomBoolean() ? null : Collections.singletonMap(randomAlphaOfLength(10), randomAlphaOfLength(10)));
+    }
+
+    @Override
+    protected NamedXContentRegistry xContentRegistry() {
+        List<NamedXContentRegistry.Entry> namedXContent = new ArrayList<>();
+        namedXContent.addAll(new MlInferenceNamedXContentProvider().getNamedXContentParsers());
+        namedXContent.addAll(new SearchModule(Settings.EMPTY, false, Collections.emptyList()).getNamedXContents());
+        return new NamedXContentRegistry(namedXContent);
+    }
+
+}

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/inference/TrainedModelConfig.java

@@ -0,0 +1,372 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+package org.elasticsearch.xpack.core.ml.inference;
+
+import org.elasticsearch.Version;
+import org.elasticsearch.common.Nullable;
+import org.elasticsearch.common.ParseField;
+import org.elasticsearch.common.Strings;
+import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.common.io.stream.Writeable;
+import org.elasticsearch.common.xcontent.ObjectParser;
+import org.elasticsearch.common.xcontent.ToXContentObject;
+import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.xpack.core.common.time.TimeUtils;
+import org.elasticsearch.xpack.core.ml.inference.trainedmodel.LenientlyParsedTrainedModel;
+import org.elasticsearch.xpack.core.ml.inference.trainedmodel.StrictlyParsedTrainedModel;
+import org.elasticsearch.xpack.core.ml.inference.trainedmodel.TrainedModel;
+import org.elasticsearch.xpack.core.ml.job.messages.Messages;
+import org.elasticsearch.xpack.core.ml.utils.ExceptionsHelper;
+import org.elasticsearch.xpack.core.ml.utils.MlStrings;
+import org.elasticsearch.xpack.core.ml.utils.NamedXContentObjectHelper;
+
+import java.io.IOException;
+import java.time.Instant;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+
+public class TrainedModelConfig implements ToXContentObject, Writeable {
+
+    public static final String NAME = "trained_model_doc";
+
+    public static final ParseField MODEL_ID = new ParseField("model_id");
+    public static final ParseField CREATED_BY = new ParseField("created_by");
+    public static final ParseField VERSION = new ParseField("version");
+    public static final ParseField DESCRIPTION = new ParseField("description");
+    public static final ParseField CREATED_TIME = new ParseField("created_time");
+    public static final ParseField MODEL_VERSION = new ParseField("model_version");
+    public static final ParseField DEFINITION = new ParseField("definition");
+    public static final ParseField MODEL_TYPE = new ParseField("model_type");
+    public static final ParseField METADATA = new ParseField("metadata");
+
+    // These parsers follow the pattern that metadata is parsed leniently (to allow for enhancements), whilst config is parsed strictly
+    public static final ObjectParser<TrainedModelConfig.Builder, Void> LENIENT_PARSER = createParser(true);
+    public static final ObjectParser<TrainedModelConfig.Builder, Void> STRICT_PARSER = createParser(false);
+
+    private static ObjectParser<TrainedModelConfig.Builder, Void> createParser(boolean ignoreUnknownFields) {
+        ObjectParser<TrainedModelConfig.Builder, Void> parser = new ObjectParser<>(NAME,
+            ignoreUnknownFields,
+            TrainedModelConfig.Builder::new);
+        parser.declareString(TrainedModelConfig.Builder::setModelId, MODEL_ID);
+        parser.declareString(TrainedModelConfig.Builder::setCreatedBy, CREATED_BY);
+        parser.declareString(TrainedModelConfig.Builder::setVersion, VERSION);
+        parser.declareString(TrainedModelConfig.Builder::setDescription, DESCRIPTION);
+        parser.declareField(TrainedModelConfig.Builder::setCreatedTime,
+            (p, c) -> TimeUtils.parseTimeFieldToInstant(p, CREATED_TIME.getPreferredName()),
+            CREATED_TIME,
+            ObjectParser.ValueType.VALUE);
+        parser.declareLong(TrainedModelConfig.Builder::setModelVersion, MODEL_VERSION);
+        parser.declareString(TrainedModelConfig.Builder::setModelType, MODEL_TYPE);
+        parser.declareObject(TrainedModelConfig.Builder::setMetadata, (p, c) -> p.map(), METADATA);
+        parser.declareNamedObjects(TrainedModelConfig.Builder::setDefinition,
+            (p, c, n) -> ignoreUnknownFields ?
+                p.namedObject(LenientlyParsedTrainedModel.class, n, null) :
+                p.namedObject(StrictlyParsedTrainedModel.class, n, null),
+            (modelDocBuilder) -> { /* Noop does not matter as we will throw if more than one is defined */ },
+            DEFINITION);
+        return parser;
+    }
+
+    public static TrainedModelConfig.Builder fromXContent(XContentParser parser, boolean lenient) throws IOException {
+        return lenient ? LENIENT_PARSER.parse(parser, null) : STRICT_PARSER.parse(parser, null);
+    }
+
+    public static String documentId(String modelId, long modelVersion) {
+        return NAME + "-" + modelId + "-" + modelVersion;
+    }
+
+
+    private final String modelId;
+    private final String createdBy;
+    private final Version version;
+    private final String description;
+    private final Instant createdTime;
+    private final long modelVersion;
+    private final String modelType;
+    private final Map<String, Object> metadata;
+    // TODO how to reference and store large models that will not be executed in Java???
+    // Potentially allow this to be null and have an {index: indexName, doc: model_doc_id} or something
+    // TODO Should this be lazily parsed when loading via the index???
+    private final TrainedModel definition;
+    TrainedModelConfig(String modelId,
+                       String createdBy,
+                       Version version,
+                       String description,
+                       Instant createdTime,
+                       Long modelVersion,
+                       String modelType,
+                       TrainedModel definition,
+                       Map<String, Object> metadata) {
+        this.modelId = ExceptionsHelper.requireNonNull(modelId, MODEL_ID);
+        this.createdBy = ExceptionsHelper.requireNonNull(createdBy, CREATED_BY);
+        this.version = ExceptionsHelper.requireNonNull(version, VERSION);
+        this.createdTime = Instant.ofEpochMilli(ExceptionsHelper.requireNonNull(createdTime, CREATED_TIME).toEpochMilli());
+        this.modelType = ExceptionsHelper.requireNonNull(modelType, MODEL_TYPE);
+        this.definition = definition;
+        this.description = description;
+        this.metadata = metadata == null ? null : Collections.unmodifiableMap(metadata);
+        this.modelVersion = modelVersion == null ? 0 : modelVersion;
+    }
+
+    public TrainedModelConfig(StreamInput in) throws IOException {
+        modelId = in.readString();
+        createdBy = in.readString();
+        version = Version.readVersion(in);
+        description = in.readOptionalString();
+        createdTime = in.readInstant();
+        modelVersion = in.readVLong();
+        modelType = in.readString();
+        definition = in.readOptionalNamedWriteable(TrainedModel.class);
+        metadata = in.readMap();
+    }
+
+    public String getModelId() {
+        return modelId;
+    }
+
+    public String getCreatedBy() {
+        return createdBy;
+    }
+
+    public Version getVersion() {
+        return version;
+    }
+
+    public String getDescription() {
+        return description;
+    }
+
+    public Instant getCreatedTime() {
+        return createdTime;
+    }
+
+    public long getModelVersion() {
+        return modelVersion;
+    }
+
+    public String getModelType() {
+        return modelType;
+    }
+
+    public Map<String, Object> getMetadata() {
+        return metadata;
+    }
+
+    @Nullable
+    public TrainedModel getDefinition() {
+        return definition;
+    }
+
+    public static Builder builder() {
+        return new Builder();
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeString(modelId);
+        out.writeString(createdBy);
+        Version.writeVersion(version, out);
+        out.writeOptionalString(description);
+        out.writeInstant(createdTime);
+        out.writeVLong(modelVersion);
+        out.writeString(modelType);
+        out.writeOptionalNamedWriteable(definition);
+        out.writeMap(metadata);
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject();
+        builder.field(MODEL_ID.getPreferredName(), modelId);
+        builder.field(CREATED_BY.getPreferredName(), createdBy);
+        builder.field(VERSION.getPreferredName(), version.toString());
+        if (description != null) {
+            builder.field(DESCRIPTION.getPreferredName(), description);
+        }
+        builder.timeField(CREATED_TIME.getPreferredName(), CREATED_TIME.getPreferredName() + "_string", createdTime.toEpochMilli());
+        builder.field(MODEL_VERSION.getPreferredName(), modelVersion);
+        builder.field(MODEL_TYPE.getPreferredName(), modelType);
+        if (definition != null) {
+            NamedXContentObjectHelper.writeNamedObjects(builder,
+                params,
+                false,
+                DEFINITION.getPreferredName(),
+                Collections.singletonList(definition));
+        }
+        if (metadata != null) {
+            builder.field(METADATA.getPreferredName(), metadata);
+        }
+        builder.endObject();
+        return builder;
+    }
+
+    @Override
+    public String toString() {
+        return Strings.toString(this);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        TrainedModelConfig that = (TrainedModelConfig) o;
+        return Objects.equals(modelId, that.modelId) &&
+            Objects.equals(createdBy, that.createdBy) &&
+            Objects.equals(version, that.version) &&
+            Objects.equals(description, that.description) &&
+            Objects.equals(createdTime, that.createdTime) &&
+            Objects.equals(modelVersion, that.modelVersion) &&
+            Objects.equals(modelType, that.modelType) &&
+            Objects.equals(definition, that.definition) &&
+            Objects.equals(metadata, that.metadata);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(modelId,
+            createdBy,
+            version,
+            createdTime,
+            modelType,
+            definition,
+            description,
+            metadata,
+            modelVersion);
+    }
+
+
+    public static class Builder {
+
+        private String modelId;
+        private String createdBy;
+        private Version version;
+        private String description;
+        private Instant createdTime;
+        private Long modelVersion;
+        private String modelType;
+        private Map<String, Object> metadata;
+        private TrainedModel definition;
+
+        public Builder setModelId(String modelId) {
+            this.modelId = modelId;
+            return this;
+        }
+
+        public Builder setCreatedBy(String createdBy) {
+            this.createdBy = createdBy;
+            return this;
+        }
+
+        public Builder setVersion(Version version) {
+            this.version = version;
+            return this;
+        }
+
+        private Builder setVersion(String version) {
+            return this.setVersion(Version.fromString(version));
+        }
+
+        public Builder setDescription(String description) {
+            this.description = description;
+            return this;
+        }
+
+        public Builder setCreatedTime(Instant createdTime) {
+            this.createdTime = createdTime;
+            return this;
+        }
+
+        public Builder setModelVersion(Long modelVersion) {
+            this.modelVersion = modelVersion;
+            return this;
+        }
+
+        public Builder setModelType(String modelType) {
+            this.modelType = modelType;
+            return this;
+        }
+
+        public Builder setMetadata(Map<String, Object> metadata) {
+            this.metadata = metadata;
+            return this;
+        }
+
+        public Builder setDefinition(TrainedModel definition) {
+            this.definition = definition;
+            return this;
+        }
+
+        private Builder setDefinition(List<TrainedModel> definition) {
+            if (definition.size() != 1) {
+                throw ExceptionsHelper.badRequestException("[{}] must have exactly one trained model defined.",
+                    DEFINITION.getPreferredName());
+            }
+            return setDefinition(definition.get(0));
+        }
+
+        // TODO move to REST level instead of here in the builder
+        public void validate() {
+            // We require a definition to be available until we support other means of supplying the definition
+            ExceptionsHelper.requireNonNull(definition, DEFINITION);
+            ExceptionsHelper.requireNonNull(modelId, MODEL_ID);
+
+            if (MlStrings.isValidId(modelId) == false) {
+                throw ExceptionsHelper.badRequestException(Messages.getMessage(Messages.INVALID_ID, MODEL_ID.getPreferredName(), modelId));
+            }
+
+            if (MlStrings.hasValidLengthForId(modelId) == false) {
+                throw ExceptionsHelper.badRequestException(Messages.getMessage(Messages.ID_TOO_LONG,
+                    MODEL_ID.getPreferredName(),
+                    modelId,
+                    MlStrings.ID_LENGTH_LIMIT));
+            }
+
+            if (version != null) {
+                throw ExceptionsHelper.badRequestException("illegal to set [{}] at inference model creation", VERSION.getPreferredName());
+            }
+
+            if (createdBy != null) {
+                throw ExceptionsHelper.badRequestException("illegal to set [{}] at inference model creation",
+                    CREATED_BY.getPreferredName());
+            }
+
+            if (createdTime != null) {
+                throw ExceptionsHelper.badRequestException("illegal to set [{}] at inference model creation",
+                    CREATED_TIME.getPreferredName());
+            }
+        }
+
+        public TrainedModelConfig build() {
+            return new TrainedModelConfig(
+                modelId,
+                createdBy,
+                version,
+                description,
+                createdTime,
+                modelVersion,
+                modelType,
+                definition,
+                metadata);
+        }
+
+        public TrainedModelConfig build(Version version) {
+            return new TrainedModelConfig(
+                modelId,
+                createdBy,
+                version,
+                description,
+                Instant.now(),
+                modelVersion,
+                modelType,
+                definition,
+                metadata);
+        }
+    }
+}

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/inference/persistence/InferenceIndexConstants.java

@@ -0,0 +1,20 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+package org.elasticsearch.xpack.core.ml.inference.persistence;
+
+/**
+ * Class containing the index constants so that the index version, name, and prefix are available to a wider audience.
+ */
+public final class InferenceIndexConstants {
+
+    public static final String INDEX_VERSION = "000001";
+    public static final String INDEX_NAME_PREFIX = ".ml-inference-";
+    public static final String INDEX_PATTERN = INDEX_NAME_PREFIX + "*";
+    public static final String LATEST_INDEX_NAME = INDEX_NAME_PREFIX + INDEX_VERSION;
+
+    private InferenceIndexConstants() {}
+
+}

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/job/messages/Messages.java

@@ -75,9 +75,16 @@ public final class Messages {
             "Inconsistent {0}; ''{1}'' specified in the body differs from ''{2}'' specified as a URL argument";
     public static final String INVALID_ID = "Invalid {0}; ''{1}'' can contain lowercase alphanumeric (a-z and 0-9), hyphens or " +
             "underscores; must start and end with alphanumeric";
+    public static final String ID_TOO_LONG = "Invalid {0}; ''{1}'' cannot contain more than {2} characters.";
     public static final String INVALID_GROUP = "Invalid group id ''{0}''; must be non-empty string and may contain lowercase alphanumeric" +
             " (a-z and 0-9), hyphens or underscores; must start and end with alphanumeric";
 
+    public static final String INFERENCE_TRAINED_MODEL_EXISTS = "Trained machine learning model [{0}] with version [{1}] already exists";
+    public static final String INFERENCE_FAILED_TO_STORE_MODEL = "Failed to store trained machine learning model [{0}]";
+    public static final String INFERENCE_FAILED_TO_SERIALIZE_MODEL =
+        "Failed to serialize the trained model [{0}] with version [{1}] for storage";
+    public static final String INFERENCE_NOT_FOUND = "Could not find trained model [{0}] with version [{1}]";
+
     public static final String JOB_AUDIT_DATAFEED_DATA_SEEN_AGAIN = "Datafeed has started retrieving data again";
     public static final String JOB_AUDIT_CREATED = "Job created";
     public static final String JOB_AUDIT_UPDATED = "Job updated: {0}";

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/utils/NamedXContentObjectHelper.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+package org.elasticsearch.xpack.core.ml.utils;
+
+import org.elasticsearch.common.xcontent.ToXContent;
+import org.elasticsearch.common.xcontent.XContentBuilder;
+
+import java.io.IOException;
+import java.util.List;
+
+public final class NamedXContentObjectHelper {
+
+    private NamedXContentObjectHelper() {}
+
+    public static XContentBuilder writeNamedObjects(XContentBuilder builder,
+                                                    ToXContent.Params params,
+                                                    boolean useExplicitOrder,
+                                                    String namedObjectsName,
+                                                    List<? extends NamedXContentObject> namedObjects) throws IOException {
+        if (useExplicitOrder) {
+            builder.startArray(namedObjectsName);
+        } else {
+            builder.startObject(namedObjectsName);
+        }
+        for (NamedXContentObject object : namedObjects) {
+            if (useExplicitOrder) {
+                builder.startObject();
+            }
+            builder.field(object.getName(), object, params);
+            if (useExplicitOrder) {
+                builder.endObject();
+            }
+        }
+        if (useExplicitOrder) {
+            builder.endArray();
+        } else {
+            builder.endObject();
+        }
+        return builder;
+    }
+}

x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/ml/inference/TrainedModelConfigTests.java

@@ -0,0 +1,134 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+package org.elasticsearch.xpack.core.ml.inference;
+
+import org.elasticsearch.ElasticsearchException;
+import org.elasticsearch.Version;
+import org.elasticsearch.common.io.stream.NamedWriteableRegistry;
+import org.elasticsearch.common.io.stream.Writeable;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.NamedXContentRegistry;
+import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.search.SearchModule;
+import org.elasticsearch.test.AbstractSerializingTestCase;
+import org.elasticsearch.xpack.core.ml.inference.trainedmodel.tree.TreeTests;
+import org.elasticsearch.xpack.core.ml.job.messages.Messages;
+import org.elasticsearch.xpack.core.ml.utils.MlStrings;
+import org.junit.Before;
+
+import java.io.IOException;
+import java.time.Instant;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.function.Predicate;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+import static org.hamcrest.Matchers.equalTo;
+
+
+public class TrainedModelConfigTests extends AbstractSerializingTestCase<TrainedModelConfig> {
+
+    private boolean lenient;
+
+    @Before
+    public void chooseStrictOrLenient() {
+        lenient = randomBoolean();
+    }
+
+    @Override
+    protected TrainedModelConfig doParseInstance(XContentParser parser) throws IOException {
+        return TrainedModelConfig.fromXContent(parser, lenient).build();
+    }
+
+    @Override
+    protected boolean supportsUnknownFields() {
+        return lenient;
+    }
+
+    @Override
+    protected Predicate<String> getRandomFieldsExcludeFilter() {
+        return field -> !field.isEmpty();
+    }
+
+    @Override
+    protected TrainedModelConfig createTestInstance() {
+        return new TrainedModelConfig(
+            randomAlphaOfLength(10),
+            randomAlphaOfLength(10),
+            Version.CURRENT,
+            randomBoolean() ? null : randomAlphaOfLength(100),
+            Instant.ofEpochMilli(randomNonNegativeLong()),
+            randomBoolean() ? null : randomNonNegativeLong(),
+            randomAlphaOfLength(10),
+            randomBoolean() ? null : randomFrom(TreeTests.createRandom()),
+            randomBoolean() ? null : Collections.singletonMap(randomAlphaOfLength(10), randomAlphaOfLength(10)));
+    }
+
+    @Override
+    protected Writeable.Reader<TrainedModelConfig> instanceReader() {
+        return TrainedModelConfig::new;
+    }
+
+    @Override
+    protected NamedXContentRegistry xContentRegistry() {
+        List<NamedXContentRegistry.Entry> namedXContent = new ArrayList<>();
+        namedXContent.addAll(new MlInferenceNamedXContentProvider().getNamedXContentParsers());
+        namedXContent.addAll(new SearchModule(Settings.EMPTY, false, Collections.emptyList()).getNamedXContents());
+        return new NamedXContentRegistry(namedXContent);
+    }
+
+    @Override
+    protected NamedWriteableRegistry getNamedWriteableRegistry() {
+        List<NamedWriteableRegistry.Entry> entries = new ArrayList<>();
+        entries.addAll(new MlInferenceNamedXContentProvider().getNamedWriteables());
+        return new NamedWriteableRegistry(entries);
+    }
+
+    public void testValidateWithNullDefinition() {
+        IllegalArgumentException ex = expectThrows(IllegalArgumentException.class, () -> TrainedModelConfig.builder().validate());
+        assertThat(ex.getMessage(), equalTo("[definition] must not be null."));
+    }
+
+    public void testValidateWithInvalidID() {
+        String modelId = "InvalidID-";
+        ElasticsearchException ex = expectThrows(ElasticsearchException.class,
+            () -> TrainedModelConfig.builder().setDefinition(randomFrom(TreeTests.createRandom())).setModelId(modelId).validate());
+        assertThat(ex.getMessage(), equalTo(Messages.getMessage(Messages.INVALID_ID, "model_id", modelId)));
+    }
+
+    public void testValidateWithLongID() {
+        String modelId = IntStream.range(0, 100).mapToObj(x -> "a").collect(Collectors.joining());
+        ElasticsearchException ex = expectThrows(ElasticsearchException.class,
+            () -> TrainedModelConfig.builder().setDefinition(randomFrom(TreeTests.createRandom())).setModelId(modelId).validate());
+        assertThat(ex.getMessage(), equalTo(Messages.getMessage(Messages.ID_TOO_LONG, "model_id", modelId, MlStrings.ID_LENGTH_LIMIT)));
+    }
+
+    public void testValidateWithIllegallyUserProvidedFields() {
+        String modelId = "simplemodel";
+        ElasticsearchException ex = expectThrows(ElasticsearchException.class,
+            () -> TrainedModelConfig.builder()
+                .setDefinition(randomFrom(TreeTests.createRandom()))
+                .setCreatedTime(Instant.now())
+                .setModelId(modelId).validate());
+        assertThat(ex.getMessage(), equalTo("illegal to set [created_time] at inference model creation"));
+
+        ex = expectThrows(ElasticsearchException.class,
+            () -> TrainedModelConfig.builder()
+                .setDefinition(randomFrom(TreeTests.createRandom()))
+                .setVersion(Version.CURRENT)
+                .setModelId(modelId).validate());
+        assertThat(ex.getMessage(), equalTo("illegal to set [version] at inference model creation"));
+
+        ex = expectThrows(ElasticsearchException.class,
+            () -> TrainedModelConfig.builder()
+                .setDefinition(randomFrom(TreeTests.createRandom()))
+                .setCreatedBy("ml_user")
+                .setModelId(modelId).validate());
+        assertThat(ex.getMessage(), equalTo("illegal to set [created_by] at inference model creation"));
+    }
+}

x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/ml/utils/NamedXContentObjectHelperTests.java

@@ -0,0 +1,101 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+package org.elasticsearch.xpack.core.ml.utils;
+
+import org.elasticsearch.client.ml.inference.NamedXContentObject;
+import org.elasticsearch.client.ml.inference.NamedXContentObjectHelper;
+import org.elasticsearch.common.ParseField;
+import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.NamedXContentRegistry;
+import org.elasticsearch.common.xcontent.ObjectParser;
+import org.elasticsearch.common.xcontent.ToXContent;
+import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.search.SearchModule;
+import org.elasticsearch.test.ESTestCase;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+import static org.hamcrest.Matchers.equalTo;
+
+public class NamedXContentObjectHelperTests extends ESTestCase {
+
+    static class NamedTestObject implements NamedXContentObject {
+
+        private String fieldValue;
+        public static final ObjectParser<NamedTestObject, Void> PARSER =
+            new ObjectParser<>("my_named_object", true, NamedTestObject::new);
+        static {
+            PARSER.declareString(NamedTestObject::setFieldValue, new ParseField("my_field"));
+        }
+
+        NamedTestObject() {
+
+        }
+
+        NamedTestObject(String value) {
+            this.fieldValue = value;
+        }
+
+        @Override
+        public String getName() {
+            return "my_named_object";
+        }
+
+        void setFieldValue(String value) {
+            this.fieldValue = value;
+        }
+
+        @Override
+        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+            builder.startObject();
+            if (fieldValue != null) {
+                builder.field("my_field", fieldValue);
+            }
+            builder.endObject();
+            return builder;
+        }
+    }
+
+    public void testSerializeInOrder() throws IOException {
+        String expected =
+            "{\"my_objects\":[{\"my_named_object\":{\"my_field\":\"value1\"}},{\"my_named_object\":{\"my_field\":\"value2\"}}]}";
+        try (XContentBuilder builder = XContentFactory.jsonBuilder()) {
+            builder.startObject();
+            List<NamedXContentObject> objects = Arrays.asList(new NamedTestObject("value1"), new NamedTestObject("value2"));
+            NamedXContentObjectHelper.writeNamedObjects(builder, ToXContent.EMPTY_PARAMS, true, "my_objects", objects);
+            builder.endObject();
+            assertThat(BytesReference.bytes(builder).utf8ToString(), equalTo(expected));
+        }
+    }
+
+    public void testSerialize() throws IOException {
+        String expected = "{\"my_objects\":{\"my_named_object\":{\"my_field\":\"value1\"},\"my_named_object\":{\"my_field\":\"value2\"}}}";
+        try (XContentBuilder builder = XContentFactory.jsonBuilder()) {
+            builder.startObject();
+            List<NamedXContentObject> objects = Arrays.asList(new NamedTestObject("value1"), new NamedTestObject("value2"));
+            NamedXContentObjectHelper.writeNamedObjects(builder, ToXContent.EMPTY_PARAMS, false, "my_objects", objects);
+            builder.endObject();
+            assertThat(BytesReference.bytes(builder).utf8ToString(), equalTo(expected));
+        }
+    }
+
+    @Override
+    protected NamedXContentRegistry xContentRegistry() {
+        List<NamedXContentRegistry.Entry> namedXContent = new ArrayList<>();
+        namedXContent.addAll(Collections.singletonList(new NamedXContentRegistry.Entry(NamedXContentObject.class,
+            new ParseField("my_named_object"),
+            (p, c) -> NamedTestObject.PARSER.apply(p, null))));
+        namedXContent.addAll(new SearchModule(Settings.EMPTY, false, Collections.emptyList()).getNamedXContents());
+        return new NamedXContentRegistry(namedXContent);
+    }
+
+}

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/MachineLearning.java

@@ -123,6 +123,7 @@ import org.elasticsearch.xpack.core.ml.action.ValidateJobConfigAction;
 import org.elasticsearch.xpack.core.ml.dataframe.analyses.MlDataFrameAnalysisNamedXContentProvider;
 import org.elasticsearch.xpack.core.ml.dataframe.evaluation.MlEvaluationNamedXContentProvider;
 import org.elasticsearch.xpack.core.ml.inference.MlInferenceNamedXContentProvider;
+import org.elasticsearch.xpack.core.ml.inference.persistence.InferenceIndexConstants;
 import org.elasticsearch.xpack.core.ml.job.persistence.AnomalyDetectorsIndex;
 import org.elasticsearch.xpack.core.ml.job.persistence.AnomalyDetectorsIndexFields;
 import org.elasticsearch.xpack.core.ml.job.persistence.ElasticsearchMappings;
@@ -198,6 +199,7 @@ import org.elasticsearch.xpack.ml.dataframe.process.MemoryUsageEstimationProcess
 import org.elasticsearch.xpack.ml.dataframe.process.results.MemoryUsageEstimationResult;
 import org.elasticsearch.xpack.ml.dataframe.process.NativeMemoryUsageEstimationProcessFactory;
 import org.elasticsearch.xpack.ml.dataframe.process.NativeAnalyticsProcessFactory;
+import org.elasticsearch.xpack.ml.inference.persistence.InferenceInternalIndex;
 import org.elasticsearch.xpack.ml.job.JobManager;
 import org.elasticsearch.xpack.ml.job.JobManagerHolder;
 import org.elasticsearch.xpack.ml.job.UpdateJobProcessNotifier;
@@ -906,6 +908,12 @@ public class MachineLearning extends Plugin implements ActionPlugin, AnalysisPlu
                 logger.error("Error loading the template for the " + AnomalyDetectorsIndex.jobResultsIndexPrefix() + " indices", e);
             }
 
+            try {
+                templates.put(InferenceIndexConstants.LATEST_INDEX_NAME, InferenceInternalIndex.getIndexTemplateMetaData());
+            } catch (IOException e) {
+                logger.error("Error loading the template for the " + InferenceIndexConstants.LATEST_INDEX_NAME + " index", e);
+            }
+
             return templates;
         };
     }
@@ -917,7 +925,8 @@ public class MachineLearning extends Plugin implements ActionPlugin, AnalysisPlu
                 AuditorField.NOTIFICATIONS_INDEX,
                 MlMetaIndex.INDEX_NAME,
                 AnomalyDetectorsIndexFields.STATE_INDEX_PREFIX,
-                AnomalyDetectorsIndex.jobResultsIndexPrefix());
+                AnomalyDetectorsIndex.jobResultsIndexPrefix(),
+                InferenceIndexConstants.LATEST_INDEX_NAME);
         for (String templateName : templateNames) {
             allPresent = allPresent && TemplateUtils.checkTemplateExistsAndVersionIsGTECurrentVersion(templateName, clusterState);
         }

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/inference/persistence/InferenceInternalIndex.java

@@ -0,0 +1,106 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+package org.elasticsearch.xpack.ml.inference.persistence;
+
+import org.elasticsearch.Version;
+import org.elasticsearch.cluster.metadata.IndexMetaData;
+import org.elasticsearch.cluster.metadata.IndexTemplateMetaData;
+import org.elasticsearch.common.Strings;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.xpack.core.ml.inference.TrainedModelConfig;
+
+import java.io.IOException;
+import java.util.Collections;
+
+import static org.elasticsearch.common.xcontent.XContentFactory.jsonBuilder;
+import static org.elasticsearch.index.mapper.MapperService.SINGLE_MAPPING_NAME;
+import static org.elasticsearch.xpack.core.ml.inference.persistence.InferenceIndexConstants.LATEST_INDEX_NAME;
+import static org.elasticsearch.xpack.core.ml.job.persistence.ElasticsearchMappings.DATE;
+import static org.elasticsearch.xpack.core.ml.job.persistence.ElasticsearchMappings.DYNAMIC;
+import static org.elasticsearch.xpack.core.ml.job.persistence.ElasticsearchMappings.ENABLED;
+import static org.elasticsearch.xpack.core.ml.job.persistence.ElasticsearchMappings.KEYWORD;
+import static org.elasticsearch.xpack.core.ml.job.persistence.ElasticsearchMappings.LONG;
+import static org.elasticsearch.xpack.core.ml.job.persistence.ElasticsearchMappings.PROPERTIES;
+import static org.elasticsearch.xpack.core.ml.job.persistence.ElasticsearchMappings.TEXT;
+import static org.elasticsearch.xpack.core.ml.job.persistence.ElasticsearchMappings.TYPE;
+import static org.elasticsearch.xpack.core.ml.job.persistence.ElasticsearchMappings.addMetaInformation;
+
+
+/**
+ * Changelog of internal index versions
+ *
+ * Please list changes, increase the version in {@link InferenceInternalIndex} if you are 1st in this release cycle
+ *
+ * version 1 (7.5): initial
+ */
+public final class InferenceInternalIndex {
+
+    private InferenceInternalIndex() {}
+
+    public static XContentBuilder mappings() throws IOException {
+        return configMapping(SINGLE_MAPPING_NAME);
+    }
+
+    public static IndexTemplateMetaData getIndexTemplateMetaData() throws IOException {
+        IndexTemplateMetaData inferenceTemplate = IndexTemplateMetaData.builder(LATEST_INDEX_NAME)
+            .patterns(Collections.singletonList(LATEST_INDEX_NAME))
+            .version(Version.CURRENT.id)
+            .settings(Settings.builder()
+                // the configurations are expected to be small
+                .put(IndexMetaData.SETTING_NUMBER_OF_SHARDS, 1)
+                .put(IndexMetaData.SETTING_AUTO_EXPAND_REPLICAS, "0-1"))
+            .putMapping(SINGLE_MAPPING_NAME, Strings.toString(mappings()))
+            .build();
+        return inferenceTemplate;
+    }
+
+    public static XContentBuilder configMapping(String mappingType) throws IOException {
+        XContentBuilder builder = jsonBuilder();
+        builder.startObject();
+        builder.startObject(mappingType);
+        addMetaInformation(builder);
+
+        // do not allow anything outside of the defined schema
+        builder.field(DYNAMIC, "false");
+
+        builder.startObject(PROPERTIES);
+        addInferenceDocFields(builder);
+        return builder.endObject()
+            .endObject()
+            .endObject();
+    }
+
+    private static void addInferenceDocFields(XContentBuilder builder) throws IOException {
+        builder.startObject(TrainedModelConfig.MODEL_ID.getPreferredName())
+            .field(TYPE, KEYWORD)
+            .endObject()
+            .startObject(TrainedModelConfig.CREATED_BY.getPreferredName())
+            .field(TYPE, KEYWORD)
+            .endObject()
+            .startObject(TrainedModelConfig.VERSION.getPreferredName())
+            .field(TYPE, KEYWORD)
+            .endObject()
+            .startObject(TrainedModelConfig.DESCRIPTION.getPreferredName())
+            .field(TYPE, TEXT)
+            .endObject()
+            .startObject(TrainedModelConfig.CREATED_TIME.getPreferredName())
+            .field(TYPE, DATE)
+            .endObject()
+            .startObject(TrainedModelConfig.MODEL_VERSION.getPreferredName())
+            .field(TYPE, LONG)
+            .endObject()
+            .startObject(TrainedModelConfig.DEFINITION.getPreferredName())
+            .field(ENABLED, false)
+            .endObject()
+            .startObject(TrainedModelConfig.MODEL_TYPE.getPreferredName())
+            .field(TYPE, KEYWORD)
+            .endObject()
+            .startObject(TrainedModelConfig.METADATA.getPreferredName())
+            .field(ENABLED, false)
+            .endObject();
+    }
+}

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/inference/persistence/TrainedModelProvider.java

@@ -0,0 +1,134 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+package org.elasticsearch.xpack.ml.inference.persistence;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.elasticsearch.ElasticsearchParseException;
+import org.elasticsearch.ElasticsearchStatusException;
+import org.elasticsearch.ResourceAlreadyExistsException;
+import org.elasticsearch.ResourceNotFoundException;
+import org.elasticsearch.action.ActionListener;
+import org.elasticsearch.action.DocWriteRequest;
+import org.elasticsearch.action.index.IndexAction;
+import org.elasticsearch.action.index.IndexRequest;
+import org.elasticsearch.action.search.SearchAction;
+import org.elasticsearch.action.search.SearchRequest;
+import org.elasticsearch.action.support.WriteRequest;
+import org.elasticsearch.client.Client;
+import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.xcontent.LoggingDeprecationHandler;
+import org.elasticsearch.common.xcontent.NamedXContentRegistry;
+import org.elasticsearch.common.xcontent.ToXContent;
+import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.common.xcontent.XContentType;
+import org.elasticsearch.index.engine.VersionConflictEngineException;
+import org.elasticsearch.index.query.QueryBuilder;
+import org.elasticsearch.index.query.QueryBuilders;
+import org.elasticsearch.rest.RestStatus;
+import org.elasticsearch.search.sort.SortOrder;
+import org.elasticsearch.xpack.core.ml.inference.TrainedModelConfig;
+import org.elasticsearch.xpack.core.ml.inference.persistence.InferenceIndexConstants;
+import org.elasticsearch.xpack.core.ml.job.messages.Messages;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+import static org.elasticsearch.xpack.core.ClientHelper.ML_ORIGIN;
+import static org.elasticsearch.xpack.core.ClientHelper.executeAsyncWithOrigin;
+
+public class TrainedModelProvider {
+
+    private static final Logger logger = LogManager.getLogger(TrainedModelProvider.class);
+    private final Client client;
+    private final NamedXContentRegistry xContentRegistry;
+
+    public TrainedModelProvider(Client client, NamedXContentRegistry xContentRegistry) {
+        this.client = client;
+        this.xContentRegistry = xContentRegistry;
+    }
+
+    public void storeTrainedModel(TrainedModelConfig trainedModelConfig, ActionListener<Boolean> listener) {
+        try (XContentBuilder builder = XContentFactory.jsonBuilder()) {
+            XContentBuilder source = trainedModelConfig.toXContent(builder, ToXContent.EMPTY_PARAMS);
+
+            IndexRequest indexRequest = new IndexRequest(InferenceIndexConstants.LATEST_INDEX_NAME)
+                .opType(DocWriteRequest.OpType.CREATE)
+                .setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE)
+                .id(TrainedModelConfig.documentId(trainedModelConfig.getModelId(), trainedModelConfig.getModelVersion()))
+                .source(source);
+            executeAsyncWithOrigin(client, ML_ORIGIN, IndexAction.INSTANCE, indexRequest,
+                ActionListener.wrap(
+                    r -> listener.onResponse(true),
+                    e -> {
+                        logger.error(
+                            new ParameterizedMessage("[{}][{}] failed to store trained model for inference",
+                                trainedModelConfig.getModelId(),
+                                trainedModelConfig.getModelVersion()),
+                            e);
+                        if (e instanceof VersionConflictEngineException) {
+                            listener.onFailure(new ResourceAlreadyExistsException(
+                                Messages.getMessage(Messages.INFERENCE_TRAINED_MODEL_EXISTS,
+                                    trainedModelConfig.getModelId(), trainedModelConfig.getModelVersion())));
+                        } else {
+                            listener.onFailure(
+                                new ElasticsearchStatusException(Messages.INFERENCE_FAILED_TO_STORE_MODEL,
+                                    RestStatus.INTERNAL_SERVER_ERROR,
+                                    e,
+                                    trainedModelConfig.getModelId()));
+                        }
+                    }));
+        } catch (IOException e) {
+            // not expected to happen but for the sake of completeness
+            listener.onFailure(new ElasticsearchParseException(
+                Messages.getMessage(Messages.INFERENCE_FAILED_TO_SERIALIZE_MODEL, trainedModelConfig.getModelId()),
+                e));
+        }
+    }
+
+    public void getTrainedModel(String modelId, long modelVersion, ActionListener<TrainedModelConfig> listener) {
+        QueryBuilder queryBuilder = QueryBuilders.constantScoreQuery(QueryBuilders
+            .idsQuery()
+            .addIds(TrainedModelConfig.documentId(modelId, modelVersion)));
+        SearchRequest searchRequest = client.prepareSearch(InferenceIndexConstants.INDEX_PATTERN)
+            .setQuery(queryBuilder)
+            // use sort to get the last
+            .addSort("_index", SortOrder.DESC)
+            .setSize(1)
+            .request();
+
+        executeAsyncWithOrigin(client, ML_ORIGIN, SearchAction.INSTANCE, searchRequest,
+            ActionListener.wrap(
+                searchResponse -> {
+                    if (searchResponse.getHits().getHits().length == 0) {
+                        listener.onFailure(new ResourceNotFoundException(
+                            Messages.getMessage(Messages.INFERENCE_NOT_FOUND, modelId, modelVersion)));
+                        return;
+                    }
+                    BytesReference source = searchResponse.getHits().getHits()[0].getSourceRef();
+                    parseInferenceDocLenientlyFromSource(source, modelId, modelVersion, listener);
+                },
+                listener::onFailure));
+    }
+
+
+    private void parseInferenceDocLenientlyFromSource(BytesReference source,
+                                                      String modelId,
+                                                      long modelVersion,
+                                                      ActionListener<TrainedModelConfig> modelListener) {
+        try (InputStream stream = source.streamInput();
+             XContentParser parser = XContentFactory.xContent(XContentType.JSON)
+                 .createParser(xContentRegistry, LoggingDeprecationHandler.INSTANCE, stream)) {
+            modelListener.onResponse(TrainedModelConfig.fromXContent(parser, true).build());
+        } catch (Exception e) {
+            logger.error(new ParameterizedMessage("[{}][{}] failed to parse model", modelId, modelVersion), e);
+            modelListener.onFailure(e);
+        }
+    }
+}

x-pack/plugin/ml/src/test/java/org/elasticsearch/xpack/ml/integration/TrainedModelProviderIT.java

@@ -0,0 +1,113 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+package org.elasticsearch.xpack.ml.integration;
+
+import org.elasticsearch.Version;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.NamedXContentRegistry;
+import org.elasticsearch.search.SearchModule;
+import org.elasticsearch.xpack.core.ml.inference.MlInferenceNamedXContentProvider;
+import org.elasticsearch.xpack.core.ml.inference.TrainedModelConfig;
+import org.elasticsearch.xpack.core.ml.inference.trainedmodel.tree.TreeTests;
+import org.elasticsearch.xpack.core.ml.job.messages.Messages;
+import org.elasticsearch.xpack.ml.MlSingleNodeTestCase;
+import org.elasticsearch.xpack.ml.inference.persistence.TrainedModelProvider;
+import org.junit.Before;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicReference;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.not;
+import static org.hamcrest.Matchers.nullValue;
+
+public class TrainedModelProviderIT extends MlSingleNodeTestCase {
+
+    private TrainedModelProvider trainedModelProvider;
+
+    @Before
+    public void createComponents() throws Exception {
+        trainedModelProvider = new TrainedModelProvider(client(), xContentRegistry());
+        waitForMlTemplates();
+    }
+
+    public void testPutTrainedModelConfig() throws Exception {
+        String modelId = "test-put-trained-model-config";
+        TrainedModelConfig config = buildTrainedModelConfig(modelId, 0);
+        AtomicReference<Boolean> putConfigHolder = new AtomicReference<>();
+        AtomicReference<Exception> exceptionHolder = new AtomicReference<>();
+
+        blockingCall(listener -> trainedModelProvider.storeTrainedModel(config, listener), putConfigHolder, exceptionHolder);
+        assertThat(putConfigHolder.get(), is(true));
+        assertThat(exceptionHolder.get(), is(nullValue()));
+    }
+
+    public void testPutTrainedModelConfigThatAlreadyExists() throws Exception {
+        String modelId = "test-put-trained-model-config-exists";
+        TrainedModelConfig config = buildTrainedModelConfig(modelId, 0);
+        AtomicReference<Boolean> putConfigHolder = new AtomicReference<>();
+        AtomicReference<Exception> exceptionHolder = new AtomicReference<>();
+
+        blockingCall(listener -> trainedModelProvider.storeTrainedModel(config, listener), putConfigHolder, exceptionHolder);
+        assertThat(putConfigHolder.get(), is(true));
+        assertThat(exceptionHolder.get(), is(nullValue()));
+
+        blockingCall(listener -> trainedModelProvider.storeTrainedModel(config, listener), putConfigHolder, exceptionHolder);
+        assertThat(exceptionHolder.get(), is(not(nullValue())));
+        assertThat(exceptionHolder.get().getMessage(),
+            equalTo(Messages.getMessage(Messages.INFERENCE_TRAINED_MODEL_EXISTS, modelId, 0)));
+    }
+
+    public void testGetTrainedModelConfig() throws Exception {
+        String modelId = "test-get-trained-model-config";
+        TrainedModelConfig config = buildTrainedModelConfig(modelId, 0);
+        AtomicReference<Boolean> putConfigHolder = new AtomicReference<>();
+        AtomicReference<Exception> exceptionHolder = new AtomicReference<>();
+
+        blockingCall(listener -> trainedModelProvider.storeTrainedModel(config, listener), putConfigHolder, exceptionHolder);
+        assertThat(putConfigHolder.get(), is(true));
+        assertThat(exceptionHolder.get(), is(nullValue()));
+
+        AtomicReference<TrainedModelConfig> getConfigHolder = new AtomicReference<>();
+        blockingCall(listener -> trainedModelProvider.getTrainedModel(modelId, 0, listener), getConfigHolder, exceptionHolder);
+        assertThat(getConfigHolder.get(), is(not(nullValue())));
+        assertThat(getConfigHolder.get(), equalTo(config));
+    }
+
+    public void testGetMissingTrainingModelConfig() throws Exception {
+        String modelId = "test-get-missing-trained-model-config";
+        AtomicReference<TrainedModelConfig> getConfigHolder = new AtomicReference<>();
+        AtomicReference<Exception> exceptionHolder = new AtomicReference<>();
+        blockingCall(listener -> trainedModelProvider.getTrainedModel(modelId, 0, listener), getConfigHolder, exceptionHolder);
+        assertThat(exceptionHolder.get(), is(not(nullValue())));
+        assertThat(exceptionHolder.get().getMessage(),
+            equalTo(Messages.getMessage(Messages.INFERENCE_NOT_FOUND, modelId, 0)));
+    }
+
+    private static TrainedModelConfig buildTrainedModelConfig(String modelId, long modelVersion) {
+        return TrainedModelConfig.builder()
+            .setCreatedBy("ml_test")
+            .setDefinition(TreeTests.createRandom())
+            .setDescription("trained model config for test")
+            .setModelId(modelId)
+            .setModelType("binary_decision_tree")
+            .setModelVersion(modelVersion)
+            .build(Version.CURRENT);
+    }
+
+    @Override
+    public NamedXContentRegistry xContentRegistry() {
+        List<NamedXContentRegistry.Entry> namedXContent = new ArrayList<>();
+        namedXContent.addAll(new MlInferenceNamedXContentProvider().getNamedXContentParsers());
+        namedXContent.addAll(new SearchModule(Settings.EMPTY, false, Collections.emptyList()).getNamedXContents());
+        return new NamedXContentRegistry(namedXContent);
+
+    }
+
+}