KAFKA-16814 KRaft broker cannot startup when partition.metadata is …

…missing (apache#16165)

When starting up kafka logManager, we'll check stray replicas to avoid some corner cases. But this check might cause broker unable to startup if partition.metadata is missing because when startup kafka, we load log from file, and the topicId of the log is coming from partition.metadata file. So, if partition.metadata is missing, the topicId will be None, and the LogManager#isStrayKraftReplica will fail with no topicID error.

The partition.metadata missing could be some storage failure, or another possible path is unclean shutdown after topic is created in the replica, but before data is flushed into partition.metadata file. This is possible because we do the flush in async way here.

When finding a log without topicID, we should treat it as a stray log and then delete it.

Reviewers: Luke Chen <showuon@gmail.com>, Gaurav Narula <gaurav_narula2@apple.com>

core/src/main/scala/kafka/log/LogManager.scala

@@ -1604,11 +1604,16 @@ object LogManager {
    newTopicsImage: TopicsImage,
    log: UnifiedLog
   ): Boolean = {
-    val topicId = log.topicId.getOrElse {
-      throw new RuntimeException(s"The log dir $log does not have a topic ID, " +
-        "which is not allowed when running in KRaft mode.")
+    if (log.topicId.isEmpty) {
+      // Missing topic ID could result from storage failure or unclean shutdown after topic creation but before flushing
+      // data to the `partition.metadata` file. And before appending data to the log, the `partition.metadata` is always
+      // flushed to disk. So if the topic ID is missing, it mostly means no data was appended, and we can treat this as
+      // a stray log.
+      info(s"The topicId does not exist in $log, treat it as a stray log")
+      return true
     }
 
+    val topicId = log.topicId.get
     val partitionId = log.topicPartition.partition()
     Option(newTopicsImage.getPartition(topicId, partitionId)) match {
       case Some(partition) =>

core/src/test/java/kafka/server/LogManagerIntegrationTest.java

@@ -0,0 +1,137 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF 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 kafka.server;
+
+import kafka.test.ClusterInstance;
+import kafka.test.annotation.ClusterTest;
+import kafka.test.annotation.Type;
+import kafka.test.junit.ClusterTestExtensions;
+import kafka.test.junit.RaftClusterInvocationContext;
+import org.apache.kafka.clients.admin.Admin;
+import org.apache.kafka.clients.admin.NewTopic;
+import org.apache.kafka.clients.consumer.Consumer;
+import org.apache.kafka.clients.consumer.ConsumerConfig;
+import org.apache.kafka.clients.consumer.ConsumerRecord;
+import org.apache.kafka.clients.consumer.ConsumerRecords;
+import org.apache.kafka.clients.consumer.KafkaConsumer;
+import org.apache.kafka.clients.producer.KafkaProducer;
+import org.apache.kafka.clients.producer.Producer;
+import org.apache.kafka.clients.producer.ProducerConfig;
+import org.apache.kafka.clients.producer.ProducerRecord;
+import org.apache.kafka.common.TopicPartition;
+import org.apache.kafka.common.TopicPartitionInfo;
+import org.apache.kafka.common.serialization.StringDeserializer;
+import org.apache.kafka.common.serialization.StringSerializer;
+import org.apache.kafka.storage.internals.checkpoint.PartitionMetadataFile;
+import org.apache.kafka.test.TestUtils;
+import org.junit.jupiter.api.Tag;
+import org.junit.jupiter.api.extension.ExtendWith;
+
+import java.io.IOException;
+import java.time.Duration;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.UUID;
+import java.util.concurrent.ExecutionException;
+
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+@ExtendWith(value = ClusterTestExtensions.class)
+@Tag("integration")
+public class LogManagerIntegrationTest {
+    private final ClusterInstance cluster;
+
+    public LogManagerIntegrationTest(ClusterInstance cluster) {
+        this.cluster = cluster;
+    }
+
+    @ClusterTest(types = {Type.KRAFT, Type.CO_KRAFT}, brokers = 3)
+    public void testRestartBrokerNoErrorIfMissingPartitionMetadata() throws IOException, ExecutionException, InterruptedException {
+        RaftClusterInvocationContext.RaftClusterInstance raftInstance =
+                (RaftClusterInvocationContext.RaftClusterInstance) cluster;
+
+        try (Admin admin = cluster.createAdminClient()) {
+            admin.createTopics(Collections.singletonList(new NewTopic("foo", 1, (short) 3))).all().get();
+        }
+        cluster.waitForTopic("foo", 1);
+
+        Optional<PartitionMetadataFile> partitionMetadataFile = Optional.ofNullable(
+                raftInstance.getUnderlying().brokers().get(0).logManager()
+                        .getLog(new TopicPartition("foo", 0), false).get()
+                        .partitionMetadataFile().getOrElse(null));
+        assertTrue(partitionMetadataFile.isPresent());
+
+        raftInstance.getUnderlying().brokers().get(0).shutdown();
+        try (Admin admin = cluster.createAdminClient()) {
+            TestUtils.waitForCondition(() -> {
+                List<TopicPartitionInfo> partitionInfos = admin.describeTopics(Collections.singletonList("foo"))
+                        .topicNameValues().get("foo").get().partitions();
+                return partitionInfos.get(0).isr().size() == 2;
+            }, "isr size is not shrink to 2");
+        }
+
+        // delete partition.metadata file here to simulate the scenario that partition.metadata not flush to disk yet
+        partitionMetadataFile.get().delete();
+        assertFalse(partitionMetadataFile.get().exists());
+        raftInstance.getUnderlying().brokers().get(0).startup();
+        // make sure there is no error during load logs
+        assertDoesNotThrow(() -> raftInstance.getUnderlying().fatalFaultHandler().maybeRethrowFirstException());
+        try (Admin admin = cluster.createAdminClient()) {
+            TestUtils.waitForCondition(() -> {
+                List<TopicPartitionInfo> partitionInfos = admin.describeTopics(Collections.singletonList("foo"))
+                        .topicNameValues().get("foo").get().partitions();
+                return partitionInfos.get(0).isr().size() == 3;
+            }, "isr size is not expand to 3");
+        }
+
+        // make sure topic still work fine
+        Map<String, Object> producerConfigs = new HashMap<>();
+        producerConfigs.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, cluster.bootstrapServers());
+        producerConfigs.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
+        producerConfigs.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
+
+        try (Producer<String, String> producer = new KafkaProducer<>(producerConfigs)) {
+            producer.send(new ProducerRecord<>("foo", 0, null, "bar")).get();
+            producer.flush();
+        }
+
+        Map<String, Object> consumerConfigs = new HashMap<>();
+        consumerConfigs.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, cluster.bootstrapServers());
+        consumerConfigs.put(ConsumerConfig.GROUP_ID_CONFIG, UUID.randomUUID().toString());
+        consumerConfigs.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
+        consumerConfigs.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
+
+        try (Consumer<String, String> consumer = new KafkaConsumer<>(consumerConfigs)) {
+            consumer.assign(Collections.singletonList(new TopicPartition("foo", 0)));
+            consumer.seekToBeginning(Collections.singletonList(new TopicPartition("foo", 0)));
+            List<String> values = new ArrayList<>();
+            ConsumerRecords<String, String> records = consumer.poll(Duration.ofMinutes(1));
+            for (ConsumerRecord<String, String> record : records) {
+                values.add(record.value());
+            }
+            assertEquals(1, values.size());
+            assertEquals("bar", values.get(0));
+        }
+    }
+}

core/src/test/scala/unit/kafka/log/LogManagerTest.scala

@@ -1286,6 +1286,13 @@ class LogManagerTest {
     onDisk.foreach(log => assertEquals(expectedStrays.contains(log.topicPartition), LogManager.isStrayKraftReplica(0, image, log)))
   }
 
+  @Test
+  def testIsStrayKraftMissingTopicId(): Unit = {
+    val log = Mockito.mock(classOf[UnifiedLog])
+    Mockito.when(log.topicId).thenReturn(Option.empty)
+    assertTrue(LogManager.isStrayKraftReplica(0, topicsImage(Seq()), log))
+  }
+
   @Test
   def testFindStrayReplicasInEmptyLAIR(): Unit = {
     val onDisk = Seq(foo0, foo1, bar0, bar1, baz0, baz1, baz2, quux0)