diff --git a/docker/Dockerfile b/docker/Dockerfile
index 37a9746d..51dcbca5 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -24,7 +24,7 @@ RUN cd /code && mkdir -p /zipkin-storage-kafka && \
     jar xf *.jar && \
     rm *.jar
 
-FROM openzipkin/zipkin:2.18.3
+FROM openzipkin/zipkin:2.19.1
 MAINTAINER Zipkin "https://zipkin.io/"
 
 COPY --from=0 /zipkin-storage-kafka/ /zipkin/lib/
diff --git a/module/src/main/java/zipkin2/module/storage/kafka/ZipkinKafkaStorageModule.java b/module/src/main/java/zipkin2/module/storage/kafka/ZipkinKafkaStorageModule.java
index 16bfd8af..3ab4a7a5 100644
--- a/module/src/main/java/zipkin2/module/storage/kafka/ZipkinKafkaStorageModule.java
+++ b/module/src/main/java/zipkin2/module/storage/kafka/ZipkinKafkaStorageModule.java
@@ -44,8 +44,8 @@ class ZipkinKafkaStorageModule {
         .build();
   }
 
-  // TODO: to be changed when >zipkin 2.18.4 #61
-  // @Bean public Consumer<ServerBuilder> storageHttpService(StorageComponent storage) {
+  //TODO replace when Armeria supports Consumer<ServerBuilder> #61
+  //@Bean public Consumer<ServerBuilder> storageHttpService(StorageComponent storage) {
   @Bean public ArmeriaServerConfigurator storageHttpService(StorageComponent storage) {
     return sb -> sb.annotatedService(HTTP_PATH_PREFIX, ((KafkaStorage) storage).httpService());
   }
diff --git a/pom.xml b/pom.xml
index a0c9be2b..d95a4534 100644
--- a/pom.xml
+++ b/pom.xml
@@ -50,11 +50,10 @@
     <main.basedir>${project.basedir}</main.basedir>
 
     <!-- groupId overrinds allow testing feature branches with jitpack -->
-    <!-- TODO: update armeria to 0.95 when zipkin >2.18.3 -->
     <zipkin.groupId>io.zipkin.zipkin2</zipkin.groupId>
-    <zipkin.version>2.18.3</zipkin.version>
+    <zipkin.version>2.19.1</zipkin.version>
     <armeria.groupId>com.linecorp.armeria</armeria.groupId>
-    <armeria.version>0.94.0</armeria.version>
+    <armeria.version>0.95.0</armeria.version>
     <spring-boot.version>2.2.0.RELEASE</spring-boot.version>
 
     <kafka.version>2.3.1</kafka.version>
@@ -101,7 +100,8 @@
   <scm>
     <url>https://github.com/openzipkin-contrib/zipkin-storage-kafka</url>
     <connection>scm:git:https://github.com/openzipkin-contrib/zipkin-storage-kafka.git</connection>
-    <developerConnection>scm:git:https://github.com/openzipkin-contrib/zipkin-storage-kafka.git
+    <developerConnection>
+      scm:git:https://github.com/openzipkin-contrib/zipkin-storage-kafka.git
     </developerConnection>
     <tag>HEAD</tag>
   </scm>
diff --git a/storage/src/main/java/zipkin2/storage/kafka/KafkaSpanConsumer.java b/storage/src/main/java/zipkin2/storage/kafka/KafkaSpanConsumer.java
index cb849534..8dfccafb 100644
--- a/storage/src/main/java/zipkin2/storage/kafka/KafkaSpanConsumer.java
+++ b/storage/src/main/java/zipkin2/storage/kafka/KafkaSpanConsumer.java
@@ -35,9 +35,7 @@
  * processing of spans as part of a trace.
  */
 final class KafkaSpanConsumer implements SpanConsumer {
-  // Topic names
   final String spansTopicName;
-  // Kafka producers
   final Producer<String, byte[]> producer;
 
   KafkaSpanConsumer(KafkaStorage storage) {
@@ -69,7 +67,8 @@ static class KafkaProducerCall extends Call.Base<Void> {
         Producer<String, byte[]> kafkaProducer,
         String topic,
         String key,
-        byte[] value) {
+        byte[] value
+    ) {
       this.kafkaProducer = kafkaProducer;
       this.topic = topic;
       this.key = key;
@@ -80,7 +79,8 @@ static Call<Void> create(
         Producer<String, byte[]> producer,
         String topic,
         String key,
-        byte[] value) {
+        byte[] value
+    ) {
       return new KafkaProducerCall(producer, topic, key, value);
     }
 
diff --git a/storage/src/main/java/zipkin2/storage/kafka/KafkaStorage.java b/storage/src/main/java/zipkin2/storage/kafka/KafkaStorage.java
index f6b588e6..02c3ca4e 100644
--- a/storage/src/main/java/zipkin2/storage/kafka/KafkaStorage.java
+++ b/storage/src/main/java/zipkin2/storage/kafka/KafkaStorage.java
@@ -60,7 +60,7 @@ public static KafkaStorageBuilder newBuilder() {
     return new KafkaStorageBuilder();
   }
 
-  // Kafka Storage modes
+  // Kafka Storage flags
   final boolean partitioningEnabled;
   final boolean aggregationEnabled;
   final boolean traceByIdQueryEnabled;
@@ -107,7 +107,6 @@ public static KafkaStorageBuilder newBuilder() {
     this.storageSpansTopic = builder.traceStorage.spansTopic;
     this.storageDependencyTopic = builder.dependencyStorage.dependencyTopic;
     // Storage directories
-    //this.storageDir = builder.storageStateDir;
     this.minTracesStored = builder.traceStorage.minTracesStored;
     this.httpBaseUrl = builder.httpBaseUrl;
     this.hostname = builder.hostname;
@@ -213,18 +212,10 @@ void checkResources() {
   void doClose() {
     try {
       if (adminClient != null) adminClient.close(Duration.ofSeconds(1));
-      if (producer != null) {
-        producer.close(Duration.ofSeconds(1));
-      }
-      if (traceStoreStream != null) {
-        traceStoreStream.close(Duration.ofSeconds(1));
-      }
-      if (dependencyStoreStream != null) {
-        dependencyStoreStream.close(Duration.ofSeconds(1));
-      }
-      if (aggregationStream != null) {
-        aggregationStream.close(Duration.ofSeconds(1));
-      }
+      if (producer != null) producer.close(Duration.ofSeconds(1));
+      if (traceStoreStream != null) traceStoreStream.close(Duration.ofSeconds(1));
+      if (dependencyStoreStream != null) dependencyStoreStream.close(Duration.ofSeconds(1));
+      if (aggregationStream != null) aggregationStream.close(Duration.ofSeconds(1));
       if (server != null) server.close();
     } catch (Exception | Error e) {
       LOG.debug("error closing client {}", e.getMessage(), e);
@@ -234,9 +225,7 @@ void doClose() {
   Producer<String, byte[]> getProducer() {
     if (producer == null) {
       synchronized (this) {
-        if (producer == null) {
-          producer = new KafkaProducer<>(producerConfig);
-        }
+        if (producer == null) producer = new KafkaProducer<>(producerConfig);
       }
     }
     return producer;
@@ -245,9 +234,7 @@ Producer<String, byte[]> getProducer() {
   AdminClient getAdminClient() {
     if (adminClient == null) {
       synchronized (this) {
-        if (adminClient == null) {
-          adminClient = AdminClient.create(adminConfig);
-        }
+        if (adminClient == null) adminClient = AdminClient.create(adminConfig);
       }
     }
     return adminClient;
@@ -260,7 +247,7 @@ KafkaStreams getTraceStorageStream() {
           try {
             traceStoreStream = new KafkaStreams(traceStoreTopology, traceStoreStreamConfig);
             traceStoreStream.start();
-            LOG.info("Trace storage topology: {}", traceStoreTopology.describe());
+            LOG.info("Trace storage topology:\n{}", traceStoreTopology.describe());
           } catch (Exception e) {
             LOG.debug("Error starting trace storage process", e);
             traceStoreStream = null;
@@ -279,7 +266,7 @@ KafkaStreams getDependencyStorageStream() {
             dependencyStoreStream =
                 new KafkaStreams(dependencyStoreTopology, dependencyStoreStreamConfig);
             dependencyStoreStream.start();
-            LOG.info("Dependency storage topology: {}", dependencyStoreTopology.describe());
+            LOG.info("Dependency storage topology:\n{}", dependencyStoreTopology.describe());
           } catch (Exception e) {
             LOG.debug("Error starting dependency storage", e);
             dependencyStoreStream = null;
@@ -297,7 +284,7 @@ KafkaStreams getAggregationStream() {
           try {
             aggregationStream = new KafkaStreams(aggregationTopology, aggregationStreamConfig);
             aggregationStream.start();
-            LOG.info("Aggregation topology: {}", aggregationTopology.describe());
+            LOG.info("Aggregation topology:\n{}", aggregationTopology.describe());
           } catch (Exception e) {
             LOG.debug("Error loading aggregation process", e);
             aggregationStream = null;
diff --git a/storage/src/main/java/zipkin2/storage/kafka/KafkaStorageBuilder.java b/storage/src/main/java/zipkin2/storage/kafka/KafkaStorageBuilder.java
index 1b9d2097..50372f62 100644
--- a/storage/src/main/java/zipkin2/storage/kafka/KafkaStorageBuilder.java
+++ b/storage/src/main/java/zipkin2/storage/kafka/KafkaStorageBuilder.java
@@ -114,12 +114,12 @@ public final KafkaStorageBuilder overrides(Map<String, ?> overrides) {
     return this;
   }
 
-  public KafkaStorageBuilder spanPartitioningBuilder(SpanPartitioningBuilder builder) {
-    if (builder == null) throw new NullPointerException("builder == null");
-    this.spanPartitioning = builder;
-    return this;
-  }
-
+  /**
+   * Use this hostname to locate zipkin server between each other when forming a cluster.
+   * <p>
+   * When running multiple instances server local IP might not be the same as the external IP. e.g.
+   * Kubernetes Pod IP not been accessible from other Pods, and Service IPs that are accessible.
+   */
   public KafkaStorageBuilder hostname(String hostname) {
     if (hostname == null) throw new NullPointerException("hostname == null");
     this.hostname = hostname;
@@ -128,6 +128,9 @@ public KafkaStorageBuilder hostname(String hostname) {
     return this;
   }
 
+  /**
+   * Same port as Zipkin Server. To be changed only when Zipkin Server port is changed.
+   */
   public KafkaStorageBuilder serverPort(int serverPort) {
     if (serverPort <= 0) throw new IllegalArgumentException("serverPort <= 0");
     this.serverPort = serverPort;
@@ -136,6 +139,12 @@ public KafkaStorageBuilder serverPort(int serverPort) {
     return this;
   }
 
+  public KafkaStorageBuilder spanPartitioningBuilder(SpanPartitioningBuilder builder) {
+    if (builder == null) throw new NullPointerException("builder == null");
+    this.spanPartitioning = builder;
+    return this;
+  }
+
   public KafkaStorageBuilder spanAggregationBuilder(SpanAggregationBuilder builder) {
     if (builder == null) throw new NullPointerException("builder == null");
     this.spanAggregation = builder;
diff --git a/storage/src/main/java/zipkin2/storage/kafka/KafkaStorageHttpService.java b/storage/src/main/java/zipkin2/storage/kafka/KafkaStorageHttpService.java
index 4437ac98..3eb5df54 100644
--- a/storage/src/main/java/zipkin2/storage/kafka/KafkaStorageHttpService.java
+++ b/storage/src/main/java/zipkin2/storage/kafka/KafkaStorageHttpService.java
@@ -79,7 +79,8 @@ final class KafkaStorageHttpService {
   @Get("/dependencies")
   public AggregatedHttpResponse getDependencies(
       @Param("endTs") long endTs,
-      @Param("lookback") long lookback) {
+      @Param("lookback") long lookback
+  ) {
     try {
       if (!storage.dependencyQueryEnabled) return AggregatedHttpResponse.of(HttpStatus.NOT_FOUND);
       ReadOnlyWindowStore<Long, DependencyLink> store =
@@ -165,7 +166,8 @@ public AggregatedHttpResponse getTraces(
       @Param("maxDuration") Optional<Long> maxDuration,
       @Param("endTs") Optional<Long> endTs,
       @Default("86400000") @Param("lookback") Long lookback,
-      @Default("10") @Param("limit") int limit) {
+      @Default("10") @Param("limit") int limit
+  ) {
     try {
       if (!storage.traceSearchEnabled) return AggregatedHttpResponse.of(HttpStatus.NOT_FOUND);
       QueryRequest request =
@@ -223,7 +225,8 @@ void addResults(
       ReadOnlyKeyValueStore<String, List<Span>> tracesStore,
       List<List<Span>> traces,
       List<String> traceIds,
-      KeyValueIterator<Long, Set<String>> spanIds) {
+      KeyValueIterator<Long, Set<String>> spanIds
+  ) {
     spanIds.forEachRemaining(keyValue -> {
       for (String traceId : keyValue.value) {
         if (!traceIds.contains(traceId)) {
diff --git a/storage/src/main/java/zipkin2/storage/kafka/streams/DependencyStorageTopology.java b/storage/src/main/java/zipkin2/storage/kafka/streams/DependencyStorageTopology.java
index b3527fbd..72b7ee19 100644
--- a/storage/src/main/java/zipkin2/storage/kafka/streams/DependencyStorageTopology.java
+++ b/storage/src/main/java/zipkin2/storage/kafka/streams/DependencyStorageTopology.java
@@ -49,7 +49,8 @@ public DependencyStorageTopology(
       String dependencyTopic,
       Duration dependencyTtl,
       Duration dependencyWindowSize,
-      boolean dependencyQueryEnabled) {
+      boolean dependencyQueryEnabled
+  ) {
     this.dependencyTopic = dependencyTopic;
     this.dependencyTtl = dependencyTtl;
     this.dependencyWindowSize = dependencyWindowSize;
diff --git a/storage/src/main/java/zipkin2/storage/kafka/streams/SpanAggregationTopology.java b/storage/src/main/java/zipkin2/storage/kafka/streams/SpanAggregationTopology.java
index a3be8506..7cafa94b 100644
--- a/storage/src/main/java/zipkin2/storage/kafka/streams/SpanAggregationTopology.java
+++ b/storage/src/main/java/zipkin2/storage/kafka/streams/SpanAggregationTopology.java
@@ -60,7 +60,8 @@ public SpanAggregationTopology(
       String traceTopic,
       String dependencyTopic,
       Duration traceTimeout,
-      boolean aggregationEnabled) {
+      boolean aggregationEnabled
+  ) {
     this.spansTopic = spansTopic;
     this.traceTopic = traceTopic;
     this.dependencyTopic = dependencyTopic;
diff --git a/storage/src/main/java/zipkin2/storage/kafka/streams/TraceStorageTopology.java b/storage/src/main/java/zipkin2/storage/kafka/streams/TraceStorageTopology.java
index 300ae30b..a2dbbc16 100644
--- a/storage/src/main/java/zipkin2/storage/kafka/streams/TraceStorageTopology.java
+++ b/storage/src/main/java/zipkin2/storage/kafka/streams/TraceStorageTopology.java
@@ -80,7 +80,8 @@ public TraceStorageTopology(
       Duration traceTtlCheckInterval,
       long minTracesStored,
       boolean traceByIdQueryEnabled,
-      boolean traceSearchEnabled) {
+      boolean traceSearchEnabled
+  ) {
     this.spansTopic = spansTopic;
     this.autoCompleteKeys = autoCompleteKeys;
     this.traceTtl = traceTtl;