KIP-1209 upgrade notes, config importance

Author: anton-liauchuk

connect/runtime/src/main/java/org/apache/kafka/connect/runtime/distributed/DistributedConfig.java

@@ -193,7 +193,7 @@ public final class DistributedConfig extends WorkerConfig {
     private static final String INTERNAL_TOPICS_AUTOMATIC_CREATION_ENABLE_DOC = "Whether to automatically create internal topics used by Connect. "
             + "This includes the offset, config, and status topics, as well as connector-specific offset topics "
             + "configured via 'offsets.storage.topic' in the source connector configuration.";
-    public static final Boolean INTERNAL_TOPICS_AUTOMATIC_CREATION_ENABLE_DEFAULT = true;
+    public static final boolean INTERNAL_TOPICS_AUTOMATIC_CREATION_ENABLE_DEFAULT = true;
 
     /**
      * <code>scheduled.rebalance.max.delay.ms</code>
@@ -439,7 +439,7 @@ private static ConfigDef config(Crypto crypto) {
                     INTERNAL_TOPICS_AUTOMATIC_CREATION_ENABLE_CONFIG,
                     Type.BOOLEAN,
                     INTERNAL_TOPICS_AUTOMATIC_CREATION_ENABLE_DEFAULT,
-                    ConfigDef.Importance.HIGH,
+                    ConfigDef.Importance.MEDIUM,
                     INTERNAL_TOPICS_AUTOMATIC_CREATION_ENABLE_DOC)
             .define(OFFSET_STORAGE_TOPIC_CONFIG,
                     ConfigDef.Type.STRING,

docs/getting-started/upgrade.md

@@ -47,6 +47,7 @@ type: docs
   * When clients connect to the cluster, they now include cluster and node information to enable detection and handling of misrouted connections. For further details, please refer to [KIP-1242](https://cwiki.apache.org/confluence/x/W4LMFw).
   * The `kafka-cluster.sh` tool now provides an `api-versions` command to display the API versions supported by the brokers or controllers, and it accepts both `--bootstrap-server` and `--bootstrap-controller`. As a result, `kafka-broker-api-versions.sh` is deprecated and will be removed in the next major release; use `kafka-cluster.sh api-versions` instead. For further details, please refer to [KIP-1220](https://cwiki.apache.org/confluence/x/-QkbFw).
   * Brokers can now record a human-readable description of each streams group's processing topology via a pluggable backend, retrievable through `Admin#describeStreamsGroups` and `kafka-streams-groups.sh --describe --topology`. The feature is disabled unless the new broker configuration `group.streams.topology.description.plugin.class` is set to a `StreamsGroupTopologyDescriptionPlugin` implementation; on the client side, the new Kafka Streams configuration `topology.description.push.enabled` (default `true`) controls whether the client pushes topology descriptions when requested. This adds a new RPC, `StreamsGroupTopologyDescriptionUpdate`, bumps `StreamsGroupDescribe` and `StreamsGroupHeartbeat` to version 1, and introduces the error codes `GROUP_DELETION_FAILED` (134) and `STREAMS_TOPOLOGY_DESCRIPTION_UPDATE_FAILED` (135). `DeleteGroups` is bumped to version 3, adding a per-group `ErrorMessage` field so brokers can report why a group deletion failed (for example, when the plugin fails to delete its stored topology description, the group is not deleted and `GROUP_DELETION_FAILED` is returned; retrying the deletion is safe). For further details, please refer to [KIP-1331](https://cwiki.apache.org/confluence/display/KAFKA/KIP-1331%3A+Streams+Group+Topology+Description+Plugin) and the [Topology Description Plugin](/{version}/streams/developer-guide/topology-description-plugin/) documentation.
+  * Kafka Connect distributed workers now support the `internal.topics.automatic.creation.enable` configuration (default: `true`). When set to `false`, Connect will not automatically create internal topics (offset, config, status, and connector-specific offset topics) and will instead fail at startup if any of these topics are missing. A new `connect-internal-topics.sh` tool is also available for manually creating these topics. For further details, please refer to [KIP-1209](https://cwiki.apache.org/confluence/display/KAFKA/KIP-1209:+Add+configuration+to+control+internal+topic+creation+in+Kafka+Connect).
 
 ## Upgrading to 4.3.0