From fae59d85a158d703d57160836c402729293fa86e Mon Sep 17 00:00:00 2001
From: Asiel Leal Celdeiro <15990580+lealceldeiro@users.noreply.github.com>
Date: Wed, 24 Jan 2024 01:14:40 +0200
Subject: [PATCH] Add notes: Kafka: The definitive guide

- Chapter 12: Administering Kafka
---
 KafkaTheDefinitiveGuide/Chapter12/README.md | 104 ++++++++++++++++++++
 KafkaTheDefinitiveGuide/README.md           |   2 +
 2 files changed, 106 insertions(+)
 create mode 100644 KafkaTheDefinitiveGuide/Chapter12/README.md

diff --git a/KafkaTheDefinitiveGuide/Chapter12/README.md b/KafkaTheDefinitiveGuide/Chapter12/README.md
new file mode 100644
index 0000000..2bdb88c
--- /dev/null
+++ b/KafkaTheDefinitiveGuide/Chapter12/README.md
@@ -0,0 +1,104 @@
+# CHAPTER 12: Administering Kafka
+
+While Apache Kafka implements authentication and authorization to control topic operations, default configurations do
+not restrict the use of these tools. This means that these CLI tools can be used without any authentication required,
+which will allow operations such as topic changes to be executed with no security check or audit.
+
+## Topic Operations
+
+The `kafka-topics.sh` tool provides easy access to most topic operations. It allows you to create, modify, delete, and
+list information about topics in the cluster. While some topic configurations are possible through this command, they
+have been deprecated, and it is recommended to use the more robust method of using the `kafka-config.sh` tool for
+configuration changes.
+
+## Consumer Groups
+
+The `kafka-consumer-groups.sh` tool helps manage and gain insight into the consumer groups that are consuming from
+topics in the cluster.
+
+## Dynamic Configuration Changes
+
+The `kafka-configs.sh` is the main tool for modifying all the configurations for topics, clients, brokers, and more that
+can be updated dynamically during runtime without having to shut down or redeploy a cluster.
+
+## Producing and Consuming
+
+To manually produce or consume some sample messages these tools are provided: `kafka-console-consumer.sh` and
+`kafka-console-producer.sh`.
+
+### Example
+
+Consuming the earliest message from the `__consumer_offsets` topic:
+
+```shell
+kafka-console-consumer.sh --bootstrap-server localhost:9092
+                          --topic __consumer_offsets --from-beginning --max-messages 1
+                          --formatter "kafka.coordinator.group.GroupMetadataManager\$OffsetsMessageFormatter"
+                          --consumer-property exclude.internal.topics=false
+```
+
+This will show something like this:
+
+```text
+[my-group-name,my-topic,0]::[OffsetMetadata[1,NO_METADATA]
+CommitTime 1623034799990 ExpirationTime 1623639599990]
+Processed a total of 1 messages
+```
+
+## Partition Management
+
+A default Kafka installation contains a few scripts for working with the management of partitions. One of these tools
+allows for the reelection of leader replicas; another is a low-level utility for assigning partitions to brokers.
+Together these tools can assist in situations where a more manual hands-on approach to balance message traffic within a
+cluster of Kafka brokers is needed.
+
+The `kafka-leader-election.sh` utility can be used to trigger manually a new leader election.
+
+### Example
+
+Start a preferred leader election for all topics in a cluster:
+
+```shell
+kafka-leader-election.sh --bootstrap-server localhost:9092 --election-type PREFERRED --all-topic-partitions
+```
+
+It is also possible to start elections on specific partitions or topics. This can be done by passing in a topic name
+with the `--topic` option and a partition with the `--partition` option directly. It is also possible to pass in a list
+of several partitions to be elected through a JSON file with the topic names.
+
+### Example
+
+Start a preferred replica election with a specified list of partitions in a file named `partitions.json`, with the
+following content:
+
+```json
+{
+  "partitions": [
+    {
+      "partition": 1,
+      "topic": "my-topic"
+    },
+    {
+      "partition": 2,
+      "topic": "foo"
+    }
+  ]
+}
+```
+
+```shell
+kafka-leader-election.sh --bootstrap-server localhost:9092 --election-type PREFERRED --path-to-json-file partitions.json
+```
+
+The `kafka-reassign-partitions.sh` can be used to change the replica assignments manually for a partition.
+
+The `kafka-dump-log.sh` tool can be used to decode the log segments for a partition.
+
+The `kafka-replica-verification.sh` tool can be used to validate that the replicas for a topic's partitions are the same
+across the cluster.
+
+## Unsafe Operations
+
+- Moving the Cluster Controller
+- Removing Topics to Be Deleted
+- Deleting Topics Manually
diff --git a/KafkaTheDefinitiveGuide/README.md b/KafkaTheDefinitiveGuide/README.md
index 1c4b48f..1f6e9ee 100644
--- a/KafkaTheDefinitiveGuide/README.md
+++ b/KafkaTheDefinitiveGuide/README.md
@@ -23,3 +23,5 @@ Main notes taken from the book [Kafka: The Definitive Guide: Real-Time Data and
 [CHAPTER 10: Cross-Cluster Data Mirroring](./Chapter10)
 
 [CHAPTER 11: Securing Kafka](./Chapter11)
+
+[CHAPTER 12: Administering Kafka](./Chapter12)