Spark applications must be configured with a set of Kafka topics that are either shared between multiple applications or dedicated to specific applications. The assigned topics must be created before you submit an application to the Spark cluster. Before you can create the topics you must start Zookeeper and Kafka.
Starting Services
The prerequisites for starting services are the following:
Spark, ZooKeeper and Kafka are installed and up and running.
Scripts are prepared according to: 5.2 Preparing and Creating Scripts for KPI Management
| Info |
|---|
Example. Starting services. Startup Spark cluster:
|
You can now confirm the status of the Spark cluster. Open a browser and go to http://<master host>:8080.
Spark UI
Creating Kafka Topics
Create Kafka topics and partitions using the scripts included in the Kafka installation. The names of the topics must correspond to the Spark application configuration.
| Note |
|---|
In order for the Spark KPI Application to work, the required number of partitions for each topic must be equal to the setting of the property |
Use a replication factor that is greater than one (1) to make sure that data is replicated between Kafka brokers. This decreases the risk of losing data in case of issues with the brokers. This is how to create topics, assuming the current working directory is the Kafka software folder:
| Code Block | ||
|---|---|---|
| ||
$ ./bin/kafka-topics.sh --create --topic <input topic> --bootstrap-server \ localhost:9092 --partitions <number of partitions> --replication-factor <number of replicas> $ ./bin/kafka-topics.sh --create --topic <output topic> --bootstrap-server \ localhost:9092 --partitions <number of partitions> --replication-factor <number of replicas> $ ./bin/kafka-topics.sh --create --topic <alarm topic> --bootstrap-server \ localhost:9092 --partitions <number of partitions> --replication-factor <number of replicas> |
Example - Creating Kafka Topics:
| Code Block |
|---|
./bin/kafka-topics.sh --create --topic kpi-output --partitions 6 --replication-factor 1 ./bin/kafka-topics.sh --create --topic kpi-input --partitions 6 --replication-factor 1 ./bin/kafka-topics.sh --create --topic kpi-alarm --partitions 6 --replication-factor 1 |
Example - Creating Kafka topics, overriding retention settings
| Code Block |
|---|
./bin/kafka-topics.sh --create --topic kpi-output --partitions 6 --replication-factor 1 --config retention.ms=86400000 ./bin/kafka-topics.sh --create --topic kpi-input --partitions 6 --replication-factor 1 --config retention.ms=86400000 ./bin/kafka-topics.sh --create --topic kpi-alarm --partitions 6 --replication-factor 1 --config retention.ms=86400000 |