Apache-Kafka with to dCache, or how to push events outside of dCache.
Starting from version 4.1 we introduced a new approach to external messaging. With the introduction of Apache-Kafka (kafka.apache.org/documentation/) as a message transport, for now in Billing, we start switching to a more modern and efficient messaging system. The goal for the Billing service is easier inclusion with systems like Elasticsearch: Instead of adding messages to a textual log and having an external component parse that log, a Kafka-aware ingester can import them directly into the remote system.
What do you need to download to enable Kafka in dCache?
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ZooKeeper Framework
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Apache Kafka
Apache Kafka Installation.
1. Download
To install Kafka on your machine, click on the below link − https://www.apache.org/dyn/closer.cgi?path=/kafka/0.9.0.0/kafka_2.11-0.9.0.0.tgz
Extract the tar file
cd opt/
tar -zxf kafka_2.11.0.9.0.0 tar.gz
cd kafka_2.11.0.9.0.0
2. Enable kafka in dCache.
dcache.enable.kafka = true
Set the broker address, or list of broker addresses
dcache.kafka.bootstrap-servers = localhost:9092
Set kafka topic name
dcache.kafka.topic = billing
“billing” is default. The following serice level variables reference dcache.kafka.topic:
dcap.kafka.topic = ${dcache.kafka.topic} ftp.kafka.topic = ${dcache.kafka.topic} nfs.kafka.topic = ${dcache.kafka.topic} pool.kafka.topic = ${dcache.kafka.topic} webdav.kafka.topic = ${dcache.kafka.topic} xrootd.kafka.topic = ${dcache.kafka.topic}
3. Start Server
bin/kafka-server-start.sh config/server.properties
4. Start consumer
bin/kafka-console-consumer.sh --bootstrap-server localhost:9092 --topic billing --from-beginning