Overview
Flume is a distributed, reliable, and available service for efficiently collecting, aggregating, and moving large amounts of log data. It has a simple and flexible architecture based on streaming data flows. It is robust and fault tolerant with tunable reliability mechanisms and many fail over and recovery mechanisms. It uses a simple extensible data model that allows for online analytic application. Learn more at flume.apache.org.
This charm provides a Flume agent designed to ingest messages published to
a Kafka topic and send them to the apache-flume-hdfs
agent for storage in
the shared filesystem (HDFS) of a connected Hadoop cluster. This leverages the
KafkaSource jar packaged with Flume. Learn more about the
Flume Kafka Source.
Deploying
This charm requires Juju 2.0 or greater. If Juju is not yet set up, please follow the getting-started instructions prior to deploying this charm.
This charm is intended to be deployed via the hadoop-kafka bundle:
juju deploy hadoop-kafka
This will deploy an Apache Bigtop Hadoop cluster with Apache Flume and Apache Kafka. More information about this deployment can be found in the bundle readme.
Network-Restricted Environments
Charms can be deployed in environments with limited network access. To deploy in this environment, configure a Juju model with appropriate proxy and/or mirror options. See Configuring Models for more information.
Configuring
The default Kafka topic where messages are published is unset. Set this to an existing Kafka topic as follows:
juju config flume-kafka kafka_topic='<topic_name>'
If you don't have a Kafka topic, you may create one (and configure this charm to use it) with:
juju run-action kafka/0 create-topic topic=<topic_name> \
partitions=1 replication=1
juju show-action-output <id> # <-- id from above command
juju config flume-kafka kafka_topic='<topic_name>'
Once the Flume agents start, messages will start flowing into
HDFS in year-month-day directories here: /user/flume/flume-kafka/%y-%m-%d
.
Testing
A Kafka topic is required for this test. Topic creation is covered in the
Configuration section above. Generate Kafka messages with the write-topic
action:
juju run-action kafka/0 write-topic topic=<topic_name> data="This is a test"
To verify these messages are being stored into HDFS, SSH to the flume-hdfs
unit, locate an event, and cat it:
juju ssh flume-hdfs/0
hdfs dfs -ls /user/flume/flume-kafka # <-- find a date
hdfs dfs -ls /user/flume/flume-kafka/yyyy-mm-dd # <-- find an event
hdfs dfs -cat /user/flume/flume-kafka/yyyy-mm-dd/FlumeData.[id]