6. Configure Flume

Administrators edit three configuration files to configure a Flume agent:

flume.conf
flume-env.sh
log4j.properties

flume.conf

Configure each Flume agent by defining properties in a configuration file at /etc/flume/conf/flume.conf. The init scripts installed by the flume-agent package read the contents of this file to start a single Flume agent on any host. At a minimum, the Flume configuration file must specify the required sources, channels, and sinks for your Flume topology. For example, the following sample Flume configuration file defines a Netcat source, a Memory channel, and a Logger sink:

# example.conf: A single-node Flume configuration 

# Name the components on this agent
a1.sources = r1
a1.sinks = k1
a1.channels = c1 

# Describe/configure the source
a1.sources.r1.type = netcat
a1.sources.r1.bind = localhost
a1.sources.r1.port = 44444 

# Describe the sink a1.sinks.k1.type = logger 

# Use a channel which buffers events in memory
a1.channels.c1.type = memory
a1.channels.c1.capacity = 1000
a1.channels.c1.transactionCapacity = 100

# Bind the source and sink to the channel
a1.sources.r1.channels = c1
a1.sinks.k1.channel = c1

See the Apache Flume 1.4.0 User Guide for a complete list of all available Flume components. To see what configuration properties you can adjust, a template for this file is installed in the configuration directory at: /etc/flume/conf/flume.conf.properties.template. A second template file exists for setting environment variables automatically at start-up: /etc/flume/conf/flume-env.sh.template.

	Note
	Make sure to specify a target folder in HDFS if you use an HDFS sink.

flume-env.sh

Set environment options for a Flume agent in /etc/flume/conf/flume-env.sh:

To enable JMX monitoring, add the following properties to the JAVA_OPTS property:

JAVA_OPTS="-Dcom.sun.management.jmxremote
-Dcom.sun.management.jmxremote.port=4159
-Dcom.sun.management.jmxremote.authenticate=false
-Dcom.sun.management.jmxremote.ssl=false"

To enable Ganglia monitoring, add the following properties to the JAVA_OPTS property:
```
JAVA_OPTS="-Dflume.monitoring.type=ganglia
-Dflume.monitoring.hosts=<ganglia-server>:8660"
```
Where <ganglia-server> is the name of the Ganglia server host.

To customize the heap size, add the following properties to the JAVA_OPTS property:
```
JAVA_OPTS= "-Xms100m -Xmx4000m" 
```

log4j.properties

Set the log directory for log4j in /etc/flume/conf/log4j.properties:

flume.log.dir=/var/log/flume

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