Typical Flume Configuration Parameters

Overview

This section describes how to configure the sources, channels, and sinks of Flume, and modify the configuration items of each module.

For MRS 3.x or later, log in to FusionInsight Manager and choose Cluster > Services > Flume. On the displayed page, click the Configuration Tool tab, select and drag the source, channel, and sink to be used to the GUI on the right, and double-click them to configure corresponding parameters. Parameters such as channels and type are configured only in the client configuration file properties.properties, the path of which is Flume client installation directory/fusioninsight-flume-Flume version/conf/properties.properties.

You must input encrypted information for some configurations. For details on how to encrypt information, see Using the Encryption Tool of the Flume Client.

Common Source Configurations

• Avro Source

  Avro Source monitors the Avro port, receives data from the external Avro client, and puts the data into the configured channel. Table 1 lists common configurations.

  Figure 1 Avro Source
  

  Table 1 Common configurations of an Avro source

  Parameter	Default Value	Description
  channels	-	Specifies the channel connected to the source. Multiple channels can be configured. Use spaces to separate them. In a single proxy process, sources and sinks are connected through channels. A source instance corresponds to multiple channels, but a sink instance corresponds only to one channel. The format is as follows: <Agent >.sources.<Source>.channels = <channel1> <channel2> <channel3>... <Agent >.sinks.<Sink>.channels = <channel1> This parameter can be configured only in the properties.properties file.
  type	avro	Specifies the type, which is set to avro. The type of each source is a fixed value. This parameter can be configured only in the properties.properties file.
  bind	-	Specifies the host name or IP address associated with the source.
  port	-	Specifies the bound port number.
  ssl	false	Specifies whether to use SSL encryption. true false
  truststore-type	JKS	Specifies the Java trust store type. Set this parameter to JKS or other truststore types supported by Java.
  truststore	-	Specifies the Java trust store file.
  truststore-password	-	Specifies the Java trust store password.
  keystore-type	JKS	Specifies the key storage type. Set this parameter to JKS or other truststore types supported by Java.
  keystore	-	Specifies the key storage file.
  keystore-password	-	Specifies the key storage password.

• SpoolDir Source

  A SpoolDir source monitors and transmits new files that have been added to directories in quasi-real-time mode. Common configurations are as follows:

  Figure 2 SpoolDir Source
  

  Table 2 Common configurations of a SpoolDir source

  Parameter	Default Value	Description
  channels	-	Specifies the channel connected to the source. Multiple channels can be configured. This parameter can be configured only in the properties.properties file.
  type	spooldir	Type, which is set to spooldir. This parameter can be configured only in the properties.properties file.
  monTime	0 (Disabled)	Specifies the thread monitoring threshold. When the update time exceeds the threshold, the source is restarted. Unit: second
  spoolDir	-	Specifies the monitoring directory.
  fileSuffix	.COMPLETED	Specifies the suffix added after file transmission is complete.
  deletePolicy	never	Specifies the source file deletion policy after file transmission is complete. The value can be either never or immediate.
  ignorePattern	^$	Specifies the regular expression of a file to be ignored.
  trackerDir	.flumespool	Specifies the metadata storage path during data transmission.
  batchSize	1000	Specifies the source transmission granularity.
  decodeErrorPolicy	FAIL	Specifies the code error policy. This parameter can be configured only in the properties.properties file. The value can be FAIL, REPLACE, or IGNORE. FAIL: Generate an exception and fail the parsing. REPLACE: Replace the characters that cannot be identified with other characters, such as U+FFFD. IGNORE: Discard character strings that cannot be parsed. NOTE: If a code error occurs in the file, set decodeErrorPolicy to REPLACE or IGNORE. Flume will skip the code error and continue to collect subsequent logs.
  deserializer	LINE	Specifies the file parser. The value can be either LINE or BufferedLine. When the value is set to LINE, characters read from the file are transcoded one by one. When the value is set to BufferedLine, one line or multiple lines of characters read from the file are transcoded in batches, which delivers better performance.
  deserializer.maxLineLength	2048	Specifies the maximum length for resolution by line, ranging from 0 to 2,147,483,647.
  deserializer.maxBatchLine	1	Specifies the maximum number of lines for resolution by line. If multiple lines are set, maxLineLength must be set to a corresponding multiplier. For example, if maxBatchLine is set to 2, maxLineLength is set to 4096 (2048 x 2).
  selector.type	replicating	Specifies the selector type. The value can be either replicating or multiplexing. replicating indicates that the same content is sent to each channel. multiplexing indicates that the content is sent only to certain channels according to the distribution rule.
  interceptors	-	Specifies the interceptor. For details, see the Flume official document at https://flume.apache.org/FlumeUserGuide.html#flume-interceptors. This parameter can be configured only in the properties.properties file.

  

  The Spooling source ignores the last line feed character of each event when data is read by line. Therefore, Flume does not calculate the data volume counters used by the last line feed character.

• Kafka Source

  A Kafka source consumes data from Kafka topics. Multiple sources can consume data of the same topic, and the sources consume different partitions of the topic. Common configurations are as follows:

  Figure 3 Kafka Source
  

  Table 3 Common configurations of a Kafka source

  Parameter	Default Value	Description
  channels	-	Specifies the channel connected to the source. Multiple channels can be configured. This parameter can be configured only in the properties.properties file.
  type	org.apache.flume.source.kafka.KafkaSource	Specifies the type, which is set to org.apache.flume.source.kafka.KafkaSource. This parameter can be configured only in the properties.properties file.
  monTime	0 (Disabled)	Specifies the thread monitoring threshold. When the update time exceeds the threshold, the source is restarted. Unit: second
  nodatatime	0 (Disabled)	Specifies the alarm threshold. An alarm is triggered when the duration that Kafka does not release data to subscribers exceeds the threshold. Unit: second
  batchSize	1000	Specifies the number of events written into a channel at a time.
  batchDurationMillis	1000	Specifies the maximum duration of topic data consumption at a time, expressed in milliseconds.
  keepTopicInHeader	false	Specifies whether to save topics in the event header. If topics are saved, topics configured in Kafka sinks become invalid. true false This parameter can be configured only in the properties.properties file.
  keepPartitionInHeader	false	Specifies whether to save partition IDs in the event header. If partition IDs are saved, Kafka sinks write data to the corresponding partitions. true false This parameter can be set only in the properties.properties file.
  kafka.bootstrap.servers	-	Specifies the list of Broker addresses, which are separated by commas.
  kafka.consumer.group.id	-	Specifies the Kafka consumer group ID.
  kafka.topics	-	Specifies the list of subscribed Kafka topics, which are separated by commas (,).
  kafka.topics.regex	-	Specifies the subscribed topics that comply with regular expressions. kafka.topics.regex has a higher priority than kafka.topics and will overwrite kafka.topics.
  kafka.security.protocol	SASL_PLAINTEXT	Specifies the security protocol of Kafka. The value must be set to PLAINTEXT for clusters in which Kerberos authentication is disabled.
  kafka.kerberos.domain.name	-	Specifies the value of default_realm of Kerberos in the Kafka cluster, which should be configured only for security clusters. This parameter can be set only in the properties.properties file.
  Other Kafka Consumer Properties	-	Specifies other Kafka configurations. This parameter can be set to any consumption configuration supported by Kafka, and the .kafka prefix must be added to the configuration. This parameter can be set only in the properties.properties file.

• Taildir Source

  A Taildir source monitors file changes in a directory and automatically reads the file content. In addition, it can transmit data in real time. Table 4 lists common configurations.

  Figure 4 Taildir Source
  

  Table 4 Common configurations of a Taildir source

  Parameter	Default Value	Description
  channels	-	Specifies the channel connected to the source. Multiple channels can be configured. This parameter can be set only in the properties.properties file.
  type	taildir	Specifies the type, which is set to taildir. This parameter can be set only in the properties.properties file.
  filegroups	-	Specifies the group name of a collection file directory. Group names are separated by spaces.
  filegroups.<filegroupName>.parentDir	-	Specifies the parent directory. The value must be an absolute path. This parameter can be set only in the properties.properties file.
  filegroups.<filegroupName>.filePattern	-	Specifies the relative file path of the file group's parent directory. Directories can be included and regular expressions are supported. It must be used together with parentDir. This parameter can be set only in the properties.properties file.
  positionFile	-	Specifies the metadata storage path during data transmission.
  headers.<filegroupName>.<headerKey>	-	Specifies the key-value of an event when data of a group is being collected. This parameter can be set only in the properties.properties file.
  byteOffsetHeader	false	Specifies whether each event header should contain the location information about the event in the source file. The location information is saved in the byteoffset variable.
  skipToEnd	false	Specifies whether Flume can locate the latest location of a file and read the latest data after restart.
  idleTimeout	120000	Specifies the idle duration during file reading, expressed in milliseconds. If the file data is not changed in this idle period, the source closes the file. If data is written into this file after it is closed, the source opens the file and reads data.
  writePosInterval	3000	Specifies the interval for writing metadata to a file, expressed in milliseconds.
  batchSize	1000	Specifies the number of events written to the channel in batches.
  monTime	0 (Disabled)	Specifies the thread monitoring threshold. When the update time exceeds the threshold, the source is restarted. Unit: second

• Http Source

  An HTTP source receives data from an external HTTP client and sends the data to the configured channels. Table 5 lists common configurations.

  Figure 5 Http Source
  

  Table 5 Common configurations of an HTTP source

  Parameter	Default Value	Description
  channels	-	Specifies the channel connected to the source. Multiple channels can be configured. This parameter can be set only in the properties.properties file.
  type	http	Specifies the type, which is set to http. This parameter can be set only in the properties.properties file.
  bind	-	Specifies the name or IP address of the bound host.
  port	-	Specifies the bound port.
  handler	org.apache.flume.source.http.JSONHandler	Specifies the message parsing method of an HTTP request. The following methods are supported: org.apache.flume.source.http.JSONHandler: JSON org.apache.flume.sink.solr.morphline.BlobHandler: BLOB
  handler.*	-	Specifies handler parameters.
  enableSSL	false	Specifies whether SSL is enabled in HTTP.
  keystore	-	Specifies the keystore path set after SSL is enabled in HTTP.
  keystorePassword	-	Specifies the keystore password set after SSL is enabled in HTTP.

Common Channel Configurations

• Memory Channel

  A memory channel uses memory as the cache. Events are stored in memory queues. Table 6 lists common configurations.

  Figure 6 Memory Channel
  

  Table 6 Common configurations of a memory channel

  Parameter	Default Value	Description
  type	-	Specifies the type, which is set to memory. This parameter can be set only in the properties.properties file.
  capacity	10000	Specifies the maximum number of events cached in a channel.
  transactionCapacity	1000	Specifies the maximum number of events accessed each time.
  channelfullcount	10	Specifies the channel full count. When the count reaches the threshold, an alarm is reported.

• File Channel

  A file channel uses local disks as the cache. Events are stored in the folder specified by dataDirs. Table 7 lists common configurations.

  Figure 7 File Channel
  

  Table 7 Common configurations of a file channel

  Parameter	Default Value	Description
  type	-	Specifies the type, which is set to file. This parameter can be set only in the properties.properties file.
  checkpointDir	${BIGDATA_DATA_HOME}/flume/checkpoint	Specifies the checkpoint storage directory.
  dataDirs	${BIGDATA_DATA_HOME}/flume/data	Specifies the data cache directory. Multiple directories can be configured to improve performance. The directories are separated by commas (,).
  maxFileSize	2146435071	Specifies the maximum size of a single cache file, expressed in bytes.
  minimumRequiredSpace	524288000	Specifies the minimum idle space in the cache, expressed in bytes.
  capacity	1000000	Specifies the maximum number of events cached in a channel.
  transactionCapacity	10000	Specifies the maximum number of events accessed each time.
  channelfullcount	10	Specifies the channel full count. When the count reaches the threshold, an alarm is reported.

• Kafka Channel
  A Kafka channel uses a Kafka cluster as the cache. Kafka provides high availability and multiple copies to prevent data from being immediately consumed by sinks when Flume or Kafka Broker crashes. Table 10 Common configurations of a Kafka channel lists common configurations.

  Figure 8 Kafka Channel
  

  Table 8 Common configurations of a Kafka channel

  Parameter	Default Value	Description
  type	-	Specifies the type, which is set to org.apache.flume.channel.kafka.KafkaChannel. This parameter can be set only in the properties.properties file.
  kafka.bootstrap.servers	-	Specifies the list of Brokers in the Kafka cluster.
  kafka.topic	flume-channel	Specifies the Kafka topic used by the channel to cache data.
  kafka.consumer.group.id	flume	Specifies the Kafka consumer group ID.
  parseAsFlumeEvent	true	Specifies whether data is parsed into Flume events.
  migrateZookeeperOffsets	true	Specifies whether to search for offsets in ZooKeeper and submit them to Kafka when there is no offset in Kafka.
  kafka.consumer.auto.offset.reset	latest	Consumes data from the specified location when there is no offset.
  kafka.producer.security.protocol	SASL_PLAINTEXT	Specifies the Kafka producer security protocol.
  kafka.consumer.security.protocol	SASL_PLAINTEXT	Specifies the Kafka consumer security protocol.

Common Sink Configurations

• HDFS Sink

  An HDFS sink writes data into HDFS. Table 9 lists common configurations.

  Figure 9 HDFS Sink
  

  Table 9 Common configurations of an HDFS sink

  Parameter	Default Value	Description
  channel	-	Specifies the channel connected to the sink. This parameter can be set only in the properties.properties file.
  type	hdfs	Specifies the type, which is set to hdfs. This parameter can be set only in the properties.properties file.
  monTime	0 (Disabled)	Specifies the thread monitoring threshold. When the update time exceeds the threshold, the sink is restarted. Unit: second
  hdfs.path	-	Specifies the HDFS path.
  hdfs.inUseSuffix	.tmp	Specifies the suffix of the HDFS file to which data is being written.
  hdfs.rollInterval	30	Specifies file rolling by time, in seconds. Set hdfs.fileCloseByEndEvent to false if you set this parameter.
  hdfs.rollSize	1024	Specifies file rolling by size, in bytes. Set hdfs.fileCloseByEndEvent to false if you set this parameter.
  hdfs.rollCount	10	Specifies file rolling by the number of events, set hdfs.fileCloseByEndEvent to false if you set this parameter.
  hdfs.idleTimeout	0	Specifies the timeout interval for closing idle files automatically, expressed in seconds.
  hdfs.batchSize	1000	Specifies the number of events written into HDFS at a time.
  hdfs.kerberosPrincipal	-	Specifies the Kerberos username for HDFS authentication. This parameter is not required for a cluster in which Kerberos authentication is disabled.
  hdfs.kerberosKeytab	-	Specifies the Kerberos keytab of HDFS authentication. This parameter is not required for a cluster in which Kerberos authentication is disabled.
  hdfs.fileCloseByEndEvent	true	Specifies whether to close the file when the last event is received.
  hdfs.batchCallTimeout	-	Specifies the timeout control duration each time events are written into HDFS, expressed in milliseconds. If this parameter is not specified, the timeout duration is controlled when each event is written into HDFS. When the value of hdfs.batchSize is greater than 0, configure this parameter to improve the performance of writing data into HDFS. NOTE: The value of hdfs.batchCallTimeout depends on hdfs.batchSize. A greater hdfs.batchSize requires a larger hdfs.batchCallTimeout. If the value of hdfs.batchCallTimeout is too small, writing events to HDFS may fail.
  serializer.appendNewline	true	Specifies whether to add a line feed character (\n) after an event is written to HDFS. If a line feed character is added, the data volume counters used by the line feed character will not be calculated by HDFS sinks.

• Avro Sink

  Avro Sink converts events into Avro events and sends them to the monitoring ports of the hosts. Table 10 lists common configurations.

  Figure 10 Avro Sink
  

  Table 10 Common configurations of an Avro sink

  Parameter	Default Value	Description
  channel	-	Specifies the channel connected to the sink. This parameter can be set only in the properties.properties file.
  type	-	Specifies the type, which is set to avro. This parameter can be set only in the properties.properties file.
  hostname	-	Specifies the name or IP address of the bound host.
  port	-	Specifies the monitoring port.
  batch-size	1000	Specifies the number of events sent in a batch.
  ssl	false	Specifies whether to use SSL encryption.
  truststore-type	JKS	Specifies the Java trust store type.
  truststore	-	Specifies the Java trust store file.
  truststore-password	-	Specifies the Java trust store password.
  keystore-type	JKS	Specifies the key storage type.
  keystore	-	Specifies the key storage file.
  keystore-password	-	Specifies the key storage password.

• HBase Sink

  An HBase sink writes data into HBase. Table 11 lists common configurations.

  Figure 11 HBase Sink
  

  Table 11 Common configurations of an HBase sink

  Parameter	Default Value	Description
  channel	-	Specifies the channel connected to the sink. This parameter can be set only in the properties.properties file.
  type	-	Specifies the type, which is set to hbase. This parameter can be set only in the properties.properties file.
  table	-	Specifies the HBase table name.
  monTime	0 (Disabled)	Specifies the thread monitoring threshold. When the update time exceeds the threshold, the sink is restarted. Unit: second
  columnFamily	-	Specifies the HBase column family.
  batchSize	1000	Specifies the number of events written into HBase at a time.
  kerberosPrincipal	-	Specifies the Kerberos username for HBase authentication. This parameter is not required for a cluster in which Kerberos authentication is disabled.
  kerberosKeytab	-	Specifies the Kerberos keytab of HBase authentication. This parameter is not required for a cluster in which Kerberos authentication is disabled.

• Kafka Sink

  A Kafka sink writes data into Kafka. Table 12 lists common configurations.

  Figure 12 Kafka Sink
  

  Table 12 Common configurations of a Kafka sink

  Parameter	Default Value	Description
  channel	-	Specifies the channel connected to the sink. This parameter can be set only in the properties.properties file.
  type	-	Specifies the type, which is set to org.apache.flume.sink.kafka.KafkaSink. This parameter can be set only in the properties.properties file.
  kafka.bootstrap.servers	-	Specifies the list of Kafka Brokers, which are separated by commas.
  monTime	0 (Disabled)	Specifies the thread monitoring threshold. When the update time exceeds the threshold, the sink is restarted. Unit: second
  kafka.topic	default-flume-topic	Specifies the topic where data is written.
  flumeBatchSize	1000	Specifies the number of events written into Kafka at a time.
  kafka.security.protocol	SASL_PLAINTEXT	Specifies the security protocol of Kafka. The value must be set to PLAINTEXT for clusters in which Kerberos authentication is disabled.
  kafka.kerberos.domain.name	-	Specifies the Kafka domain name. This parameter is mandatory for a security cluster. This parameter can be set only in the properties.properties file.
  Other Kafka Producer Properties	-	Specifies other Kafka configurations. This parameter can be set to any production configuration supported by Kafka, and the .kafka prefix must be added to the configuration. This parameter can be set only in the properties.properties file.