Apache Flume Syslog

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 failover 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 receive remote syslog events and send them to the apache-flume-hdfs agent for storage into the shared filesystem (HDFS) of a connected Hadoop cluster. Think of this charm as a replacement for rsyslog, sending syslog events to HDFS instead of writing them to a local filesystem.

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 one of the apache bigtop bundles. For example:

juju deploy hadoop-processing

This will deploy an Apache Bigtop Hadoop cluster. More information about this deployment can be found in the bundle readme.

Now add Flume-HDFS and relate it to the cluster via the hadoop-plugin:

juju deploy apache-flume-hdfs flume-hdfs
juju add-relation flume-hdfs plugin

Now that the base environment has been deployed, add the apache-flume-syslog charm and relate it to the flume-hdfs agent:

juju deploy apache-flume-syslog flume-syslog
juju add-relation flume-syslog flume-hdfs

You are now ready to ingest remote syslog events! Note the deployment at this stage isn't very useful. You'll need to relate this charm to any other service that is configured to send data via the syslog interface.

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.

Testing

As an example use case, let's ingest our namenode syslog events into HDFS. Deploy the rsyslog-forwarder-ha subordinate charm, relate it to namenode, and then link the syslog interfaces:

juju deploy rsyslog-forwarder-ha
juju add-relation rsyslog-forwarder-ha namenode
juju add-relation rsyslog-forwarder-ha flume-syslog

Any syslog data generated on the namenode unit will now be ingested into HDFS via the flume-syslog and flume-hdfs charms. Flume may include multiple syslog events in each file written to HDFS. This is configurable with various options on the flume-hdfs charm. See descriptions of the roll_* options on the apache-flume-hdfs charm store page for more details.

Flume will write files to HDFS in the following location: /user/flume/<event_dir>/<yyyy-mm-dd>/FlumeData.<id>. The <event_dir> subdirectory is configurable and set to flume-syslog by default for this charm.

Verifying

To verify this charm is working as intended, trigger a syslog event on the monitored unit (namenode in our deployment scenario):

juju ssh namenode/0 'echo flume-test'

Now SSH to the flume-hdfs unit, locate an event, and cat it:

juju ssh flume-hdfs/0
hdfs dfs -ls /user/flume/<event_dir>               # <-- find a date
hdfs dfs -ls /user/flume/<event_dir>/<yyyy-mm-dd>  # <-- find an event
hdfs dfs -cat /user/flume/<event_dir>/<yyyy-mm-dd>/FlumeData.<id>

You should be able to find a timestamped message about SSH'ing into the namenode unit that corresponds to the trigger you issued above. Note that this workload isn't limited to ssh-related events. You'll get every syslog event from the namenode unit. Happy logging!

Contact Information

• bigdata@lists.ubuntu.com

Resources

• Apache Flume home page
• Apache Flume bug tracker
• Apache Flume mailing lists
• Juju mailing list
• Juju community