Apache Flume Syslog
- By bigdata-charmers
- Big Data
juju deploy apache-flume-syslog
Discuss this charm
Share your thoughts on this charm with the community on discourse.
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!