Driven FAQversion 2.2.6
Yes, you can deploy Driven in both environments with a trial license, which you can obtain on the Driven Trial registration page.
Driven works with any version of Hadoop that is compatible with Cascading. See the Cascading compatibility matrixes for the full list of supported versions.
The matrix of supported JDKs is on the Cascading compatibility matrices page.
If your application executes successfully without the Driven Plugin, it executes successfully whether or not the Driven Plugin transmits all the telemetry data successfully. The push of the data to the Driven Server is decoupled from the execution of the MapReduce application.
The multilayered Driven web client renders much of the application performance data that the plugin sends. Provided that the Driven Server and the plugin are operational and connected, you should not typically need to go beyond the Driven graphical user interface to discover the information that you need.
An "archive mode" configuration is available for the plugin, which writes to disk all data that is sent by the plugin. The archive can be "replayed" to view the information in a log-like format. Archive mode allows you to view data transmitted from the plugin when the Driven Server is not functioning or cannot be accessed. The archive also provides additional details of application execution that are not displayed in the Driven web client.
To use archive mode:
Either pass the following JVM property to the job:
Or you can set the HADOOP_OPTS environment variable:
$ export HADOOP_OPTS="$HADOOP_OPTS -Dcascading.management.document.service.archive.dir=/path/to/archive"
The compressed archive files are saved to path names that consist of the application name and the ID. Do not use ~ expansion for the path.
By default the Driven webapp uses standard directories that should be accessible
to any webapp. If your particular installation does not allow this Driven can be
configured to store data somewhere other than the
default and to write logs somewhere other than the
OOM messages from the Driven Plugin are most likely a symptom of an error rather than an error itself.
Some possible underlying reasons for the OOM messages are:
The Cascading application is transmitting data to the Driven Plugin at a rate faster than the plugin can send the data to the Driven Server.
The Driven Server is unavailable.
The Cascading application is unable to connect to the Driven Server.
A cluster is inadequately provisioned for NameNode processes and the machine (Driven Plugin pings the NameNode for slice information). Try changing the
-Xmxsettings of your application and NameNode processes to the following:
If your application executes successfully without the Driven Plugin, it will execute successfully whether or not the Driven Plugin transmits all the telemetry data successfully. The push of the data to the Driven Server is decoupled from the execution of the MapReduce application.
I am seeing "java.io.IOException: java.util.prefs.BackingStoreException: Couldn’t get file lock" when installing a license
This is an issue with Java’s Preferences handling and some OS setups. The user
your webapp runs under (typically
tomcat7) needs write permissions
on its home directory.