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<title>Apache Distributed UIMA Cluster Computing (DUCC) 2.2.2 Release Notes</title>
<h1>Apache UIMA-DUCC (Unstructured Information Management Architecture - Distributed UIMA Cluster Computing ) v.2.2.2 Release Notes</h1>
<a href="">1. What is UIMA-DUCC?</a><br/>
<a href="#major.changes">2. Major Changes in this Release</a><br/>
<a href="#migration">3. Migration from a Prior Release</a><br/>
<a href="#migration">4. Limitations</a><br/></p>
<h2><a name="">1. What is UIMA-DUCC?</a></h2>
DUCC stands for Distributed UIMA Cluster Computing. DUCC is a cluster management system providing tooling,
management, and scheduling facilities to automate the scale-out of applications written to the UIMA framework.
Core UIMA provides a generalized framework for applications that process unstructured information such as human
language, but does not provide a scale-out mechanism. UIMA-AS provides a scale-out mechanism to distribute UIMA
pipelines over a cluster of computing resources, but does not provide job or cluster management of the resources.
DUCC defines a formal job model that closely maps to a standard UIMA pipeline. Around this job model DUCC
provides cluster management services to automate the scale-out of UIMA pipelines over computing clusters.
<h2><a name="major.changes">2. Major Changes in this Release</a></h2>
Apache UIMA DUCC 2.2.2 is a maintenance release containing new features and bug fixes. What's new:<br>
<li>Upgraded UIMA (2.10.2), UIMA-AS (2.10.2), ActiveMQ (5.15.2), Spring Framework (4.3.9), Camel (2.19.3), XStream (1.4.10)</li>
<li>Requires java 8 for builds and runtime. User jobs and services must use java 8.</li>
<li>Fixed rogue process detector to prevent truncation of user names</li>
<li>Reduced size of publications between the PM and Agents</li>
<li>Improved Agent's detection of defunct processes</li>
<li>Improved logging of system events</li>
<li>ducc_watcher improvements</li>
<li>Job & managed reservation specs now saved in DB</li>
<li>DUCC Web Server (WS) queries DB too often</li>
<li>DUCC Web Server (WS) should use Resource Manager (RM) calculated value for machine's memory available</li>
For a complete list of issues fixed and up-to-date information on UIMA-DUCC issues, see our issue tracker:
<a href=""></a>
<h2><a name="migration">3. Migration from a Prior Release</a></h2>
When upgrading from an existing installation the ducc_update script may be used to replace the system files while leaving the site-specific configuration files in place. For more information see <strong>ducc_update</strong> in the Administrative Commands section of the DuccBook.
<h2><a name="limitations">4. Limitations</a></h2>
On some systems cgroups swap accounting is not enabled and duccmon will show N/A for swap. To
confirm, please check memory.stat file in <cgroups base dir>/ducc/ folder. If swap accounting is
enabled there should be "swap" property defined. If it's missing, you need to add a kernel parameter
swapaccount=1. Details of how to do this can be found <a href="">here</a>.
Due to a bug in uima sdk, the uima AnalysisEngineProcessException cannot be serialized as a Java object. If your
analysis engine throws an exception in process(), the ducc framework will stringify it and wrap it in
java RuntimeException. If you have a custom error handler plugged in into a job driver you will not be
able to test for AnalysisEngineProcessException in a stack trace with a code like this:
if ( error instanceof AnalysisEngineProcessException ) ...
To use OS-based login with the WebServer while running DUCC with IBM java, the minimum JDK version is
Java 8 SR4 FP5 (