hadoop/hadoop-mapreduce/hadoop-yarn

YARN (YET ANOTHER RESOURCE NEGOTIATOR or YARN Application Resource Negotiator)
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Requirements
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Java: JDK 1.6
Maven: Maven 3

Setup
-----
Install protobuf 2.4.0a or higher (Download from http://code.google.com/p/protobuf/downloads/list)
- install the protoc executable (configure, make, make install)
- install the maven artifact (cd java; mvn install)
Installing protoc requires gcc 4.1.x or higher.
If the make step fails with (Valid until a fix is released for protobuf 2.4.0a)
./google/protobuf/descriptor.h:1152: error:
`google::protobuf::internal::Mutex*google::protobuf::DescriptorPool::mutex_'
is private
Replace descriptor.cc with http://protobuf.googlecode.com/svn-history/r380/trunk/src/google/protobuf/descriptor.cc


Quick Maven Tips
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clean workspace: mvn clean
compile and test: mvn install
skip tests: mvn install -DskipTests
skip test execution but compile: mvn install -Dmaven.test.skip.exec=true
skip native build: mvn -fn install -P-cbuild
clean and test: mvn clean install
run selected test after compile: mvn test -Dtest=TestClassName (combined: mvn clean install -Dtest=TestClassName)
create runnable binaries after install: mvn assembly:assembly (combined: mvn clean install assembly:assembly)


Eclipse Projects
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http://maven.apache.org/guides/mini/guide-ide-eclipse.html

1. Generate .project and .classpath files in all maven modules
mvn eclipse:eclipse
CAUTION: If the project structure has changed from your previous workspace, clean up all .project and .classpath files recursively. Then run:
mvn eclipse:eclipse

2. Import the projects in eclipse.

3. Set the environment variable M2_REPO to point to your .m2/repository location.

NetBeans Projects
-----------------

NetBeans has builtin support of maven projects. Just "Open Project..."
and everything is setup automatically. Verified with NetBeans 6.9.1.


Custom Hadoop Dependencies
--------------------------

By default Hadoop dependencies are specified in the top-level pom.xml
properties section. One can override them via -Dhadoop-common.version=...
on the command line. ~/.m2/settings.xml can also be used to specify
these properties in different profiles, which is useful for IDEs.

Modules
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YARN consists of multiple modules. The modules are listed below as per the directory structure:

hadoop-yarn-api - Yarn's cross platform external interface

hadoop-yarn-common - Utilities which can be used by yarn clients and server

hadoop-yarn-server - Implementation of the hadoop-yarn-api
hadoop-yarn-server-common - APIs shared between resourcemanager and nodemanager
hadoop-yarn-server-nodemanager (TaskTracker replacement)
hadoop-yarn-server-resourcemanager (JobTracker replacement)