A Native C/C++ HDFS Client
The Hadoop Distributed File System (HDFS) is a distributed file system designed to run on commodity hardware. HDFS is highly fault-tolerant and is designed to be deployed on low-cost hardware. HDFS provides high throughput access to application data and is suitable for applications that have large data sets.
HDFS is implemented in JAVA language and additionally provides a JNI based C language library libhdfs. To use libhdfs, users must deploy the HDFS jars on every machine. This adds operational complexity for non-Java clients that just want to integrate with HDFS.
Libhdfs3, designed as an alternative implementation of libhdfs, is implemented based on native Hadoop RPC protocol and HDFS data transfer protocol. It gets rid of the drawbacks of JNI, and it has a lightweight, small memory footprint code base. In addition, it is easy to use and deploy.
Libhdfs3 is developed by Pivotal and used in HAWQ, which is a massive parallel database engine in Pivotal Hadoop Distribution.
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To build libhdfs3, the following libraries are needed.
cmake (2.8+) http://www.cmake.org/
boost (tested on 1.53+) http://www.boost.org/
google protobuf http://code.google.com/p/protobuf/
libxml2 http://www.xmlsoft.org/
kerberos http://web.mit.edu/kerberos/
libgsasl http://www.gnu.org/software/gsasl/
To run code coverage test, the following tools are needed.
gcov (included in gcc distribution)
lcov (tested on 1.9) http://ltp.sourceforge.net/coverage/lcov.php
Assume libhdfs3 home directory is LIBHDFS3_HOME.
cd LIBHDFS3_HOME
mkdir build
cd build
../bootstrap
Environment variable CC and CXX can be used to setup the compiler. Script "bootstrap" is basically a wrapper of cmake command, user can use cmake directly to tune the configuration.
Run command "../bootstrap --help" for more configuration.
Run command to build
make
To build concurrently, rum make with -j option.
make -j8
To do unit test, run command
make unittest
To do function test, first start HDFS, and create the function test configure file at LIBHDFS3_HOME/test/data/function-test.xml, an example can be found at LIBHDFS3_HOME/test/data/function-test.xml.example. And run command.
make functiontest
To show code coverage result, run command. Code coverage result can be found at BUILD_DIR/CodeCoverageReport/index.html
make ShowCoverage
To install libhdfs3, run command
make install