Starting a CDH5 yarn hadoop cluster with whirr on OpenStack

Just recently I was looking at some tools to start dynamic Hadoop cluster on our private OpenStack cloud.
The first one I evaluated was Apache Whirr. The project had once an active community but recently it seems to be almost dead. It is however still part of Cloudera CDH5 distribution so I decided to give it a shot.

Cloudera provides information on how to setup a CDH5 cluster at: http://www.cloudera.com/content/cloudera-content/cloudera-docs/CDH5/latest/CDH5-Installation-Guide/cdh5ig_whirr_define.html

Unfortunately it does not work with the CDH5 whirr as it does seem to be updated since CDH4 and is not aware of some of the  CDH5 settings.

Another problem is a whirr issue with official Ubuntu cloud images: (https://issues.apache.org/jira/browse/WHIRR-435). It appears that the new images use cloud-init to update the apt sources.list and there is a short period of timew when whirr can ssh to the machine (e.g. to start jdk installation) but still sees the outdated sources (which breaks jdk installation).

Finally the last official version of whirr (0.8.2) does not work with openjdk-6 (and some newer versions of orcacle jdk) - the issues was fixed in 0.9.1 - Luckily Cloudera's  CHD5 whirr has the fix.

I have managed to patch the installation functions to fix the issues mentioned above and finally be able to start my cluster.

The patches and sample configuration is avaliable at: https://github.com/piotrszul/whirr-chd5-openstack

Hadoop and OpenCV

Compiling OpenCV with Java

The info how to compile OpenCV is available at:
http://docs.opencv.org/doc/tutorials/introduction/desktop_java/java_dev_intro.html

Here are some additional notes for opencv-2.4.8

• Ubuntu 12.04: It compiles and works fine as is. However some extra packages are required including: build–essentials, libjpg-dev, python-dev, ant, libpng-dev and perhaps some other (see the cmake output). JAVA_HOME needs to be set to a JDK
• On Centos 6.2: cmake needs to be upgraded to 2.8.x (2.8.12.2). Some extra packages may be required e.g.: libjpg-devel, python-devel etc. There is bug in opencv-2.4.8 that results in SEGV while loading the library to JavaVM – to fix apply the patch before compilation: https://github.com/djetter99/opencv/commit/6bf599b1bca8a58c7a656ddc169f7be0fc3094c6
• On SUSE Linux Enterprise Server 11 SP2 (bragg cluster): apply the patch (see CentoOS). Load modules cmake, and gcc (does not compile with intel cc)

To apply the patch use (in opencv sources root dir):

# wget https://github.com/djetter99/opencv/commit/6bf599b1bca8a58c7a656ddc169f7be0fc3094c6.patch
# git apply 6bf599b1bca8a58c7a656ddc169f7be0fc3094c6.patch

Loading custom native libraries from in Hadoop

Native libraries need to be on the path defined by java java.library.path system property. It’s a bit confusing how to pass it to Hadoop workers as it depends on the mode (local vs distributed) and version.

For local run (that is one that does not involve spawning child jvms):

• set the additional path in JAVA_LIBRARY_PATH env variable

For distributed runs:

• copy the library to standard hadoop native path (e.g. /usr/lib/hadoop/lib/native)
• use the distributed cache as described: http://hadoop.apache.org/docs/r2.2.0/hadoop-project-dist/hadoop-common/NativeLibraries.html 
• in version 0.20 and 1.0 pass the additional paths (need to be available on worker nodes) in mapred.child.java.opts by defining java.library.path e.g.: -Dmapred.child.java.opts=”-Djava.library.path=/usr/local/lib”
• in version 2.0 pass the additional paths in the mapred.child.env property by defining JAVA_LIBRARY_PATH env variable (e.g.: -Dmapred.child.env=”JAVA_LIBRARY_PATH=/usr/local/lib”)