Tuesday, May 31, 2016

Java errors when using Apache Spark on Amazon EMR

When I attempt the sentiment analysis tutorial on Apache Spark Streaming Twitter using Apache Zeppelin Notebook on Amazon EMR. I often encountered some strange Java error like this:

java.net.ConnectException: Connection refused at java.net.PlainSocketImpl.socketConnect(Native Method)

After some searching on the AWS forum, you should enter the following JSON configuration when you launch the new Amazon EMR cluster. Note that the number of spark.executor.cores should match the number of nodes that you have.
    "Classification": "spark",
    "Properties": {
      "maximizeResourceAllocation": "true"
    "Classification": "spark-defaults",
    "Properties": {
      "spark.dynamicAllocation.enabled": "true",
      "spark.executor.memory": "5G",
      "spark.executor.cores": "1",

Saturday, February 27, 2016

Run Node.JS within Sublime Text editor

Step 1: Open "Sublime Text 2" editor
Step 2: Tools -> Build System -> New Build System
Step 3: New tab appears. Replace the content with the following lines.

"cmd": ["node", "$file", "$file_base_name"],
"working_dir": "${project_path:${folder}}",
"selector": "*.js"

Step 4: Save the file and rename it with "NodeJS.sublime-build".
Step 5: Select "Tools -> Build System -> NodeJS"
Step 6: Go to your source program and press "Ctrl-B" to run code.

Wednesday, February 3, 2016

Connect to WS2012 WSUS Internal Database

To connect to the Windows Internal Database (WID) WSUS, install SQL Management Studio and connect to the server using:


You may confirm the SQL instance name in red against the startup service description using services.msc.

As there is a constant error of "WSUS server is still processing a previous configuration change", this is what I need to execute on the database instance:

UPDATE tbSingletonData SET ResetStateMachineNeeded = 0

Monday, August 24, 2015

Making Sense of "User-Based Recommender in 5 minutes"

Have you wondered how Amazon recommend new items to you? This is an  example of Machine Learning implementation, which is a type of Artificial Intelligence. I have followed an introductory example of Apache Mahout and shared this on LinkedIn.