When VirtualHost does not work in Apache 2.2 — If you wanted to use VirtualHost, but it shows Testing 123... only, you should check your server configuration. You cam simply check your server if configuration works or not by httpd -S
503 Service Unavailable Error displayed in Apache Reverse Proxy environment — If you see 503 Service Unavailable Error in Apache Reverse Proxy Environment with the perfect settings, it might be something associated with server security - it can be solved by /usr/sbin/setsebool
Apache Spark —
Apache Spark is an open-source distributed general-purpose cluster-computing framework.
- Spark was initially started by Matei Zaharia at UC Berkeley's AMPLab in 2009, and open sourced in 2010 under a BSD license.
- In 2013, the project was donated to the Apache Software Foundation and switched its license to Apache 2.0. In February 2014, Spark became a Top-Level Apache Project.
- In November 2014, Spark founder M. Zaharia's company Databricks set a new world record in large scale sorting using Spark.
- Spark had in excess of 1000 contributors in 2015, making it one of the most active projects in the Apache Software Foundation and one of the most active open source big data projects.
- Given the popularity of the platform by 2014, paid programs like General Assembly and free fellowships like The Data Incubator have started offering customized training courses
Secure and Scalable LAMP Service Architecture in AWS — LAMP means Linux + Apache + MySQL + PHP that is commonly used to develop web service for Start-ups that does not require paying license fee, because all of technologies are from open source.