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Showing posts from May, 2016

Apache Oozie Overview, Quick Installation and Configuration

I just completed by Big Data Processing Using Hadoop class at John's Hopkins. The class started with a general overview of the Apache Hadoop platform with HDFS (Hadoop File System), Map Reduce framework. We dived into Pig, Hive and few other components. We completed 3 decent size projects and numerous lab assignments. Lab assignments were designed to get us introduced to these topics while assignments were designed to give us real life scenario problems and how this very complicated ecosystem of tools and ideas can be used to solve these problems. I very much enjoyed the topics and assignments in this class. We also had an opportunity to choose our own topic (outside of what was being taught in class) and present it in class. I thought this was a really nice opportunity to dive into one of those other Apache projects that compliment the Hadoop platform. Working on few of the assignments, it become clear to me that we really need a way to organize Hadoop Jobs into a workflow and

Cross Origin Resource Sharing (CORS) issues with Chrome on POST requests

Cross Origin Resource Sharing aka CORS is a mechanism that allows servers to access resources hosted on different domains (servers) through web browsers. Due to security restrictions of early web, browsers restricted cross origin HTTP requests initiated from within scripts (i.e JavaScript scripts). Using the XMLHttpRequest object you could only make HTTP requests to originating domains. You can now use CORS to access resources hosted on different domains within scripts. This is handled through setting of new HTTP header values. Server's making requests to access resources on different domains use "Origin" header to set where the request is coming from. Server's receiving such requests usually respond with other header values indicating whether Access Control is allowed. "Access-Control-Allow-Origin" header value is used for such purpose. Resource owners can use this header value to restrict access control to specific domains or allow access by all domain