@Sami Ahmad Please save ambari-server and ambari-agent logs on the journal node machines for further reference. One h@cky approach could be - 1. Copy the link from browser's address bar where enable Namenode HA wizard is stuck. 2. Open new tab in the same browser. 3. Paste the copied link. 4. increase the step number manually, i.e. if step4 is the last value in the copied url then make it as step5 5. press enter and move on! Please don't forget to create a Hortonworks Support ticket if you have a support subscription, it will help us to identify a BUG and fix it to avoid further occurrences of this issue. Hope this helps! -Kuldeep ... View more

@Regina Christiany I would recommend you to start learning HDFS and YARN architecture first. Once you understand the architecture then you can download our HDP sandbox from hortonworks.com and play around with it. Please do some research about your domain and decide on what all Hadoop Ecosystems(Hive/Pig/Spark etc.) you need work on and start reading about them one by one. While learning Hadoop and ecosystems, if you have any doubt, please post it here on HCC. We would be happy to help you! 🙂 All the Best. Happy Hadooping!! 🙂 Below are recommended books which would help you to start learning about HDFS and Yarn http://www.amazon.in/Hadoop-Definitive-Guide-Tom-White/dp/9352130677/ref=sr_1_1?s=books&ie=UTF8&qid=1484732267&sr=1-1&keywords=hadoop+definitive+guide https://www.amazon.in/Hadoop-Operations-Guide-Developers-Administrators-ebook/dp/B009J3I62I?ie=UTF8&tag=googinhydr18418-21 Hope this helps. ... View more