For this Training VM, there is a hidden folder named .sys in the directory you are in above which contains a recreate_sandbox.sh script that can be used to recreate the Docker instance needed and get everything operational again. You can run it as shown below. root@ubuntu:~# cd .sys root@ubuntu:~/.sys# pwd /root/.sys root@ubuntu:~/.sys# ./recreate_sandbox.sh creating sandbox.... docker stop/waiting docker start/running, process 5857 inet addr:172.17.0.1 Bcast:0.0.0.0 Mask:255.255.0.0 sandbox started at 172.17.0.2 root@ubuntu:~/.sys# date Tue Sep 20 22:15:10 EDT 2016 root@ubuntu:~/.sys# date Tue Sep 20 22:19:51 EDT 2016 root@ubuntu:~/.sys# ssh sandbox The authenticity of host 'sandbox (172.17.0.2)' can't be established. RSA key fingerprint is 2e:0c:53:b1:d4:06:7d:ab:bd:79:f9:17:08:f2:8a:4b. Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added 'sandbox,172.17.0.2' (RSA) to the list of known hosts. Last login: Sun Dec 20 14:06:45 2015 from ip-172-17-0-1.ec2.internal [root@sandbox ~]# hdfs dfs -ls / Found 7 items drwxrwxrwx - yarn hadoop 0 2015-10-15 09:45 /app-logs drwxr-xr-x - hdfs hdfs 0 2015-10-15 09:45 /apps drwxr-xr-x - hdfs hdfs 0 2015-10-15 09:44 /hdp drwxr-xr-x - mapred hdfs 0 2015-10-15 09:44 /mapred drwxrwxrwx - mapred hadoop 0 2015-10-15 09:44 /mr-history drwxrwxrwx - hdfs hdfs 0 2015-10-15 09:46 /tmp drwxr-xr-x - hdfs hdfs 0 2015-10-20 14:31 /user [root@sandbox ~]# NOTE: If it fails again in the future, instead of recreating everything, try the restart_sandbox.sh script instead. ... View more

Just to make sure we are in-step on nomenclature. "Sources" and "Sinks" are http://flume.apache.org terminology as http://kafka.apache.org is all about Publishers and Subscribers that interact through Topics (aka message queues) that are persisted in a Kafka Cluster. If that makes sense and you just want to understand the interactions between Kafka publishers & subscribers then check out http://kafka.apache.org/intro for some introductory material. On the Flume front, it seems in 1.6.0 Kafka Source & Sink options became available as seen in the current (1.7.0) user guide at https://flume.apache.org/FlumeUserGuide.html. As a point of reference HDP 2.5 includes Flume 1.5.2 as detailed at http://docs.hortonworks.com/HDPDocuments/HDP2/HDP-2.5.0/bk_release-notes/content/ch_relnotes_v250.html, so that is not yet available via HDP. ... View more

The ALL are; especially when talking about so many files that were under-replicated. Ultimately, the NN is the one who determines if a file is under-replicated. It is then the NN's job to notify one of the DNs that has a good copy of one of the blocks' replicas to copy it to another DN. NN isn't going to do any of the actual movement of bits -- it will just coordinate the whole effort. Hope this helps! ... View more

I just peeked in the Training support system (the one triggered by emailing certification@hortonworks.com) and it looks like we're been able to discuss these items with you. I'll send you a quick update from the ones I'm aware of and see if we can fully run to ground your concerns. If I miss anything then please reply to the particular automated email and we'll work to make sure you have answers to your questinos. Thanks! ... View more

You are correct that we do not post any sample questions for the HCA certification, but we will evaluate if that is a logical step for this entry-level certification. You correctly found the objectives at http://hortonworks.com/wp-content/uploads/2016/08/ExamObjectives-HCAssociate.pdf and while these are "vast" as you described, please note that the HCA "provides for individuals an entry point and validates the fundamental skills required to progress to the higher levels of the Hortonworks certification program". If you are comfortable with the materials discussed in the Hadoop Essentials course, http://hortonworks.com/training/class/hadoop-essentials/, then you are an ideal candidate for this examination. Good luck! ... View more

@Artem Ervits is right; this would defeat the purpose of the test. ... View more