until another time...
Tuesday, August 26, 2014
This post is all about gadget envy. I just picked up a pair of bluetooth headphones following a Lifehacker deals post a few days ago. Here's the link to the post. I am by no means an audiophile, however, I was against getting bluetooth headphones for a long while. Recently, it dawned on me that BT headset is the only way to go for me when for the nth time my headphones stopped working in one ear. This deal is great and you may still have time to pick these up. Originally they're $80 and after a $50 off coupon provided at the link, these headphones are a steal for $30. They use the old 2.1 A2DP protocol but so far I haven't had any glaring issues with performance. Off the bat, the fit is very comfortable, something I've had issues with before with over the ear headphones. These do not snug tightly and don't make me feel like my head is in a vice. They come with a nice hard case, included is a 3.5mm cable and use the headphones just like any other wired set or use BT, the set also includes a USB charging cable, which is very convenient to have. I give the manufacturer two thumbs up for making the charger standard and I can charge my phone using the same cable. The headphones fold easily, have accessible buttons for volume, skip, stop, play. What sealed the deal for me was the fact that they also have a built-in mic. I barely every need to take my phone out of the pocket anymore. These headphones do sound a bit low compared to my wired Monoprice set but for the commute, they're better than any in-ear sets I've owned. The over the ear design offers great muffling of the background noise so having lower sound does not impede performance. Again, I am not an audiophile, these are great for podcasts and such, perhaps for classical music, you may need something else. I am very impressed and for $30 they're an incredible find. I forgot to mention that they also look great, they have an "expensive" look to them and they don't feel cheap. I recommend GOgroove BlueVIBE DLX for some casual listening.
Monday, August 25, 2014
I was trying to execute some run-of-the-mill Mapreduce against HBase on a development cluster running HDP 2.1 and discovered some gotchas going from HDP 2.0 to HDP 2.1. For the unaware, HDP 2.0 stack is Hadoop 2.2.0 and HBase 0.96.0 and HDP 2.1 is Hadoop 2.4.0 and HBase 0.98.0. The stack I used was 18.104.22.168 and then desperately upgraded to the brand-new 22.214.171.124 stack with YARN bug fixes. Spoiler, that did not solve the actual problem. On a side-note, there's a lot of "coincidental" advice out-there and I was not able to fix my issues on following this link http://www.srccodes.com/p/article/46/noclassdeffounderror-org-apache-hadoop-service-compositeservice-shell-exitcodeexception-classnotfoundexception. This article did however put me on the right path, I went to the nodemanager where the failing task attempt executed and looked up the "real" error. The problem was class not found for one library that was moved from hadoop-common Maven artifact to hadoop-yarn-common. I will update the post with the right error later. Once that's done basic jobs started running. I did encounter another issue and that issue is described in this Jira. I followed the same method as described previously, I went to the nodemanager logs and found the failing method call and found it to be described in the Jira above. So I just compiled my code using 2.4.1 version of Hadoop and lo and behold it executed the job successfully. So in summary, going from Hadoop 2.2 to Hadoop 2.4 in your Mapreduce code, make sure you change artifactId to hadoop-yarn-common from hadoop-common and compile with version 2.4.1.