Cloudera, author of one of the most popular Hadoop distributions, has created a great tool for Hadoop security monitoring and auditing, called Cloudera Navigator. I find its initial configuration process a little bit tricky, so I wanted to document it in this post. Cloudera’s original document on how to do this is located here: http://www.cloudera.com/content/cloudera/en/documentation/core/latest/topics/cn_sg_external_auth.html I currently use the latest version of Cloudera Hadoop distribution with Cloudera Manager 5.3.1 (trial enterprise license) and Navigator 2....

Making another attempt to reactivate my OLED business card project. Due to lack of time and other priorities, I had to stop it for several months. I think that I’ve find an optimal hardware design and power source. Given limitations of ATtiny85, I started writing firmware in assembly, now I am starting it again in C. The board on picture was assembled to allow me work at kitchen table while watching my kids :)...

Hadoop has one security parameter, which importance I think is not stressed well enough in currently published documentation. While there are instructions on how to configure it, I did not see anyone talking about the consequences of leaving this parameter with its default value, and as far as I know, almost nobody ever changes it due to complexity. This parameter is **hadoop.security.auth_to_local - “**Maps kerberos principals to local user names”...

I often hear about the hard-coded ‘hdfs’ superuser in Hadoop clusters, and various challenges around managing it in scenarios when there is more than one team in the same organization using Hadoop in their projects. I think it’s very important to mention that there is no hardcoded ‘hdfs’ superuser in Hadoop. Name Node just gives admin rights to the system user name which started its process. So if you are starting Name Node as root (please don’t do this), your superuser name will be ‘root’....

I’ve spent the entire day solving this issue :) While all ATtiny85 were responsive and happy, both ATmega328 refused to work with avrdude throwing the error below while working perfectly with Arduino. The problem was that Arduino uses a 16Mhz external crystal as chip’s clock, and chip is pre-programmed to use it. Just add a 16 Mhz crystal with two 22 pF capacitors as at picture below: And microcontroller will respond to avrdude:...