Hortonworks releases a set of icons today which can be download from here.
This is an unofficial set of icons for Hadoop projects, related components and resources that anyone can use to create architecture diagrams or other images. The icons are designed to be simple and flexible to assist comprehension in technical diagrams.
Recently I went through a literature which was given to me during a leadership training at my previous work. I wanted to live through the training again and decided to follow it again completely. The content was great and it was mainly conveying 3 main things to become a successful leader:
A leader is consider to be like the “paddle” for the boat. The “paddle” seems to look very small comparative to the “boat” however it is “paddle” who gives the direction to boat and help reaching to its destination . Everyone sees the “boat” however no one see the “paddle”. Now these days leaders are like “flag” on the boat who are there to show off and get the credit from the “paddle”.
I would say that as being new to mac, I found zsh shell is one of the best and I am digging more about it every day. I thought this article would be helpful for someone who is in need of a great terminal application. The zsh shell comes with lots of themes to beautify the static terminal. I use iTerm2 on my mac and using zsh with it, the combination made in heaven.
I use brew on my mac (as application installer) so using brew to install zsh shell on mac is the best option however it will only work if the zsh package is available through brew installer. If you don’t have brew on your mac you can install just by visiting the site below and follow the instructions:
To check if any application or package is available on through brew you can try:
$ brew search <package_name>
$ brew search zsh
zsh
zsh-completions
zsh-lovers
zsh-syntax-highlighting
zshdb
As we can see above the zsh package is available so we can get more info about it as below:
$ brew info <package_name>
$ brew info zsh
zsh: stable 5.0.2
http://www.zsh.org/
/usr/local/Cellar/zsh/5.0.2 (1053 files, 8.7M) *
Built from source
From: https://github.com/mxcl/homebrew/commits/master/Library/Formula/zsh.rb
==> Dependencies
Required: gdbm, pcre
==> Options
–disable-etcdir
Disable the reading of Zsh rc files in /etc
==> Caveats
To use this build of Zsh as your login shell, add it to /etc/shells.
If you have administrator privileges, you must fix an Apple miss
configuration in Mac OS X 10.7 Lion by renaming /etc/zshenv to
/etc/zprofile, or Zsh will have the wrong PATH when executed
non-interactively by scripts.
Alternatively, install Zsh with /etc disabled:
brew install –disable-etcdir zsh
Add the following to your zshrc to access the online help:
unalias run-help
autoload run-help
HELPDIR=/usr/local/share/zsh/helpfiles
To install zsh shell you can just in
$ brew install <package_name>
$ brew install zsh
You can make sure installation is completed and zsh is installed:
/bin/zsh
/Users/hadoopworld/Library/Logs/Homebrew/zsh
/usr/lib/zsh
/usr/lib/zsh/4.3.11/zsh
/usr/local/bin/zsh
/usr/local/Cellar/zsh
/usr/local/Cellar/zsh/5.0.2/bin/zsh
/usr/local/Cellar/zsh/5.0.2/lib/zsh
/usr/local/Cellar/zsh/5.0.2/share/zsh
/usr/local/lib/zsh
/usr/local/Library/LinkedKegs/zsh
/usr/local/opt/zsh
/usr/local/share/zsh
/usr/share/zsh
After the installation is completed you would need to download the config files which you can download directly from zsh git repo by cloning the repo to a specific folder. In the command below I am cloning zsh to my work folder, in its own folder name .oh-my-zsh.
$ git clone https://github.com/robbyrussell/oh-my-zsh.git ~/work/.oh-my-zsh
After clonOnce cloning is done you can change the shell for a specific using in your mac using chsh command used as below:
$ sudo chsh <desired_shell_binary> <user_name>
$ sudo chsh /usr/local/bin/zsh my_user_name
Now the last step to configure the zsh shell as you desired. First you would need to make sure that zsh shell resource configuration file is located in user home folder name .zshrc as below:
$ ls -lah ~/.zshrc
Next edit the .zshrc file to reflect the correct .oh-my-zsh location as below (In your case choose the correct folder where you have cloned the zsh shell config):
$ vi ~/.zshrc
Edit the path for correctness
# Path to your oh-my-zsh configuration.
ZSH=$HOME/work/.oh-my-zsh
You can also edit your choice of the these as below:
ZSH_THEME=”jonathan” ## “robbyrussell”
Finally source the shell to reflect the changes as below:
$ source ~/.zshrc
Thats all. You have zsh shell working with your terminal.
Time to time, i like to think outside the work and enjoy totally random stuff so I decided to learn more on Space-Time Crystal and collected the following:
A crystal or crystalline solid is a solid material whose constituent atoms, molecules, or ions are arranged in an ordered pattern extending in all three spatial dimensions. (more from wiki)
A space-time crystal or four dimensional crystal is a theoretical structure periodic in time and space. It extends the idea of a crystal to four dimensions (more from wiki)
We consider the possibility that classical dynamical systems display motion in their lowest energy state, forming a time analogue of crystalline spatial order. Challenges facing that idea are identified and overcome. We display arbitrary orbits of an angular variable as lowest-energy trajectories for nonsingular Lagrangian systems. Dynamics within orbits of broken symmetry provide a natural arena for formation of time crystals. We exhibit models of that kind, including a model with traveling density waves.
Read Full Paper here
Difficulties around the idea of spontaneous breaking of time translation symmetry in a closed quantum mechanical system are identified, and then overcome in a simple model. The possibility of ordering in imaginary time is also discussed.
Read Full Paper here.
Sometimes it becomes a need to find out particular module version in Python, here is the quickest way to find it:
Here is an example of finding pyCrypto (Module name – Crypto) version:
╚═╝ § python
Python 2.7.2 (default, Oct 11 2012, 20:14:37)
[GCC 4.2.1 Compatible Apple Clang 4.0 (tags/Apple/clang-418.0.60)] on darwin
Type “help”, “copyright”, “credits” or “license” for more information.
>>> import Crypto
>>> Crpto.__version__
Traceback (most recent call last):
File “<stdin>”, line 1, in <module>
NameError: name ‘Crpto’ is not defined
>>> Crypto.__version__
‘2.6’
>>> quit()
While working with Amazon EMR, it is possible that you might see an exception as below with your failed map/reduce task:
java.lang.Throwable: Child Error
at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:271)
Caused by: java.io.IOException: Task process exit with nonzero status of 137.
at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:258)
The potential problem in this case is that, the Hadoop mapper or reducer tasks are killed by Linux OS due to oversubscribing memory. Keen in mind that this issue Linux OOM killer and not the Java OOM Killer. In general such issue occurs when a particular process is configured to use lots more memory then the OS could provide and due to over memory subscription OS has no other way to kill the process.
With Amazon EMR such job failure could happen very easily if use have configured mapred.child.java.opts setting to way high comparative to specific EMR instance type. This is because each EMR instance type has preconfigured setting for Map and Reduce jobs and a misconfiguration could lead to this problem.
For example the EMR Instance type is m1.large which means it has 768 MB memory allocated for each Map or Reduce task in Hadoop job as below:
m1.xlarge
| Parameter | Value |
|---|---|
| HADOOP_JOBTRACKER_HEAPSIZE | 6912 |
| HADOOP_NAMENODE_HEAPSIZE | 2304 |
| HADOOP_TASKTRACKER_HEAPSIZE | 384 |
| HADOOP_DATANODE_HEAPSIZE | 384 |
| mapred.child.java.opts | -Xmx768m |
| mapred.tasktracker.map.tasks.maximum | 8 |
| mapred.tasktracker.reduce.tasks.maximum | 3 |
However in the mapred-site.xml if user setup the mapred.child.java.opts to way high value i.e. 8GB as below:
<property>
<name>mapred.child.java.opts</name>
<value>-Xmx8192m</value>
</property>
The above configuration would cause Linux OS to kill Mapper or Reduce task due to very high memory subscription. Linus OS will kill the same process even when it is configured to use 4GB also because it is way over the configured limit.
The solution to this problem is to let your job use default mapreduce settings instead setting by your self during the job submission. Using default mapreduce setting helps jobtracker to run the task under whatever settings Amazon EMR instance already have configured.
Once I have written a blog entry and shared through LinkedIn, LinkedIn has a new way to visualize how my article is viewed within my inner and extended LinkedIn circle. Here is an example:
First LinkedIn shows how my specific article is shared with others.
As displayed in the image below, you can see the blog has been views by 168 linkedIn users and 2 of them liked it. Those who liked the article are from two separate groups:
Now in the image below, you can see who from my direct contact view and liked the article:
Next as shows in the image blow you can see who from my extended circle liked and views the article:
Finally you can see more….
