Author Archives: Ajitesh Kumar

Ajitesh Kumar

I have been recently working in the area of Data analytics including Data Science and Machine Learning / Deep Learning. I am also passionate about different technologies including programming languages such as Java/JEE, Javascript, Python, R, Julia, etc, and technologies such as Blockchain, mobile computing, cloud-native technologies, application security, cloud computing platforms, big data, etc. For latest updates and blogs, follow us on Twitter. I would love to connect with you on Linkedin. Check out my latest book titled as First Principles Thinking: Building winning products using first principles thinking. Check out my other blog, Revive-n-Thrive.com

Dockers – Top 5 Use Cases for Dockers Adoption

This blog represents top 5 use cases why IT enterprises (product & software-service vendors) should consider adopting Dockers in their SDLC. 1. Quicker Developer Onboarding into Projects: We all are aware of development environment setup related issues when taking about developers on boarding. In my recent experience, I almost spent a week to get manually setup for a recently started project comprising of just 3-4 members. I had to refer to couple of documents which was last updated few weeks back and thus was not up to date. This led to productivity loss. In my earlier experience, I saw the usage of VMs images for developer onboarding. This worked very …

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Posted in Dockers, Software Engg, Virtualization. Tagged with , .

ReactJS – Step-by-Step Tutorial on Quiz Development

I just finished up writing a simplistic/trivial framework using ReactJS using which one could quickly create online quizzes. The code for this could be found on github on following page named as ReactJS-Quiz. I would like to take this opportunity to share AngularJS-Quiz  that I wrote sometime back. I must say that I found writing quiz framework using ReactJS more fulfilling as it got aligned to my OOP oriented thinking and I was not required to envisage templates etc as in case of AngularJS. That said, both frameworks are cool and have their own pluses and minuses. Please feel free to suggest if I missed on mentioning one or more …

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Posted in Javascript, Web. Tagged with , .

ReactJS – What is this.props.items.map Property?

This article represents concepts around usage of “map” method to traverse and display list of similar objects representing a component in ReactJS. The title represents “this.props.items.map”, although it could be anything such as “this.props.profiles.map” like in examples below where profiles or items represent an array. It could be used to create a list, table etc. Please feel free to comment/suggest if I missed to mention one or more important points. Also, sorry for the typos. Following are the key points described later in this article: Map is NOT a feature of ReactJS Code Sample – Usage of “map” as in this.props.profiles.map Map is NOT a feature of ReactJS After looking …

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Posted in Javascript, Web. Tagged with , .

5 Reasons Why Every Developer Must Adopt Dockers

This blog represents my thoughts on why every developer must adopt dockers for their day-to-day development purpose. I got introduced to Dockers technologies a couple of months back and trust me, I have started wondering on how I have been developing/coding prior to that.  Honestly speaking, I am floored. Here are some of the top reasons why you should also give a shot to Dockers. Bring up Dev Environment in No Time One of the issue that I faced in the programming/development experience is living with same Dev environment through out the entire development cycle for months all together. At times, due to installation of software updates, the environment used …

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Posted in Virtualization. Tagged with .

ReactJS – How to Configure Sublime TextIDE for Faster Development

This article represents instructions on how to configure your existing Sublime Text Editor for faster development. Please feel free to comment/suggest if I missed to mention one or more important points. Also, sorry for the typos. Following are the instructions: Install the Package Control within your Sublime TextIDE. Follow instructions on package control page. Pay attention to tabs comprising of different information for Sublime Text 2 and Sublime Text 3 edition. Once done, Type ctrl+shift+p on Windows and it opens up a command palette. Type React, select ReactJS That is it! You could open up a file, save it as *.js, and type rcc. It would print class creation template …

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Posted in Javascript, Web. Tagged with .

NodeJS – How to Develop Javascript using Console (Node)

This article represents tips on how to do Javascript programming using Console with the help of NodeJS. Please feel free to comment/suggest if I missed to mention one or more important points. Also, sorry for the typos. Following are the key points described later in this article: Setting up NodeJS Environment Program Hello World & Execute on Console Setting up NodeJS Environment I recommend using Docker environment for setting up the NodeJS environment. Using that you could work on CentOS and NodeJS and make bets use of NodeJS. Follow the instructions on following page, Dummies Notes – Get Started with Docker Hello World to setup the Docker environment. Recently, Docker …

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Posted in Javascript, Web. Tagged with , .

How to Migrate from Boot2Docker to Docker Toolbox

This article represents quick information on how to migrate existing Boot2Docker containers and images to newly launched Docker Toolbox, that was officially announced on this Docker’s blog. Please feel free to comment/suggest if I missed to mention one or more important points. Also, sorry for the typos. Following are the key points described later in this article: What is Docker Toolbox? Migration to Docker Toolbox What is Docker Toolbox? With the development community talking about issues related with getting up and started with Dockers and need for one-click install of Docker, Docker finally came out with something called as Docker Toolbox. This comes with following: Docker client Docker kitematic Docker …

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Posted in Virtualization. Tagged with .

Dummies Notes – How to Setup Oracle Data Guard

This article represents instructions which could be used to set up oracle data guard on a primary and one or more physical standby database. The article presumes that you have a basic understanding of what is Oracle Data guard and why it needs to be set up. Following are key aspects which are discussed later in this article: Primary Database Setup Physical Standby Database Setup Following is details on primary and physical standby database setup: Primary Database Setup: Configure the primary database appropriately including doing some of the following: Enable force logging Alter the database parameters such as following. This is one time activity and does not needed to be …

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Posted in Database. Tagged with , .

Docker – How to Install NodeJS on Docker

This article represents quick instructions on how to install NodeJS on CentOS Docker Image. The detailed instructions of installing NodeJS on linux could be found on this page. Please feel free to comment/suggest if I missed to mention one or more important points. Also, sorry for the typos. Following is the set of instructions: Install the docker on your machine. Pull the Centos docker image Create a container using the Centos docker image. Following command could be used: docker run -ti -dP –name centos -v /c/Users:/mnt/Users centos:latest /bin/bash Start the docker container and attach. Following command can be used: # Starts the docker container docker start centos # Attach docker …

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Posted in Javascript, Virtualization. Tagged with .

RPM – How to Build RPM Package

This article represents tips to build RPM package using rpmbuild command. Please feel free to comment/suggest if I missed to mention one or more important points. Also, sorry for the typos. Following are the key points described later in this article: Install RPMBuild Package Instructions to Create RPMs Install RPMBuild Package Make sure that rpmbuild exists. Type rpmbuild in command line and confirm that usage text appears. In case, rpmbuild does not exists, download it using command, “yum -y install rpm-build” Instructions to Create RPMs Create a top level folder such as “rpmbuild” within home directory. Go to rpmbuild folder using command such as “cd rpmbuild” Create following folder within …

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Posted in IT Automation. Tagged with .

Docker – How to Install NodeJS on Docker

This article represents quick instructions on how to install NodeJS on CentOS Docker Image. The detailed instructions of installing NodeJS on linux could be found on this page. Please feel free to comment/suggest if I missed to mention one or more important points. Also, sorry for the typos. Following is the set of instructions: Install the docker on your machine. Pull the Centos docker image Create a container using the Centos docker image. Following command could be used: docker run -ti -dP –name centos -v /c/Users:/mnt/Users centos:latest /bin/bash Start the docker container and attach. Following command can be used: # Starts the docker container docker start centos # Attach docker …

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Posted in Virtualization. Tagged with .

ReactJS – Controlled Component Code Example

This article represents code sample for ReactJS UI controlled components along with related details. Please feel free to comment/suggest if I missed to mention one or more important points. Also, sorry for the typos. The code sample represents an input field consisting of “Calvin”. Once you change the text, the “calvin” written with “Hello” would also change. Following are the key points described later in this article: What are controlled components? Code Example – Controlled Component What are Controlled Component? As per the ReactJS Form page, An <input> with “value” set is a controlled component. In a controlled <input>, the value of the rendered element will always reflect the value …

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Posted in Javascript, Web. Tagged with , .

ReactJS – How to Think & Program Hello World – Part 1

This article represents Hello World example in ReactJS with explanation on how one could think in component-oriented manner when working with ReactJS. Please feel free to comment/suggest if I missed to mention one or more important points. Also, sorry for the typos. Following are the key points described later in this article: Hello World Code Sample Thinking & Programming Hello World Hello World Code Sample Paste the code below in an HTML file and open up in a browser. The text, “Hello, Calvin” will get printed. <!DOCTYPE html> <html> <head> <title>Hello ReactJS!</title> <script src=”https://cdnjs.cloudflare.com/ajax/libs/react/0.13.3/react.js”></script> <script src=”https://cdnjs.cloudflare.com/ajax/libs/react/0.13.3/JSXTransformer.js”></script> </head> <body> <div id=”content”></div> <script type=”text/jsx”> var HelloMessage = React.createClass({ render: function() { return …

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Posted in Javascript, Web. Tagged with , .

Docker – How to SSH to Running Container

This article represents instructions on how you could get a docker container connect with other docker container using SSH. Please feel free to comment/suggest if I missed to mention one or more important points. Also, sorry for the typos. Following are the key points described later in this article: Instructions to Install SSH Techniques to Enable SSH on the Existing Container Techniques to SSH to Running Container Instructions to Install SSH If you already have a running container, and you would like to put SSH on it and allow other docker container to connect via SSH, following is a set of instructions to install SSH: ## ## Install the openssh-server …

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Posted in Virtualization. Tagged with , .

AngularJS – Two Different Ways to Bind Model Data to HTML Element

This article represents two different techniques using which application data (model) could be bound to HTML element in AngularJS. Either of the technique is used to replace the text content of the specified HTML element with the value of a given expression, and to update the text content when the value of that expression changes. Please feel free to comment/suggest if I missed to mention one or more important points. Also, sorry for the typos. Following are the key points described later in this article: Bind data using {{ expression }} syntax Bind data using ng-bind directive Recommended way of binding data Bind Data using {{ expression }} Syntax Following …

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Posted in Javascript, Web. Tagged with , .

How to Install Oracle 11g (EE) on Docker

This article represents instructions on how to install & configure Oracle 11g Database (Enterprise Edition) on Docker. Well, I could have lived with installing Oracle 11g express edition, had I have the requirement of testing my application with Oracle database for single user. The primary reason for installing Oracle enterprise edition was to test the high availability using Oracle Data Guard solution. As we may knowing that Oracle Data Guard does not come with Oracle XE Database, thus, it becomes mandatory to work with Oracle EE Database edition which comes bundled with Data Guard solution. The primary challenge in installing Oracle EE database on Docker is the disk space problem …

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Posted in Virtualization. Tagged with , , .