Author Archives: Ajitesh Kumar
Kubernetes – Practice Test / Interview Q&A on Service Discovery
This article represents concepts, revision / quick notes, and practice or sample test/interview questions and answers on Service Discovery topic of Kubernetes. These notes, Q&A could provide to be helpful for those appearing for Kubernetes administrator certification exams (CKA). Revision Notes – Service Discovery Kubernetes supports the following two modes of service discovery: Environment variable DNS Service environment details can be set based on the following format. Service name needs to be in uppercase. {SVCNAME}_SERVICE_HOST {SVCNAME}_SERVICE_PORT When using environment variables for service discovery, it is a mandate that the services must be created prior to the pods which want to access those services. DNS server creates a set of records for each service discovered via watching Kubernetes APIs. Services of type ExternalName can only be accessed …
Hyperledger Fabric Transaction Flow (Interview Q&A & Notes)
This article represents concepts in relation to, how does a transaction flow in Hyperledger Fabric Blockchain network, in form of notes and interview questions and answers. Those appearing for Hyperledger Fabric interview would find the questions and notes very useful for quick brush-up. Hyperledger Fabric is a platform for distributed ledger solutions. The following represents key participants in Hyperledger Fabric Blockchain network who are involved in the transaction flow right from the initiation of transaction proposal to committing a transaction into the distributed ledger. Application: Gets involved in following capacity: Sends the transaction proposal to endorsing peers Receives the transaction results from endorsing peers Broadcasts the transaction message to ordering service Endorsing peers: Do some of the …
Angular – How to Search or Filter Table by Column
This article represents concepts and code samples in relation to filtering or searching table by one or more column data when working with Angular (Angular 2.*, Angular 4.* Angular 5.*). One can achieve the search/filter table by column functionality by creating custom pipes. Although Angular recommends it by handling the logic in services, one can always create custom pipes as shown in this article. The following topic is discussed later in this article: No Out-of-box support for Filter or OrderBy in Angular How to create search filter for filtering table by column The details on creating custom pipes can be read from this page, Angular Pipes. No Out-of-box support for Filter or OrderBy in Angular Unlike AngularJS, …
Spring Boot & Angular App Hello World as One Deployable War
This article represents steps and related code samples to deploy an Angular app (created with Angular 2.*, Angular 4.* or Angular 5.*) with a Spring Boot / Spring Web app as one deployable unit (war file) on the web server such as Tomcat, Jetty etc. Different Deployment Strategies for Spring Boot and Angular App The following are the two different strategies which can be used for deploying web app built with Angular 5.* (and previous versions such as Angular 4.* or Angular 2.*) used for doing client side programming and Spring boot with Spring Web for server-side programming. Deploy Angular App and Spring Boot / Spring Web app as different applications running on different servers; This implies that users connect …
Hyperledger Fabric Distributed Ledger – Interview Questions / Notes
This article represents practice test / interview questions and answers and revision notes on Hyperledger Fabric Distributed Ledger**. These questions and answers can prove to be very helpful to check your knowledge on Hyperledger Fabric if you are appearing for Hyperledger Fabric interview in near future. Hyperledger Fabric is an open-source framework for building distributed ledger solutions. The distributed ledger is maintained by every peer participating in the network. It is stored as a combination of a transaction logs and a world state database (key-value pairs). Revision Notes – Hyperledger Fabric Distributed Ledger Concepts The distributed ledger is a combination of following: Blockchain to store immutable ordered/sequenced records; It is stored in form of transaction logs and stored in peers’ file system (local …
Hyperledger Fabric – Difference between World State DB & Transaction Logs
This article highlights key differences between World State Database (DB) and Transaction Logs which comprise the Hyperledger Fabric Distributed Ledger. Hyperledger Fabric Distributed Ledger can be said to be a combination of World State Database (DB) and transaction logs. It requires invocation of chaincode (smart contracts) for interacting with distributed ledgers (world state DB and transaction logs). The transactions are stored in the block in the same sequence in which they occured and this is responsibility of ordering service to ensure the ordering sequence of transactions in the block. World State Database Transaction Logs Stores the chain’s state information in form of key-value pairs Stores chain of blocks consisting of transaction details in form of sequence of transactions Stored in database such as LevelDB …
Hyperledger Fabric Introduction – Interview Questions / Revision Notes
This article represents practice test and revision notes on Introduction to Hyperledger Fabric. These questions and answers can prove to be very helpful to check your knowledge of Hyperledger Fabric if you are appearing for Hyperledger Fabric interview in near future. Hyperledger Fabric is an open-source framework for building distributed ledger solutions. The unique thing about Hyperledger Fabric is that it supports pluggable implementations of different components such as identity management, consensus algorithm etc. Revision notes on Introduction to Hyperledger Fabric Hyperledger Fabric can be used for creating private and permissionless Blockchain network. Blockchain Participants – Membership Members join Hyperledger Fabric Blockchain network using Membership Service Provider (MSP) service. Hyperledger Fabric allows custom MSP to be plugged. Distributed Ledger – Data and Database Hyperledger Fabric allows ledger data to be stored …
QISKit and IBM-QX for Running Quantum Computing Applications
IBM-Q is IBM’s initiative to build commercially available universal quantum computers for business and science. IBM-Q currently recommends using QISKit and Quantum Composer for building quantum computing experiments, programs and applications which could run on real quantum computing hardware provided by IBM cloud. The details on how to get started with building and running Quantum applications can be provided on IBM’s website, IBM Q Experience (IBM-QX). In this article, let’s look at further details in relation with QISKit SDK. QISKit SDK for building Quantum Computing applications IBM-Q recommends Python software development kit (SDK) namely Quantum Information Software Kit (QISKit) which can be used for building programs, applications that could run on IBM quantum computers (quantum computing hardware). Here are some reference links: Github page on QISKit: COnsists …
Certified Kubernetes Administrator Sample Test on Services Concept
This page represents practice test consisting of questions and answers on Kubernetes. This practice test covers the topic such as Kubernetes Services. The practice test can prove to be very helpful if you are preparing to take Certified Kubernetes Administrator (CKA) certification examination in near future. It covers the Networking Concepts from CKA certification exam syllabus which can comprise of 11% questions in CKA certification exam. Check out other question sets on this page, Kubernetes Certification Exam (CKA) Sample Questions Sets. Revision Notes – Kubernetes concepts on Services A Kubernetes service is an abstraction which is used to define a logical set of pods. A Kubernetes service is assigned an IP address. In service spec definition, port refers to incoming port which is mapped to targetPort on Pod. By default, the value of …
Kubernetes Certification Exam (CKA) Sample Questions Sets
This article represents a series of practice / sample tests on some of the following topics as per the Kubernetes CKA exams syllabus. Kubernetes certification expert page also provides weightage associated with different topics. Topics Weightage Application Lifecycle Management 8% Installation, Configuration & Validation 12% Core Concepts 19% Networking 11% Scheduling 5% Security 12% Cluster Maintenance 11% Logging / Monitoring 5% Storage 7% Troubleshooting 10% These questions are intended to provide you with practice tests to test your knowledge on different Kubernetes concepts before appearing for Kubernetes certification (CKA) exams. This page will be updated from time-to-time as more practice tests are added. Practice / Sample Tests on Kubernetes Topics …
Great Quantum Computing Tutorials from DWave System
I have been watching several quantum computing tutorial videos on YouTube and Ted, and, reading multiple web pages to find out one or more videos / documents which could make it easier for anyone to understand quantum computing and related concepts. This is where I landed on this document Quantum Computing Primer by DWave Systems. The following are some of the document highlights: Explained quantum computing concepts such as qubits being in superposition of states using light switches with ON and OFF states with reference to both classical and quantum computing. The following is the most interesting part of Qubits explanation: You start with the system in its quantum superposition …
Hyperledger Fabric Platform Components & Docker Images
This article represents details on installing / setting up Hyperledger Fabric Platform Components / Binaries with emphasis on some of the following: Steps for how to install / setup Fabric platform components & docker images Details on platform components which are used for setting up the Fabric network Details on docker images which comprise Hyperledger Fabric network The installation leads to download /pull of docker images which are required to run the Blockchain network using Hyperledger Fabric. Installing Fabric Platform Components & Docker Images The following command can be used to install Platform binaries: In case Docker commands require sudo, the above command looks like following: The script which gets …
Hyperledger Tools – When / Why to use them?
This article aims to present details on when and why to use which Hyperledger tools. The following are different tools which are referred later in this article: Cello Composer Explorer Quilt This article will be updated on regular basis as newer tools come up. When / Why to use which Hyperledger Tools? The following represents details related with the Hyperledger tools: Hyperledger Tools When and Why to use them? Explorer Hyperledger Explorer is a web application which can be used to view, invoke, deploy or query blocks, transactions and associated data, network information (name, status, list of nodes), chain codes and transaction families, as well as any other relevant information stored in the …
Kubernetes Interview Questions and Answers – Set 4
This page represents practice test consisting of objective questions and answers on Kubernetes. This practice test covers the topic such as Pod Lifecycle. The practice test can prove to be very helpful if you are preparing to take Certified Kubernetes Administrator (CKA) certification examination in near future. It covers the Core Concepts from CKA certification exam syllabus. Those preparing for interviews in relation with Kubernetes or cloud-native apps would also find these questions to be useful enough. These questions can as well prove to be useful for interns / freshers / beginners. Revision Notes – Kubernetes Concepts (Pod Lifecycle) A Pod status field is a PodStatus object which has got phase field. The phase of the pod is a simple, high-level summary of where the Pod is in its lifecycle Kubelet invokes …
Beginners – List of Robotics Courses to Get You Started
The following is the list of Robotics Courses on Coursera which will help you get started on learning Robotics concepts. Robotics Specialization:It is a series of six courses on Robotics covering the concepts related to some of the following areas: Robot flight and movement How do robots perceive their environment How do robots adjust their movements to avoid obstacles, navigate difficult terrains and accomplish complex tasks such as construction and disaster recovery. This is provided by University of Pennsylvania. The following is a list of courses covered under the umbrella of Robotics specialization: Aerial Robotics Computational model planning Mobility Perception Estimation and learning Building Arduino robots and devices: It covers concepts related with building robots using …
Quantum Computing Interview Questions and Answers – Set 1
This is the first in series of practice tests / interview questions and answers in relation to Quantum computing. It touches upon the basic concepts in relation to some of the following: Qubit Difference between a bit and Qubit Superposition of Qubit states Quantum entanglement This practice test will prove to be useful for Quantum Computing beginners / interns / freshers. Revision Notes – Quantum Computing Fundamentals Quantum computing is different than classical computing. Problems which are suited for quantum computing should be considered for Quantum computing. A Qubit is a two-state quantum mechanical system; A Qubit can be in superposition of both the states at the same time. A Qubit is similar to bit …
I found it very helpful. However the differences are not too understandable for me