Overview

Prerequisites

• Kubernetes
• Kubectl
• Shared Persistent Storage - Option are GlusterFS , Ceph FS, AWS EBS, AzureDisk etc.
• Java Application Source Code
• Dockerfile
• Container-Registry

• Private Docker Hub
• AWS ECR
• Docker Store
• Google Container Registry

Creating a Dockerfile

FROM maven:3-alpine

MAINTAINER XenonStack

# Creating Application Source Code Directory
RUN mkdir -p /usr/src/app

# Setting Home Directory for containers
WORKDIR /usr/src/app

# Copying src code to Container
COPY . /usr/src/app

# Building From Source Code
RUN mvn clean package

# Setting Persistent drive
VOLUME ["/data"]

# Exposing Port
EXPOSE 7102

# Running Java Application
CMD ["java", "-jar", "target/<name of your jar>.jar"]

Building Java Application Image

$ docker build -t <name of your java application>:<version of application>



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Overview

TDD (Test Driven Development)

• Firstly, add a test.
• Run all the tests and see if any new test fails.
• Update the code to make it pass the new tests.
• Run the test again and if they fail then refactor again and repeat.

BDD (Behaviour Driven Development)

• Explained the behaviour of the software/program.
• User friendly

What is Unit Testing?

What is Integration Testing?

Test Driven Development Workflow

• Write a concise, minimal test for a new piece of functionality. This test will fail since the functionality isn’t implemented yet (if it passes one knows that the functionality either already exists or that the test isn’t designed correctly).
• Implement the new functionality and run all tests, both the new and pre-existing ones. Repeat until all tests pass.
• Clean up the code and ensure that all tests still pass, then return to step 1.

Test First Development in Agile

• For this programming approach we write the tests before programming and during testing for functionality, all these test cases are run whenever we test the functionality.
• For test first programming we can also say that we are going to write the automated test cases before the functionality and the developer has to write the test case to satisfy these tests cases.

Test Driven Development

• Firstly when we go to design or implement a new feature we check whether an existing design is the best design which will help us to implement a new functionality.
• If the above condition satisfies then we follow the TFD approach for the implementation of new functionality.

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 What is a decentralized application?

Features of Decentralized applications

• Open Source: The application’s code structure must be mostly available for public research.
• Decentralized: The application’s data should be stored on a public and decentralized blockchain platform.
• Incentive: The application must utilize tokens/digital resources to reward its network supporters.
• Protocol: The application must generate tokens using a cryptographic consensus algorithm to demonstrate proof of value.

Building Decentralized Applications

Publish White Paper on the DApp

Gather Community

Begin Development

Launch the Product

Overview

What is BlockChain Technology?

Key Applications of BlockChain

• Capable of transforming
• Making transaction faster
• Reducing cost
• More security
• Transparency
• Seamless and simultaneous integration of transaction
• Settlements and ledger updates directly between multiple parties
• Creates a secure way to share information
• Conduct transactions without the need for a single, central party to approve them.
• Only authorized network members can see details of their transactions, providing confidentiality and privacy.
• All updates to the shared ledger are validated and recorded on all participants shared ledgers, which drives security and accuracy.
• All updates to the ledger are unchangeable and auditable. Network members can accurately trace their past activity.

How Does BlockChain Works?

How Bitcoin Transaction Works?

Building Blocks With BlockChain

Concept of BlockChain Technology

• Shared View - One of the most powerful features of BlockChain Technology is it’s shared a view of data for all participants in a peer-to-peer network. Transaction records can be shared but cannot be altered. Shared views have two approaches i.e. Traditional Approach where each party maintains their own independent ledger and Blockchain Approach where all parties share and maintain the same ledger.
• Cryptography - Cryptography is used to establish identity and protect the integrity of the underlying data. One of its concepts is hashing and this concept is used in the blockchain technology. Hashing is an effective means of determining if any piece of data has been changed or not. It generates a fingerprint for a piece of data by applying a cryptographic function to it. Changing one character in the original string results in a completely different hash value. Also, the original string cannot be reverse engineered from the hash function.

CryptoCurrency - Everything You Need to Know

Benefits of CryptoCurrencies

• No Fraudulent activities - Transactions happening in this process cannot be reversed or in any other way be tampered with, without at least letting anybody know. The whole architecture is such that any discrepancies cannot go unnoticed and can be detected.
• Faster transactions - The traditional way of settling payments involves a trusted third party, namely banks mainly, this makes the process take more time. In cryptocurrency, since the payments are peer-to-peer without any involvement of a third party, the payment process happens immediately without any delay. No Overheads- With the elimination of third party involvements, the overheads in the form of service fees that these institutions charge are also eliminated. This makes cryptocurrencies more cost-effective.
• The integrity of identity - Unlike credit cards, which always have a risk of getting misused since all the information regarding it is given to the vendor, this mode of payment does not divulge any more information than required and only pushes the amount of money that is required to be paid.

How is Blockchain Changing Money and Business?

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Docker Ecosystem

Docker Platform

Docker Container Components

Docker Engine

• A server which is a continuously running service called a daemon process.
• A REST API which interfaces the programs to use talk with the daemon and give instruct it what to do.
• A command line interface client.

Docker Daemon

Docker Client

Docker Images

Docker Registries

Docker Containers

Namespaces

• Namespace PID provides isolation for the allocation of the process, lists of processes with details. In new namespace is isolated from other processes in its "parent" namespace still see all processes in child namespace
• Namespace network isolates the network interface controllers, IP tables firewall rules, routing tables etc. Network namespaces can be connected with each other using the virtual Ethernet device.

Control Groups

Union File Systems

Container Format

Docker File

• FROM - This is used for to set the base image for the instructions. It is very important to mention this in the first line of docker file.
• MAINTAINER - This instruction is used to indicate the author of the docker file and its non-executable.
• RUN - This instruction allows us to execute the command on top of the existing layer and create a new layer with the result of command execution.
• CMD - This instruction doesn’t perform anything during the building of docker image. It Just specifies the commands that are used in the image.
• LABEL - This Instruction is used to assign the metadata in the form key-value pairs. It is always best to use few LABEL instructions as possible.
• EXPOSE - This instruction is used to listen on specific as required by application servers.
• ENV - This instruction is used to set the environment variables in the Docker file for the container.
• COPY - This instruction is used to copy the files and directory from specific folder to destination folder.
• WORKDIR - This instruction is used to set the current working directory for the other instruction, i.e., RUN, CMD, COPY, etc.

Docker Architecture

Key Features Of Docker

• Docker allows us to faster assemble applications from components and eliminates the errors which can come when we shipping the code. For example, we can have two Docker containers running two different versions of the same app on the same system.
• Docker helps us to test the code before we deploy it to production as soon as possible.
• Docker is simple to use. We can get started with Docker on a minimal Linux, Mac, or Windows system running with compatible Linux kernel directly or in a Virtual Machine with a Docker binary.
• We can "dockerize" our application in fewer hours. Mostly Docker containers can be launch with in a minute.
• Docker containers run everywhere. We can deploy containers on desktops, physical servers, virtual machines, into data centers, and up to public and private clouds. And, we can run the same containers everywhere.