Wallet Software

Wallet Software :

A cryptocurrency wallet is a software program that stores your private and public keys using which it interacts with various blockchain to enable users to send and receive their cryptocurrency and monitor their balance. If you want to use Bitcoin or any other cryptocurrency, you will need to have a digital wallet.

When a person sends you any digital currency, they are essentially transferring ownership of the coins to your wallet’s address. In order to transfer those coins, the private key stored in your wallet must match the public address the currency is assigned to. If public and private keys match, the balance in your digital wallet will increase, and the senders wallet will decrease accordingly. There is no actual exchange of real coins. The transaction is signified merely by a transaction record on the blockchain and a change in balance in your cryptocurrency wallet.

Desktop: wallets are downloaded and installed on a PC or laptop. They are only accessible from the single computer in which they are downloaded.

Online: wallets run on the cloud and are accessible from any computing device in any location. While they are more convenient to access, online wallets store your private keys online and are controlled by a third party which makes them more vulnerable to hacking attacks and theft.

Mobile: wallets run on an app on your phone and are useful because they can be used anywhere including retail stores.

Examples : Apple pay, Google wallet and Samsung pay.

Here is how a bitcoin transaction is processed:

1) Payers initiate a bitcoin payment using “wallet” software.

2) This and other pending transactions are broadcast on the global bitcoin network.

3) Once every ten minutes or so, “miners”, specialised computers (or groups of computers) on this network, collect a few hundred transactions and combine them in a “block”.

4) In order to mine a block and validate the transaction, miners compete to solve a difficult mathematical equation (a “hash function”). The miner that solves the equation first further processes the block and broadcasts this “proof-of-work” to the bitcoin network.

5) The other miners check the proof-of-work and the validity of the transactions. If they approve, the winning miner gets a reward of 25 newly minted bitcoin (about $6,900 at current prices), which is the incentive for miners to provide computing power. Adjusting the difficulty of the puzzle ensures that the supply of new bitcoins remains steady.

6) The mined block is added to the “blockchain”, a big, unbreakable ledger that lives on the bitcoin network and serves as a record of all transactions.

7) The payee can use his wallet software to see whether the bitcoin have arrived.

External links
Walletgenerator.net – Offers various methods to create private key to store and do transaction for the Ethereum wallet.

https://www.myetherwallet.com/ – GUI based system to manage Cryptocurrency like Bitcoin, Ether – Able to transfer/receive funds and much more.

Evolution of Cryptocurrency & Blockchain technologies in India

The year 2017 has been particularly interesting for the growth of cryptocurrencies in India. The people of India and the Indian market for cryptocurrencies appear to love them all the more. Now lets see how the cryptocurrencies and blockchain technology will emerge in near future in India.

JIO Coin :

Reliance JIO Planning to launch their own cryptocurrency because of Present trend Across World wide. The name for this cryptocurrency is Jio Coin, and this will help the customers to make digital payments very more comfortable.

According to latest News, JIO Launching JIO Coin very soon. For this jio coin ico project Mukesh Ambani’s elder son Akash Ambani taking leading for the Reliance Jio Coin project officially, Reliance Jio planning to build a 50-member team of young professionals to work on blockchain technology, which can also be used to develop applications such as smart contracts and supply chain management logistics.

What Will Be The Jio Coin Price In India ?

There are many rumors on the context of Jio Coin Price in India but still there is no any official announcement of jio coin. But as per the popularity of Jio, the expected price of the JIO coin is 1$ which equals to Rs 64 approximately in Indian currency.

How To Buy JIO Coins Online In India With INR & USD ?

As per the reports, Reliance Jio may launch their cryptocurrency on JioMoney app in which you will be able to buy Jio Coins Online using your wallet balance. But after few days, it might become available for purchase on popular exchanges like Bittrex, Binance, Koinex.

Blockchain in Banks:

As of 2017, 60% of financial organizations plan on using blockchain for international money transfers, security clearing and settlement and anti-money laundering services.

Two primary reasons that blockchain technology is going to revolutionize the banking industry in the next decade.

  • It’s far less expensive.
  • Transactions are significantly faster.

Blockchain would enable higher security and lower costs for banks to process payment between organizations and their clients and even between banks themselves. In the current reality, there are a lot of intermediaries in the payment processing system, but blockchain would eliminate the need for a lot of them. By using the proof of concept, blockchain was able to complete the transactions in just 10 to 20 seconds.

There’s a lot of paying fees and waiting for money transfers. Fees for Money transactions average around 10%, and the money transfer takes about one to two business days. Financial institutions spend a large amount just to keep up with KYC regulations.

For instance, blockchain technology would potentially remove any overhead costs for customer identification.  In a distributed ledger system, the customer identification is effectively performed by everyone on the network, simultaneously.

Most banking systems around the world are built on a centralized database that is more vulnerable to cyber-attack because it has one point of failure rather than many—once hackers breach the one system they have full access.

The blockchain is essentially a distributed ledger where each block contains a timestamp and holds batches of individual transactions with a link to a previous block. This technology would eliminate Fraud transactions.

Blockchain in SBI :

State Bank of India (SBI) will go in for full-fledged deployment of blockchain in its reconciliation, remittances and trade finance operations in FY19.

In February 2017, Bankchain, a consortium of banks led by SBI, was set up to work on developing blockchain-based solutions for banking in India. BankChain is a community of 27 banks from India and the Middle East. BankChain aims to reduce fraud and maximize efficiency, security & transparency in the banking systems.

Primechain Technologies operates the BankChain community  will deliver an enterprise blockchain solution that runs on Hyperledger Sawtooth and Intel Software Guard Extensions (Intel SGX).

The solution will help SBI to increase the efficiency of financial transactions without having to compromise on data confidentiality and transaction security.

Benefits of blockchain technology for banks :

The key benefits of blockchain technology for banks :

  • Less Expensive
  • Greatly improved security
  • Reduced infrastructure cost
  • Greater transparency and auditability
  • Real-time automated settlement.

How to Improve your site’s rating?

Before entering the SEO techniques You need to do an SEO Audit on your website.

Complete an SEO Audit on your website

Auditing your website helps you discover why you’re not getting enough search traffic and sales. An SEO audit means you’re closely examining your overall site performance, setting new goals based on what you find, and implementing tactics to reach those goals.

Check #1: Do all your website’s pages have SEO meta titles and descriptions?

Check #2: Is each page on your website optimized for SEO keywords?

Check #3: Is your URL structure optimized for search engines? Your URLs should be simple, short, and easy for a search engine to tell what the page is about.

After Completing your SEO Audit You can implement the below given SEO techniques one by one.

1. Improve User Engagement on sites

2. Lowering your Bounce Rate

3. Improve Site Speed

4. Reduce redirects

5. Research Keywords and Use Them Sparingly

6. Youtube SEO

7. Make a Strong Presence on Social Media

8. Update and republish old blogs

9. Build Backlinks

10. Don’t forget about bing & yahoo

Improve User Engagement on sites

Engagement is the ability to hold a user’s attention. In SEO terms, it is a measure of the amount of time spent on a page.

Here are the factors that determine Your page ranks : Search Visits, Direct Visits, Total Visits, Page views, Time on site, Bounce Rate.

Since Google only wants to deliver the best possible results to its users, it will push sites with strong engagement up in the search engine results pages.

Good formatting can improve your page’s readability. Use shorter paragraphs, shorter sentences, and bullet points so that your page’s content looks attractive to the readers.

Lowering your Bounce Rate

Bounce rate is the percentage of visitors who land on your website and leave without interacting further. One reason that your target customers might leave your site is a lack of readability. Maintaining & improving Your content’s readability will reduce the bounce rate.

Avoid irrelevant popups, users may found that to be annoying. If the landing page does not satisfy the visitor’s are going to bounce the moment they arrive on your website.

Improve Site Speed

Page speed is often confused with “site speed”, Page speed can be described in either “page load time” (the time it takes to fully display the content on a specific page). Pages with a longer load time tend to have higher bounce rates and lower average time on page.

Reducing the size of your CSS, HTML, and JavaScript files that are larger than 150 bytes can improve you page speed.By optimizing your code (including removing spaces, commas, and other unnecessary characters), you can dramatically increase your page speed.

Reduce redirects

There are many common reasons to have redirects. You should know the performance and speed problems they create and how to solve them. As more and more people use mobile, redirects will become more and more of a problem.

There are many good and legitimate reasons to have redirects but it should be kept in mind that redirects cause significant performance and speed issues. Every single redirect you can remove (or clean up) will make your pages load faster.

Research Keywords and Use Them Sparingly

Keywords are one of the main elements of SEO. SEO keywords are the key words and phrases in your web content that make it possible for people to find your site via search engines.

Instead of thinking in terms of individual keywords, think in terms of themes of keywords. A single page will be about a single topic, which can then be described with several keywords.

When you have several pages about specific topics, and they are all optimized for a theme of keywords, then your site as a whole is going to be relevant for not just a single keyword, but a full range of keywords.

All your keywords work together to tell the full story of your site. What is it about? How is it relevant? You want to use a single keyword theme per page to help Google understand exactly what each page is about and how it relates to the whole. Keep that concept in mind while you are trying to fit keywords and your site together.

Youtube SEO

Focusing on YouTube SEO will push your website onto the first page on Google and get you traffic from YouTube as well. The filename, the title, the description—all these elements affect your rankings. YouTube uses keywords in the description to rank you for super-long tail keywords. If you take the time to optimize your videos for SEO, you’ll get significantly more traffic than your competitors.

Make a Strong Presence on Social Media

Social can be utilized to build not only awareness but also brand authority. The more shares on social media you have, the more opportunities people have to see your content and link to it.

With the number of people on social media, its worldwide reach, and its ease of sharing, social media is a great way to build your web presence and quickly build an audience. You have to be proactive and reach people where they are.

Update and republish old blogs

If you’re not driving traffic to your old blog posts, you are slashing your ROI dramatically.It doesn’t make sense to spend lots of hours or hundreds of dollars creating a new blog post and then letting it die. Regularly share old content on social media. Regularly go back and add internal links to older posts.

You can’t just republish some posts, because they lose value over time.So you can create a completely new, updated post.

Build Backlinks

Building backlinks is still crucial for good rankings. “Backlinks,” meaning sites that link to your site, are, for most search engines, the supreme ranking factor. The more authoritative websites that link to you, the better rankings and traffic you’ll get.

The acceptable ways of link building are getting listed in directories, posting in forums, blogs and article directories.

You can get backlinks by guest posting on websites. Don’t overlook websites that don’t have a “write for us” page.You might wonder why sites as those, listed by the Backlink Builder tool provide such a precious asset as backlinks for free. The answer is simple – they need content for their site. When you post an article, or submit a link to your site, you do not get paid for this. You provide them for free with something they need – content – and in return they also provide you for free with something you need – quality backlinks. It is a free trade, as long as the sites you post your content or links are respected and you don’t post fake links or content.

Monitor the links from your guest posts. Use the Monitor Backlinks SEO tool for automatic updates and keep track of all your backlinks.

Don’t forget about bing & yahoo

The Internet world doesn’t revolve around google. There are still users who prefer Yahoo or Bing and some are just plain used to it. Understand that this requires you to adapt to the workings of the major search engines and develop your site accordingly. It is called Search Engine Optimization. Adjust your sites to match the working of these engines as well, to boost your SEO.

Installing Parity, Geth and configuring CentOS 7 to deploy a smart contract (using Ropsten testnet)

Installing Python 3.6 on CentOS 7

sudo yum install https://centos7.iuscommunity.org/ius-release.rpm

sudo yum install python36

python3.6 -V

After installing Python3.* version. it’s time to install PIP.

yum -y update

Then let’s install python-pip and any required packages:

yum -y install python-pip

There are many open source GIT projects to deploy smart contracts such as Zepplin(https://zeppelinos.org/), TokenmarketICO (https://github.com/TokenMarketNet/ico)
If you need a framework with absolute test cases, migrations. You should choose Truffle (http://truffleframework.com/)
Truffle is Ethereum framework where you can create a Smart contract, Compiling it and deploy it on testnet or testrpc. (Ganache)

In this tutorial, We will see deploying a smart contract using Tokenmarket ICO. Follow this link to install the Github contents and required libraries.

Set the environmental varial PKG_CONFIG_PATH
to check your pkg-config path using ‘whereis pkgconfig’ commmand and modify as per your installation.

export PKG_CONFIG_PATH=/usr/lib/pkgconfig

pip install –upgrade cffi

yum install python36-devel

yum install openssl-devel

Installing SOLC compiler

python3.6 -m solc.install v0.4.16

Installing Parity for CentoOS 7 

The following 2 commands should Install the Parity and its dependencies

$ bash <(curl https://get.parity.io -kL)

yum install openssl libssl-devel libudev-devel

Parity command to start the Ropsten node and sync with our server

parity -l 5 –chain ropsten –bootnodes “enode://20c9ad97c081d63397d7b685a412227a40e23c8bdc6688c6f37e97cfbc22d2b4d1db1510d8f61e6a8866ad7f0e17c02b14182d37ea7c3c8b9c2683aeb6b733a1@,enode://6ce05930c72abc632c58e2e4324f7c7ea478cec0ed4fa2528982cf34483094e9cbc9216e7aa349691242576d552a2a56aaeae426c5303ded677ce455ba1acd9d@” –rpccorsdomain “*” –unlock 0xe6bfd0a63256ad36cab82cb79b71d7d58a8c2417 –password pass.txt

To create a new account with parity

 parity account new –chain ropsten –keys-path /root/.local/share/io.parity.ethereum/keys

Important Points
1) Make sure you have unlocked the address of owner ethereum to deploy smart contract (You need to use –unlock params in Geth or Parity)

2) Install the headless chromedriver (https://sites.google.com/a/chromium.org/chromedriver/downloads)  or yum install -f chromedriver chromium xorg-x11-server-Xvfb

Thanks for reading it. Hope this covers the important installation instruction while you stuck in the TokenmarketICO installation.

IBM Blockchain Technology

IBM Blockchain Technology

Now-a-days Business networks are inefficient because all participants in the business network maintain a ledger of all transactions that take place in the business. This process seems to be inefficient due to its cost. This process is expensive because of duplication of effort and intermediaries adding costs for their services.

One solution to this problem is blockchain, which provides a shared ledger technology that allows any participant in the network to see the one system of record, or ledger. By using blockchain technology, businesses can benefit from a more efficient transfer of goods and services.

The following videos in the next module describe business networks and transactions, the problems that blockchain can solve, what blockchain is and how it works, and key use cases.

Shared ledger

A Shared ledger is a type of database that is shared, replicated, and synchronized among the members of a network. There is no central administrator or centralised data storage. All participants within a network can have their own identical copy of the ledger. Any changes to the ledger are reflected in all copies.Every record in the Shared ledger has a timestamp and unique cryptographic signature, thus making the ledger an auditable history of all transactions in the network.

With all transactions being added to a single public ledger, it reduces the clutter and complications of multiple ledgers.

Smart Contract

Smart contracts are self-executing contracts with the terms of the agreement between buyer and seller being directly written into lines of code. The code and the agreements contained therein exist across a distributed, decentralized blockchain network. Smart contracts help you exchange money, property, shares, or anything of value in a transparent, conflict-free way while avoiding the services of a middleman.

Because the rules are so secure and easy to follow, even simple devices like phones or locks can be programmed to obey what everyone has agreed to. And the way of doing this is strong enough that attackers or malfunctioning computers can’t break the rules that have been set up. As long as it’s built right, not even the person who makes the app will have the power to break the rules they agreed to.


Privacy is of utmost importance at the Blockchain group of companies. Blockchain, and its encryption features allow high degrees of security and privacy.

Privacy in blockchain can be explained in 3 terms.

Privacy: Appropriate confidentiality between subsets of participants are secured and User identity not linked to a transaction by way of transaction history on the Blockchain

Fungibility: Every coin is worth the same value and is thus mutually interchangeable. No coin risks potential blacklisting nor debasement due to deprecating transaction history.

Decentralization: All nodes have equal power and control; there are no nodes that have more influence than others, i.e. masternodes. The currency is not created, maintained nor represented by any one person or company, i.e. a central authority

Privacy on Blockchain is one of the major features that attracts users towards the technology.Despite its decentralized nature and the ability for anyone to view every transaction or data transfer on Blockchain, encrypted communication prevents third party interference with messages sent across the technology.


Trust is the key element of blockchain technology. When transactions are executed and settled on a distributed ledger, counterparties don’t need to have an established trust relationship. If each participant in the transaction trusts the blockchain itself then they don’t need to directly trust each other.

In Blockchain community, each member maintains his own copy of the information, and all members can validate any updates collectively. The information could represent transactions, contracts, assets, identities, or practically anything else that can be described in digital form.

Entries are permanent, transparent, and search-able, which makes it possible for community members to view transaction histories. Each update is a new “block” added to the end of the “chain.” A protocol manages how new edits or entries are initiated, validated, recorded and distributed.

Crucially, privacy can also be selectively enforced, allowing varying degrees of anonymity or protection of sensitive information beyond those who have explicitly been given access. With blockchain, cryptology replaces third-party intermediaries as the keeper of trust.

How do you make money from investing in stocks?

What is a stock exchange?

A stock market is where investors meet to buy and sell shares. Stocks allow you to own a share of a public corporation. The stock price is based on the corporation’s earnings.

A stock market is similar to a share market. The key difference is that a stock market helps you trade financial instruments like bonds, mutual funds, derivatives as well as shares of companies. A share market only allows trading of shares.

Role of a stock exchange

The main function of a stock exchange is to facilitate the transactions associated with both buying and selling of securities. Stock exchanges have multiple roles :

Raising capital for businesses

  • Profit sharing
  • Facilitating company growth
  • Creating investment opportunities for small investors
How to buy shares?

In order to buy shares, the first step is to open a trading account or Demat (dematerialized) account so that you will get Unique User Id and Password through which you can Buy/Sell Shares.These accounts are linked to the account holder’s bank savings accounts to ensure smooth transfer of funds.

Once you open an account you will tell your broker how many and what types of stocks you’d like to purchase. The broker executes the trade on the your behalf. In turn, he or she earns a commission, normally several cents per share. Online trading sites typically charge lower commission fees, because most of the trading is done electronically.


For Stock advice visit : http://www.moneycontrol.com/markets/stock-advice/

How does a stock exchange operate?

Open an account:   Open an trading and D- Mat account with them. To open an account You need to submit your documents like PAN , Adhar and bank statement. And get ready with both trading and D-mat account.

Select stock broker:  The first and foremost step is selecting the stock broker, as you cannot trade in stock market without broker. It is advisable to chose discount broker because their brokerage will be less.

With the help of stockbrokers, the buyers and sellers participating in a stock market carry out their transactions. The brokers representing selling parties take their orders to the stock exchange floor and then find brokers representing parties willing to invest in similar stocks. If both parties agree to trade at the fixed price, the transaction takes place.

Requirements to trade in a stock exchange :

Minimum age : 21 years
Education : At least HSC or equivalent qualification

Benefits and drawbacks of listing your company on a stock exchange

Benefits :

  1. Creates a market valuation for the business and enables the opportunity to raise capital for expansion.
  2. Provides access to an acquisition currency and transparency around the value of the business.
  3. Encourages employee commitment by rewarding them with something of clear value.
  4. Creates a heightened public profile and improves the ability to attract high calibre board members.
  5. Improves supplier, investor and customer confidence and improves your standing in the marketplace.

Drawbacks :

  1. Going public is an expensive, time-consuming process. Going public is the process of selling ownership of a part of your company to strangers
  2. Once your corporation goes public, management becomes more complicated. You can no longer make decisions autonomously.
  3. A public corporation, however, must make extensive quarterly and annual disclosures about business operations, financial condition and other internal matters.
  4. Taking your company public increases the potential liability of the company and its officers and directors for mismanagement.



Which stock to buy today? :  https://economictimes.indiatimes.com/markets/stocks/recos

Evolution of blockchain technology in bigger companies.

Economic experts projects the blockchain market could be valued at $400 million by 2019. For that reason, some of the biggest companies in banking industry and technology have entered into the space to evaluate how this technology could change the financial world.


IBM and Linux, for instance, have brought together some of the brightest minds in the industry and technology to work on blockchain technology through the Hyperledger Project.

The Hyperledger Project is under the umbrella of the Linux Foundation and seeks to incorporate findings by blockchain projects such as Blockstream, Ripple, Digital Asset Holdings and others in order to make blockchain technology useful for the world’s biggest corporations. IBM has also contributed its own code to the project. Currently, IBM employees were working on crypto-security and distributed systems.

For more details on IBM-Blockchain visit : https://developer.ibm.com/blockchain/

Microsoft :

Microsoft Corporation started their blockchain journey in November 2015. Microsoft actively identifies existing technology gaps with blockchain and helps organizations build durable enterprise-grade applications.

In May, Azure introduced a new blockchain framework to reduce the time and cost associated with blockchain Proof of Concept (PoC) projects. Microsoft identified that a significant amount of time (8-12 weeks) and cost (as much as $300,000) was involved in developing a blockchain PoC, and this was resulting in huge missed opportunity, and thus Microsoft has been working to overcome such challenges.

In another step to bringing blockchain to the enterprise, Microsoft unveiled the Coco Framework in August 2017. Coco Framework reduces the complexities involved in the development techniques while offering high-transaction speed (more than 1600 transactions per second), distributed governance and confidentiality—much needed ingredients for successful commercial adoption of blockchain.

Microsoft and Mojix collaborated to enable blockchain-powered smart contracts to create swifter supply chains that can lower overall business costs, foster closer cooperation and enhance trust among retailers, suppliers, and logistic partners. This was followed by its alliance with Tierion for a service that generates, manages, and validates attestations.

Read more about Microsoft Azure here : https://azure.microsoft.com/en-in/solutions/blockchain/

Samsung :

Seoul plans to first apply blockchain in municipal duties that actively collect private information of citizens. Samsung SDS has announced a lucrative agreement with the Korean government to create a new Blockchain technology-based platform for welfare, public safety and transportation by 2022. The hope is to increase transparency for the government services.

In May, it joined global blockchain alliance EEA, whose members include Microsoft and Intel, to spread blockchain use globally.Last month it applied its blockchain solution to local shipping firms for trials.

Samsung is now pushing for its security solution offerings, such as Nexledger and its biometric solution Nexsign. Last month, it announced the integration of behavioral biometrics into Nexsign through a partnership with BioCatch.

Read more about Samsung SDS here :https://www.samsungsds.com/global/en/solutions/bns/blockchain/Blockchain.html

Introduction to Apache Hadoop

What is Hadoop?

Apache Hadoop is an open-source software which was born out of a need to process an avalanche (sudden arrival or occurrence of something in overwhelming quantities) of big data.

The web was generating more and more information on a daily basis, and it was becoming very difficult to index over one billion pages of content. Hadoop is for storage and large scale processing of data.

Basically, it’s a way of storing enormous data sets across distributed clusters of servers and then running “distributed” analysis applications in each cluster.

Logo :

Founders :

Hadoop was created by Doug Cutting and Mike Cafarella in 2005.Named after his son’s yellow color toy elephant named as Hadoop.


Normal DB – store data, retrieve data using SQL Query

Hadoop – stores data, retrieve data but no queries involved

Two main parts – a distributed file system for data storage and a data processing framework.

Distributed file-system  – HDFS

Data processing framework – MapReduce


HDFS writes data once to the server and then reads and reuses it many times.

Namenode – master
Datanode – slaves

Input data was splitted into blocks (equal size 128kbs) and stored in Datanode. Name node determines the mapping of blocks to the DataNodes.

MapReduce :

MapReduce is the heart of Hadoop. It is this programming paradigm that allows for massive scalability across hundreds or thousands of servers in a Hadoop cluster.

Map – which takes a set of input data and converts it into another set of data tuples (Key & values),

Reduce – takes the output from a map as input and combines those data and produce the final output.

MAP – Job tracker – that splits the job submitted by the client into small sub-tasks. (do job scheduling & task tracker monitoring)

Reduce – Task tracker – that actually do the tasks in parallel in a distributed manner on data stored in datanodes.

Instead of MapReduce, we can use querying tools like Pig Hadoop and Hive Hadoop that gives the data hunters strong power and flexibility.

Example for MapReduce :  Find maximum temperature of each City

YARN : Used in Hadoop V2. (Advanced of MapReduce)

Apache Yarn – “Yet Another Resource Negotiator” is the resource management layer of Hadoop V2.

Yarn allows different data processing engines like graph processing, interactive processing, stream processing as well as batch processing to run and process data stored in HDFS simultaneously with Mapreduce.

YARN Architecture :

Resource Manager – (Master of YARN) (Similar to Job tracker)

RM manages the global assignments of resources (CPU and memory) among all the applications. It arbitrates system resources between competing applications.

  • Scheduler

The scheduler is responsible for allocating the resources to the running application.

  • Application manager

It manages running Application in the cluster, i.e., it is responsible for starting application masters and for monitoring and restarting them on different nodes in case of failures.

Node Manager – (Slave of YARN)  (Similar to Task tracker)

NM is responsible for containers, monitoring their resource usage and reporting the same to the Resource Manager. Manage the user process on that machine.

Application Master

One application master runs per application. It negotiates resources from the resource manager and works with the node manager. It manages the resource needs of an application.

Advantages of Hadoop :

1. Resilient to failure – In HDFS data was stored on every machine in the cluster. If any machine slows down data can be retrieved from another.

2. Speedy Output – Output can be fetched in a fraction of a second.

3.  Cost effective – Bigdata can be stored and processed in a very effective cost.

4.  Scalable – Data can be fetched from hundreds or thousands of servers.

Limitations of Hadoop :

1.  Missing encryption – Data can be read by everyone.

2. Code are in Java –  Java has been heavily exploited by cybercriminals.

3. Lacks the ability to efficiently support small files.

Companies currently using Hadoop :

  • Facebook
  • Twitter
  • Amazon
  • Ebay
  • Apple
  • AOL
  • Yahoo

Mysql InnoDB Cluster Setup On CentOS 7 X64

Installing Mysql 5.7 in CentOS 7 X64 bit operating system

Get the yum repository from here as per your OS config.
Run the below command
yum localinstall mysql57-community-release-el7-11.noarch.rpm

Grep the mysql 5.7 releases from our OS Repo

yum repolist enabled | grep “mysql.*-community.*”

yum install mysql-community-server

After Installation, Restart the mysql 5.7 server and grep the temporary password from mysql log files.

service mysqld restart

grep “password” /var/log/mysqld.log

Login into Mysql 5.7 server using temporary password and change the root password as per your wish.

mysql -uroot -p

ALTER USER ‘root’@’localhost’ IDENTIFIED BY ‘<Password@123>’;

Mysql InnoDB Cluster Setup On CentOS 7 X64

Part 1 – InnoDB Cluster – Configuring Mysql 5.7

We have to enforce group replication configurations in the server. It is one of the mandatory pre-validation to initiate clustering setup.

Open /etc/my.cnf and paste the following lines


gtid_mode = ON


So far you have finished the Mysql configuration requirement to start Cluster set up.

Installing Mysql shell and Mysql router

You need to install the following in all the instances you wish to connect with InnoDB cluster.

yum install mysql-shell

yum install mysql-router

To access the Mysql Admin Shell. Type the following

mysqlsh –log-level=DEBUG3

mysql-js> dba.verbose=2

The above options will help us to see extended log or error messages while configuring Cluster.

Let’s say you want to connect 3 Mysql server in 3 different machine. You need to configure local instance in all the machines.

Execute the following in all machines.

mysql-js> dba.configureLocalInsance()

mysql-js> dba.checkInstanceConfiguration(‘<user1>@<hostname>:3306’)

The above command will display the message something like this.

You are right, it will show error.

Now, restart the mysql server after you did the above steps in all the machines check the instance configuration and move the clustering process.


Deploying Cluster

From the primary node. Create the Innodb cluster and add our instances into it

var cluster=dba.createCluster(‘mycluster’,{ipWhitelist:”,,″});

If you receive “The group replication applier thread was killed’” in mysqld.log messages

You can run the following query in mysql root

SET GLOBAL group_replication_ip_whitelist = ‘,,’;

Note: Check the SELinux status, Firewalld and Iptables. Make sure it does not affect your mysql connection between nodes. Using the whitelist method you should not get any errors.




You will get Status:OK output. Awesome!



If the output is START GROUP REPLICATION error you should whitelist the instance ip address in all the 3 servers.

Check the cluster status.

mysql-js> cluster.status()


“clusterName”: “mycluster”,
“defaultReplicaSet”: {

“name”: “default”,
“primary”: “”,
“status”: “OK”,
“statusText”: “Cluster is ONLINE and can tolerate up to ONE failure.”,
“topology”: {

“”: {

“address”: “”,
“mode”: “R/W”,
“readReplicas”: {},
“role”: “HA”,
“status”: “ONLINE”

“”: {

“address”: “”,
“mode”: “R/O”,
“readReplicas”: {},
“role”: “HA”,
“status”: “ONLINE”

“”: {
“address”: “”,
“mode”: “R/O”,
“readReplicas”: {},
“role”: “HA”,
“status”: “ONLINE”

Good work, You have created a InnoDB cluster network with 3 instances into it.

“statusText”: “Cluster is ONLINE and can tolerate up to ONE failure.”

The above line states that If a server is offline the other 2 servers can manage and serve the data to the client or customers.



MetaMask is an Ethereum extension for your browser. It connects you to Ethereum applications (called dApps) easily and securely. MetaMask is also a digital wallet: you can store digital currencies in it and use it.

How to use MetaMask

1. Go to https://metamask.io/ and click on GET CHROME PLUGIN. Click on the ‘+ADD TO CHROME’ button to add the plugin to chrome.


2. The MetaMask plugin is displayed at the right top of your Chrome browser.

3. Then Scroll down and click Continue to agree with MetaMask terms of use.

4. It will ask to set a password. Fill in a strong password and click Create. Do NOT lose your password!

5. Safe your secret 12 word recovery key somewhere safe and click on “I’VE COPIED IT SOMEWHERE SAFE” to continue.

How to Buy Ether with Bitcoin in Metamask

1. Click BUY to buy Ether with Bitcoin or any other Altcoin

2. Now choose ShapeShift

3. Type BTC for Bitcoin, fill in your Bitcoin Refund address and click Submit.

4. Scan the QRcode or send Bitcoin to the displayed address to start the conversion. Note that the amount you can send can be limited.

Notes :

    • Don’t forget to unlock Metamask before using and lock it back immediately after using it (i.e. while still staying on the website where you used it). It will keep your data secure.
    • If you want to use MetaMask on a computer other than the one you installed it at, you’ll need the seed phrase to restore it. Also don’t forget about the password, you will need it to unlock the extension when you’re ready to use it.
    • If you want to install MetaMask extension on a new computer, use “Import existing DEN” button in create password step and follow the instructions.
    • MetaMask requires the permission to read and write to any webpage which is potentially risky.
    • As is always the case with Ethereum transactions, you will need some small amount of ether available in your MetaMask wallet to sign the transactions.
    • Better try with a small amount first and double check everything.

For more details : https://www.youtube.com/watch?v=2YeyTF5lalE