5 Pros and Cons of Distributed Systems Architecture

5 Pros and Cons of Distributed Systems Architecture | Distributed Systems Explained | Distributed Computing

A distributed system is comprised of multiple components located across different machines that may or may not be part of a network. These machines converse with one another to synchronize and order any actions requested by the user. These actions are carried out in such a way as to appear to the user like they have been performed by a single, coherent system.

Microservices can also be an example of a distributed system. They run multiple copies of each component on separate machines – adding redundancies to the various layers so the failure of a single machine doesn’t end up with a loss of data or function.

Each component communicates with each other over a linked network, and not within a single mainframe process. The key takeaway here is that distributed systems are a collection of autonomous computing elements that come together to act as a whole, coherent system. Bear in mind that the machines that contain each component do not have to be in the same physical location, either.

SUBSCRIBE to Kofi Group:https://www.youtube.com/channel/UC1mBXiJnLtiDHMtpga0Ugaw?view_as=subscriber


00:00 - Intro to distributed systems architecture
01:08 - What is a non-distributed system
02:50 - What is a distributed system
04:39 - Distributed systems pros
06:39 - Distributed systems cons
07:19 - The current trend with distributed systems architecture
*

Website: https://www.kofi-group.com/

Blog article version: https://www.kofi-group.com/distributed-systems-explained-in-10-minutes/

Remote jobs (including distributed systems jobs): https://www.kofi-group.com/search-jobs/

Kofi Group helps startups outcompete FAANG (Facebook, Amazon, Apple, Netflix, Google) and big tech in the highly competitive, war for talent.

Our videos cover hiring tips and strategies for startups, software engineering and machine learning interview preparation, salary negotiation best practices, compensation analysis, computer science basics, artificial intelligence, tips for other recruiters, and much more!

Hit the SUBSCRIBE button and we’ll see you in the comments!

––––––––––––––––––––––––––––––
Skydive by Loxbeats https://soundcloud.com/loxbeats​
Creative Commons — Attribution 3.0 Unported — CC BY 3.0
Free Download / Stream: http://bit.ly/2uUKEmd​
Music promoted by Audio Library https://youtu.be/hpAp6GMSM30​
––––––––––––––––––––––––––––––

#kofigroup #distributedsystems #microservices #softwarearchitecture

#microservices #distributed systems architecture

What is GEEK

Buddha Community

5 Pros and Cons of Distributed Systems Architecture

5 Pros and Cons of Distributed Systems Architecture

5 Pros and Cons of Distributed Systems Architecture | Distributed Systems Explained | Distributed Computing

A distributed system is comprised of multiple components located across different machines that may or may not be part of a network. These machines converse with one another to synchronize and order any actions requested by the user. These actions are carried out in such a way as to appear to the user like they have been performed by a single, coherent system.

Microservices can also be an example of a distributed system. They run multiple copies of each component on separate machines – adding redundancies to the various layers so the failure of a single machine doesn’t end up with a loss of data or function.

Each component communicates with each other over a linked network, and not within a single mainframe process. The key takeaway here is that distributed systems are a collection of autonomous computing elements that come together to act as a whole, coherent system. Bear in mind that the machines that contain each component do not have to be in the same physical location, either.

SUBSCRIBE to Kofi Group:https://www.youtube.com/channel/UC1mBXiJnLtiDHMtpga0Ugaw?view_as=subscriber


00:00 - Intro to distributed systems architecture
01:08 - What is a non-distributed system
02:50 - What is a distributed system
04:39 - Distributed systems pros
06:39 - Distributed systems cons
07:19 - The current trend with distributed systems architecture
*

Website: https://www.kofi-group.com/

Blog article version: https://www.kofi-group.com/distributed-systems-explained-in-10-minutes/

Remote jobs (including distributed systems jobs): https://www.kofi-group.com/search-jobs/

Kofi Group helps startups outcompete FAANG (Facebook, Amazon, Apple, Netflix, Google) and big tech in the highly competitive, war for talent.

Our videos cover hiring tips and strategies for startups, software engineering and machine learning interview preparation, salary negotiation best practices, compensation analysis, computer science basics, artificial intelligence, tips for other recruiters, and much more!

Hit the SUBSCRIBE button and we’ll see you in the comments!

––––––––––––––––––––––––––––––
Skydive by Loxbeats https://soundcloud.com/loxbeats​
Creative Commons — Attribution 3.0 Unported — CC BY 3.0
Free Download / Stream: http://bit.ly/2uUKEmd​
Music promoted by Audio Library https://youtu.be/hpAp6GMSM30​
––––––––––––––––––––––––––––––

#kofigroup #distributedsystems #microservices #softwarearchitecture

#microservices #distributed systems architecture

Ruth  Nabimanya

Ruth Nabimanya

1620633584

System Databases in SQL Server

Introduction

In SSMS, we many of may noticed System Databases under the Database Folder. But how many of us knows its purpose?. In this article lets discuss about the System Databases in SQL Server.

System Database

Fig. 1 System Databases

There are five system databases, these databases are created while installing SQL Server.

  • Master
  • Model
  • MSDB
  • Tempdb
  • Resource
Master
  • This database contains all the System level Information in SQL Server. The Information in form of Meta data.
  • Because of this master database, we are able to access the SQL Server (On premise SQL Server)
Model
  • This database is used as a template for new databases.
  • Whenever a new database is created, initially a copy of model database is what created as new database.
MSDB
  • This database is where a service called SQL Server Agent stores its data.
  • SQL server Agent is in charge of automation, which includes entities such as jobs, schedules, and alerts.
TempDB
  • The Tempdb is where SQL Server stores temporary data such as work tables, sort space, row versioning information and etc.
  • User can create their own version of temporary tables and those are stored in Tempdb.
  • But this database is destroyed and recreated every time when we restart the instance of SQL Server.
Resource
  • The resource database is a hidden, read only database that holds the definitions of all system objects.
  • When we query system object in a database, they appear to reside in the sys schema of the local database, but in actually their definitions reside in the resource db.

#sql server #master system database #model system database #msdb system database #sql server system databases #ssms #system database #system databases in sql server #tempdb system database

Einar  Hintz

Einar Hintz

1594631472

Pros and Cons of Ionic Development

Entrepreneurs around the world want a top-notch mobile application for their business in both Android and iOS platforms. Most of them get stuck mid-way where they struggle to pick the best technology suitable for their business. From questions such as native mobile development or cross-platform development? Flutter or Ionic or React Native?. Each technology and development approach has its own Pros and Cons from which you will need to choose the right one for your business. If you think Ionic is the right cross-platform application development, here are a few pros and cons of Ionic development. 

What is Ionic Framework?

Being an open-source SDK for building Hybrid mobile applications in both Android and iOS platforms, Ionic is the best choice for building top of the line mobile applications. This Ionic framework is completely based on Apache Cordova and Angular. More precisely, Ionic is an npm module that requires the installation of Node JS to function.

One can build a full functioning mobile application in both platforms using their Javascript, HTML, and CSS knowledge without requiring the basics of Kotlin or Java. More than 5 Million mobile applications are built using this Ionic framework by leveraging its platform-specific UI elements, innumerable libraries, and more exciting features.

The applications that are built using the Ionic framework are cross-platform, web-based, and have access to native device’s APIs.

Ionic Applications are

  • Cross-platform – Single code base for both platforms (except native components)
  • Web-based – Built using web-views and can be displayed in a browser like PWAs.
  • Access to native API components – They can access native device’s camera, files, and others.

Advantages of Ionic Development

Quick Development and Time To Market

For entrepreneurs and business owners, ionic development can be beneficial if they want to develop a mobile application in both platforms in a short period of time while comparing to native applications. Building native applications specifically for each platform can be time-consuming which can imply a delay in time to market and development cost of native applications are generally expensive.

#mobile app development #ionic 4 advantages #ionic 4 best practices #ionic 5 #ionic appflow #ionic capacitor pros and cons #ionic vs react native #react native pros and cons #what is ionic app development

Lindsey  Koepp

Lindsey Koepp

1597689240

Resilience in Deep Systems

When using microservices architecture to build a successful product, a product that needs to rapidly grow, sooner or later, you realize that your system becomes “deep.”

The depth of a system can be considered as the number of microservices layers in the application stack.

Today’s forefront cloud technologies, such as Service Mesh, Containers, and Serverless computing, enable teams to easily add many microservices layers to their system.

RELATED SPONSORED CONTENT
Kubernetes Up & Running – Download the eBook (By O’Reilly)
Database Requirements for Microservices
Knative Cookbook (By O’Reilly): Building Effective Serverless Applications with Kubernetes and OpenShift – Download Now
The Business Bottleneck – Download the eBook (By O’Reilly)
From Docker to Kubernetes: Container Networking 101 (By O’Reilly)
RELATED SPONSOR

**NGINX Plus is the complete application delivery platform for the modern web. **Start your 30 day free trial.

A microservice within such a system is not actually independent - it relies on other microservices and vice versa.

When microservices communication grows deep, it complicates the company’s ability to quickly diagnose errors or performance bottlenecks.

Therefore, deep systems are a serious challenge for R&D teams who want to sustain resilience, fault-tolerance, and performance.

Without the right mindset and the right tooling, the product and it’s customers will be jeopardized.

It’s possible to build complex systems, with deep chains of microservices, without compromising on resilience.

Here are 3 ingredients that can help you nourish resilience in deep systems.

1. Service granularity

Don’t go with the hype; correspond to a real business capability.

When designing complex applications using microservice architecture, we’re looking to define a set of cohesive and loosely-coupled services. One of the biggest questions in that regard is, how will we break down our application into microservices?

Because microservices architecture essentially follows the Unix philosophy of “Do one thing and do it well,” you could simply say that each atomic function should be a microservice (i.e. the hype). While in theory it sounds perfect, simply following that philosophy can create an enormous amount of microservices. Are you going to be successful in maintaining that many services effectively?

I’m going to provision the “integer” service in us-west-1

Said once a hyped developer

In reality, we found that defining microservices that correspond to a real business capability will result in a sane amount of self-contained pieces of business functionality. Those pieces can still be very cohesive, loosely coupled, scale well, be testable, built, and owned by a small enough team. All of which are the pillars of microservices.

Moreover, it’s a common practice to avoid code duplications in multiple microservices by creating a shared library, i.e. DRY (Don’t Repeat Yourself). DRY is an important concept. Yet, sometimes too hyped. In reality, we found that sometimes shared libraries couple our microservices to each other, reducing the effectiveness of the isolation and independence between the microservices. It also slows down teams from making changes, since they are not always fully aware of the usage patterns of other teams. In fact, balancing microservices granularity goes hand in hand with balancing the right amount of shared libraries. Both shared libraries and code duplication are a burden in hyper-granular microservices architecture. But when keeping a balanced microservice granularity, the price of code duplication can pay off as increased independence.

#distributed tracing #distributed systems #microservices #complex systems #architecture & design #development #article

ERIC  MACUS

ERIC MACUS

1647540000

Substrate Knowledge Map For Hackathon Participants

Substrate Knowledge Map for Hackathon Participants

The Substrate Knowledge Map provides information that you—as a Substrate hackathon participant—need to know to develop a non-trivial application for your hackathon submission.

The map covers 6 main sections:

  1. Introduction
  2. Basics
  3. Preliminaries
  4. Runtime Development
  5. Polkadot JS API
  6. Smart Contracts

Each section contains basic information on each topic, with links to additional documentation for you to dig deeper. Within each section, you'll find a mix of quizzes and labs to test your knowledge as your progress through the map. The goal of the labs and quizzes is to help you consolidate what you've learned and put it to practice with some hands-on activities.

Introduction

One question we often get is why learn the Substrate framework when we can write smart contracts to build decentralized applications?

The short answer is that using the Substrate framework and writing smart contracts are two different approaches.

Smart contract development

Traditional smart contract platforms allow users to publish additional logic on top of some core blockchain logic. Since smart contract logic can be published by anyone, including malicious actors and inexperienced developers, there are a number of intentional safeguards and restrictions built around these public smart contract platforms. For example:

Fees: Smart contract developers must ensure that contract users are charged for the computation and storage they impose on the computers running their contract. With fees, block creators are protected from abuse of the network.

Sandboxed: A contract is not able to modify core blockchain storage or storage items of other contracts directly. Its power is limited to only modifying its own state, and the ability to make outside calls to other contracts or runtime functions.

Reversion: Contracts can be prone to undesirable situations that lead to logical errors when wanting to revert or upgrade them. Developers need to learn additional patterns such as splitting their contract's logic and data to ensure seamless upgrades.

These safeguards and restrictions make running smart contracts slower and more costly. However, it's important to consider the different developer audiences for contract development versus Substrate runtime development.

Building decentralized applications with smart contracts allows your community to extend and develop on top of your runtime logic without worrying about proposals, runtime upgrades, and so on. You can also use smart contracts as a testing ground for future runtime changes, but done in an isolated way that protects your network from any errors the changes might introduce.

In summary, smart contract development:

  • Is inherently safer to the network.
  • Provides economic incentives and transaction fee mechanisms that can't be directly controlled by the smart contract author.
  • Provides computational overhead to support graceful logical failures.
  • Has a low barrier to entry for developers and enables a faster pace of community interaction.

Substrate runtime development

Unlike traditional smart contract development, Substrate runtime development offers none of the network protections or safeguards. Instead, as a runtime developer, you have total control over how the blockchain behaves. However, this level of control also means that there is a higher barrier to entry.

Substrate is a framework for building blockchains, which almost makes comparing it to smart contract development like comparing apples and oranges. With the Substrate framework, developers can build smart contracts but that is only a fraction of using Substrate to its full potential.

With Substrate, you have full control over the underlying logic that your network's nodes will run. You also have full access for modifying and controlling each and every storage item across your runtime modules. As you progress through this map, you'll discover concepts and techniques that will help you to unlock the potential of the Substrate framework, giving you the freedom to build the blockchain that best suits the needs of your application.

You'll also discover how you can upgrade the Substrate runtime with a single transaction instead of having to organize a community hard-fork. Upgradeability is one of the primary design features of the Substrate framework.

In summary, runtime development:

  • Provides low level access to your entire blockchain.
  • Removes the overhead of built-in safety for performance.
  • Has a higher barrier of entry for developers.
  • Provides flexibility to customize full-stack application logic.

To learn more about using smart contracts within Substrate, refer to the Smart Contract - Overview page as well as the Polkadot Builders Guide.

Navigating the documentation

If you need any community support, please join the following channels based on the area where you need help:

Alternatively, also look for support on Stackoverflow where questions are tagged with "substrate" or on the Parity Subport repo.

Use the following links to explore the sites and resources available on each:

Substrate Developer Hub has the most comprehensive all-round coverage about Substrate, from a "big picture" explanation of architecture to specific technical concepts. The site also provides tutorials to guide you as your learn the Substrate framework and the API reference documentation. You should check this site first if you want to look up information about Substrate runtime development. The site consists of:

Knowledge Base: Explaining the foundational concepts of building blockchain runtimes using Substrate.

Tutorials: Hand-on tutorials for developers to follow. The first SIX tutorials show the fundamentals in Substrate and are recommended for every Substrate learner to go through.

How-to Guides: These resources are like the O'Reilly cookbook series written in a task-oriented way for readers to get the job done. Some examples of the topics overed include:

  • Setting up proper weight functions for extrinsic calls.
  • Using off-chain workers to fetch HTTP requests.
  • Writing tests for your pallets It can also be read from

API docs: Substrate API reference documentation.

Substrate Node Template provides a light weight, minimal Substrate blockchain node that you can set up as a local development environment.

Substrate Front-end template provides a front-end interface built with React using Polkadot-JS API to connect to any Substrate node. Developers are encouraged to start new Substrate projects based on these templates.

If you face any technical difficulties and need support, feel free to join the Substrate Technical matrix channel and ask your questions there.

Additional resources

Polkadot Wiki documents the specific behavior and mechanisms of the Polkadot network. The Polkadot network allows multiple blockchains to connect and pass messages to each other. On the wiki, you can learn about how Polkadot—built using Substrate—is customized to support inter-blockchain message passing.

Polkadot JS API doc: documents how to use the Polkadot-JS API. This JavaScript-based API allows developers to build custom front-ends for their blockchains and applications. Polkadot JS API provides a way to connect to Substrate-based blockchains to query runtime metadata and send transactions.

Quiz #1

👉 Submit your answers to Quiz #1

Basics

Set up your local development environment

Here you will set up your local machine to install the Rust compiler—ensuring that you have both stable and nightly versions installed. Both stable and nightly versions are required because currently a Substrate runtime is compiled to a native binary using the stable Rust compiler, then compiled to a WebAssembly (WASM) binary, which only the nightly Rust compiler can do.

Also refer to:

Lab #1

👉 Complete Lab #1: Run a Substrate node

Interact with a Substrate network using Polkadot-JS apps

Polkadot JS Apps is the canonical front-end to interact with any Substrate-based chain.

You can configure whichever endpoint you want it to connected to, even to your localhost running node. Refer to the following two diagrams.

  1. Click on the top left side showing your currently connected network:

assets/01-polkadot-app-endpoint.png

  1. Scroll to the bottom of the menu, open DEVELOPMENT, and choose either Local Node or Custom to specify your own endpoint.

assets/02-polkadot-app-select-endpoint.png

Quiz #2

👉 Complete Quiz #2

Lab #2

👉 Complete Lab #2: Using Polkadot-JS Apps

Notes: If you are connecting Apps to a custom chain (or your locally-running node), you may need to specify your chain's custom data types in JSON under Settings > Developer.

Polkadot-JS Apps only receives a series of bytes from the blockchain. It is up to the developer to tell it how to decode and interpret these custom data type. To learn more on this, refer to:

You will also need to create an account. To do so, follow these steps on account generation. You'll learn that you can also use the Polkadot-JS Browser Plugin (a Metamask-like browser extension to manage your Substrate accounts) and it will automatically be imported into Polkadot-JS Apps.

Notes: When you run a Substrate chain in development mode (with the --dev flag), well-known accounts (Alice, Bob, Charlie, etc.) are always created for you.

Lab #3

👉 Complete Lab #3: Create an Account

Preliminaries

You need to know some Rust programming concepts and have a good understanding on how blockchain technology works in order to make the most of developing with Substrate. The following resources will help you brush up in these areas.

Rust

You will need familiarize yourself with Rust to understand how Substrate is built and how to make the most of its capabilities.

If you are new to Rust, or need a brush up on your Rust knowledge, please refer to The Rust Book. You could still continue learning about Substrate without knowing Rust, but we recommend you come back to this section whenever in doubt about what any of the Rust syntax you're looking at means. Here are the parts of the Rust book we recommend you familiarize yourself with:

  • ch 1 - 10: These chapters cover the foundational knowledge of programming in Rust
  • ch 13: On iterators and closures
  • ch 18 - 19: On advanced traits and advanced types. Learn a bit about macros as well. You will not necessarily be writing your own macros, but you'll be using a lot of Substrate and FRAME's built-in macros to write your blockchain runtime.

How blockchains work

Given that you'll be writing a blockchain runtime, you need to know what a blockchain is, and how it works. The **Web3 Blockchain Fundamental MOOC Youtube video series provides a good basis for understanding key blockchain concepts and how blockchains work.

The lectures we recommend you watch are: lectures 1 - 7 and lecture 10. That's 8 lectures, or about 4 hours of video.

Quiz #3

👉 Complete Quiz #3

Substrate runtime development

High level architecture

To know more about the high level architecture of Substrate, please go through the Knowledge Base articles on Getting Started: Overview and Getting Started: Architecture.

In this document, we assume you will develop a Substrate runtime with FRAME (v2). This is what a Substrate node consists of.

assets/03-substrate-architecture.png

Each node has many components that manage things like the transaction queue, communicating over a P2P network, reaching consensus on the state of the blockchain, and the chain's actual runtime logic (aka the blockchain runtime). Each aspect of the node is interesting in its own right, and the runtime is particularly interesting because it contains the business logic (aka "state transition function") that codifies the chain's functionality. The runtime contains a collection of pallets that are configured to work together.

On the node level, Substrate leverages libp2p for the p2p networking layer and puts the transaction pool, consensus mechanism, and underlying data storage (a key-value database) on the node level. These components all work "under the hood", and in this knowledge map we won't cover them in detail except for mentioning their existence.

Quiz #4

👉 Complete Quiz #4

Runtime development topics

In our Developer Hub, we have a thorough coverage on various subjects you need to know to develop with Substrate. So here we just list out the key topics and reference back to Developer Hub. Please go through the following key concepts and the directed resources to know the fundamentals of runtime development.

Key Concept: Runtime, this is where the blockchain state transition function (the blockchain application-specific logic) is defined. It is about composing multiple pallets (can be understood as Rust modules) together in the runtime and hooking them up together.

Runtime Development: Execution, this article describes how a block is produced, and how transactions are selected and executed to reach the next "stage" in the blockchain.

Runtime Develpment: Pallets, this article describes what the basic structure of a Substrate pallet is consists of.

Runtime Development: FRAME, this article gives a high level overview of the system pallets Substrate already implements to help you quickly develop as a runtime engineer. Have a quick skim so you have a basic idea of the different pallets Substrate is made of.

Lab #4

👉 Complete Lab #4: Adding a Pallet into a Runtime

Runtime Development: Storage, this article describes how data is stored on-chain and how you could access them.

Runtime Development: Events & Errors, this page describe how external parties know what has happened in the blockchain, via the emitted events and errors when executing transactions.

Notes: All of the above concepts we leverage on the #[pallet::*] macro to define them in the code. If you are interested to learn more about what other types of pallet macros exist go to the FRAME macro API documentation and this doc on some frequently used Substrate macros.

Lab #5

👉 Complete Lab #5: Building a Proof-of-Existence dApp

Lab #6

👉 Complete Lab #6: Building a Substrate Kitties dApp

Quiz #5

👉 Complete Quiz #5

Polkadot JS API

Polkadot JS API is the javascript API for Substrate. By using it you can build a javascript front end or utility and interact with any Substrate-based blockchain.

The Substrate Front-end Template is an example of using Polkadot JS API in a React front-end.

  • Runtime Development: Metadata, this article describes the API allowing external parties to query what API is open for the chain. Polkadot JS API makes use of a chain's metadata to know what queries and functions are available from a chain to call.

Lab #7

👉 Complete Lab #7: Using Polkadot-JS API

Quiz #6

👉 Complete Quiz #6: Using Polkadot-JS API

Smart contracts

Learn about the difference between smart contract development vs Substrate runtime development, and when to use each here.

In Substrate, you can program smart contracts using ink!.

Quiz #7

👉 Complete Quiz #7: Using ink!

What we do not cover

A lot 😄

On-chain runtime upgrades. We have a tutorial on On-chain (forkless) Runtime Upgrade. This tutorial introduces how to perform and schedule a runtime upgrade as an on-chain transaction.

About transaction weight and fee, and benchmarking your runtime to determine the proper transaction cost.

Off-chain Features

There are certain limits to on-chain logic. For instance, computation cannot be too intensive that it affects the block output time, and computation must be deterministic. This means that computation that relies on external data fetching cannot be done on-chain. In Substrate, developers can run these types of computation off-chain and have the result sent back on-chain via extrinsics.

Tightly- and Loosely-coupled pallets, calling one pallet's functions from another pallet via trait specification.

Blockchain Consensus Mechansim, and a guide on customizing it to proof-of-work here.

Parachains: one key feature of Substrate is the capability of becoming a parachain for relay chains like Polkadot. You can develop your own application-specific logic in your chain and rely on the validator community of the relay chain to secure your network, instead of building another validator community yourself. Learn more with the following resources:

Terms clarification

  • Substrate: the blockchain development framework built for writing highly customized, domain-specific blockchains.
  • Polkadot: Polkadot is the relay chain blockchain, built with Substrate.
  • Kusama: Kusama is Polkadot's canary network, used to launch features before these features are launched on Polkadot. You could view it as a beta-network with real economic value where the state of the blockchain is never reset.
  • Web 3.0: is the decentralized internet ecosystem that, instead of apps being centrally stored in a few servers and managed by a sovereign party, it is an open, trustless, and permissionless network when apps are not controlled by a centralized entity.
  • Web3 Foundation: A foundation setup to support the development of decentralized web software protocols. Learn more about what they do on thier website.

Others


Author: substrate-developer-hub
Source Code: https://github.com/substrate-developer-hub/hackathon-knowledge-map
License: 

#blockchain #substrate