INDUSTRY PRACTICES AND TOOLS

INDUSTRY PRACTICES AND TOOLS

VERSION CONTROLLING

Software systems grow larger and more complex it is difficult to handle a whole project. So it is very important to manage the source of different stages. So version control systems are a category of software tools that help a software team to manage changes to source code over time.

VCS keeps every modifications, in special kind of databases. So if you have a mistake, then the developer can turn back and get the earlier one. There are three types of version controlling systems.

01.  Local version control systems.

02.  Centralized version control systems.

03.  Distributed version control systems.

A component of software configuration management, version control, also known as revision control or source control is the management of changes to documents, computer programs, large web sites, and other collections of information.

The need for a logical way to organize and control revisions has existed for almost as long as writing has existed, but revision control became much more important, and complicated when the era of computing began. The numbering of book editions and of specification revisions are examples that date back to the print-only era. Today, the most capable (as well as complex) revision control systems are those used in software development, where a team of people may concurrently make changes to the same files.

Version control systems (VCS) most commonly run as stand-alone applications, but revision control is also embedded in various types of software such as word processors and spreadsheets.

LOCAL VERSION CONTROL SYSTEMS

This one is the oldest version of VCS. In this VCS everything in the computer. So the big issue is it cannot be used for collaborative development.

This tool basically works by keeping patch sets (that is, the difference between the file's content at progressive stages) using a special format in the version tracker that is stored in your local hard disk.

It can then recreate the file's contents exactly at any given point in time by adding up all the relevant patches in order and "checking it out" (reproducing the content to the user's workplace).

CENTRALIZED VERSION CONTROL SYSTEMS

Local version control system cannot be used for collaborative software development. But centralized version can be used for all collaborative purposes. Everyone know their each works and most obvious is the single point of failure the centralized server represents.

People were not able to work collaboratively on the same project, as the files with their versions are stored in somebody's local computer and were not accessible to other people working on the same files.

DISTRIBUTED VERSION CONTROL SYSTEMS

The best VCS. Because no single point of failure can be occurred. Simply said that all client is a server machine. Clients don’t just check out the latest snapshot of the files. If one server destroyed others can be copied back. System can collaborate with different groups of people in different ways.

Whenever you bet big time on one single unit, the probability of losing is also high. Yes, there is a high degree of risk involved in using a centralized version control system because the users only have the last version of files in their system for working purposes; there is a chance you might ultimately lose the entire history of your files if the server gets corrupt and if you don't have fail-safe procedures implemented.

Now people get confused. You risk everything when you store your entire history in one single place using a centralized version control concept; on the contrary you lose the power to work collaboratively when you use local version control.

GIT

GIT is the most commonly used version control system today because it has so many good features such as speed, data integrity and etc. This one belongs to distributed version control system.

This is a free and open source distributed version control system designed to handle everything from small to very large projects with the speed and efficiency. GIT is easy to learn and has a tiny footprint with lightning fast performance. 

There are popular implementations of GIT such as GIThub, GitLab, GitBucket, CloudForge and etc. 

GIT TERMINOLOGY

BRANCH - A branch represents an independent line of development. Branches serve as an abstraction for the edit/stage/commit process discussed in Git Basics, the first module of this series. You can think of them as a way to request a brand new working directory, staging area, and project history. New commits are recorded in the history for the current branch, which results in a fork in the history of the project.

HEAD - Git’s way of referring to the current snapshot. Internally, the git checkout command simply updates the HEAD to point to either the specified branch or commit. When it points to a branch, Git doesn't complain, but when you check out a commit, it switches into a “detached HEAD” state.

HOOK - A script that runs automatically every time a particular event occurs in a Git repository. Hooks let you customize Git’s internal behavior and trigger customizable actions at key points in the development life cycle.

MASTER - The default development branch. Whenever you create a git repository, a branch named "master" is created, and becomes the active branch.

FULL REQUEST - Pull requests are a feature that makes it easier for developers to collaborate using Bit bucket. They provide a user-friendly web interface for discussing proposed changes before integrating them into the official project.

REPOSITORY - A collection of commits, and branches and tags to identify commits.

WORKING TREE - The tree of actual checked out files, normally containing the contents of the HEAD commit's tree and any local changes you've made but haven't yet committed.

CLONE – This is an exact copy of existing repository.

TAG - A reference typically used to mark a particular point in the commit chain. In contrast to a head, a tag is not updated by the commit command.

GIT WORKFLOW - The Git flow Workflow streamlines the release cycle by using isolated branches for feature development, release preparation, and maintenance. Its strict branching model also lends some much needed structure to larger projects.

CONTENT DELIVERY/DISTRIBUTION NETWORK [CDN]

A content delivery/distribution network (CDN) is a system of distributed servers (network) that deliver pages and other web content to a user, based on the geographic locations of the user, the origin of the web page and the content delivery server.

This service is effective in speeding the delivery of content of websites with high traffic and websites that have global reach. The closer the CDN server is to the user geographically, the faster the content will be delivered to the user. CDNs also provide protection from large surges in traffic.

HOW CDNs WORK

Servers nearest to the website visitor respond to the request. The content delivery network copies the pages of a website to a network of servers that are dispersed at geographically different locations, caching the contents of the page. When a user requests a web page that is part of a content delivery network, the CDN will redirect the request from the originating site's server to a server in the CDN that is closest to the user and deliver the cached content. CDNs will also communicate with the originating server to deliver any content that has not been previously cached.

The process of bouncing through CDNs is nearly transparent to the user. The only way a user would know if a CDN has been accessed is if the delivered URL is different than the URL that has been requested.

BENEFITS OF USING A CDN

·         significantly reduced page load time of your website

·         increased revenue by 1% for every 100 Ms of improvement to your page load time

·         retaining more customers (they are more satisfied)

·         more manageable traffic

·         maximum availability of your product

·         more secure network

·         no geographical barriers

·         easy delivery of video, audio rich content

·         build more interactive website at no cost of losing visitors due to latencies

·         reaching mobile customers with ease

·         branching out to new markets, regions

·         easy management of traffic peaks

·         more scalability to your business, you can grow it as much as you want to

·         less or now down times

·         setting your own criteria to enable the best possible performance for your website

VIRTUALIZATION

There are some gaps between development and implementation environment. Because sometimes it can be different platforms, missing dependencies, frameworks and also wrong configurations. So in that case this issue can be overcome by develop software/project in a virtual environment.

The main goal of virtualization is to manage workloads by radically transforming traditional computing to make it more scalable. Virtualization has been a part of the IT landscape for decades now, and today it can be applied to a wide range of system layers, including operating system-level virtualization, hardware-level virtualization and server virtualization.

There are five types of virtualization.

01.  Application virtualization

02.  Desktop virtualization

03.  Hardware virtualization

04.  Network virtualization

05.  Storage virtualization

Application virtualization - This is a process where applications are virtualized and delivered from a server to the end user’s device, such as laptops, smartphones, and tablets. So instead of logging into their computers at work, users will be able to gain access to the application right from their device, provided an Internet connection is available. This is particularly popular for businesses that require the use of their applications on the go.

Desktop virtualization - Similar to application virtualization mentioned above, desktop virtualization separates the desktop environment from the physical device and configured as a “virtual desktop infrastructure” (VDI). One of the biggest advantages of desktop virtualization is that users are able to access all their personal files and applications on any PC, meaning they can work from anywhere without the need to bring their work computer. It also lowers the cost of software licensing and updates. Maintenance and patch management are simple, since all of the virtual desktops are hosted at the same location.

Hardware virtualization - Perhaps the most common type of virtualization today, hardware virtualization is made possible by a virtual machine manager (VM) called the “hypervisor”. The hypervisor creates virtual versions of computers and operating systems and consolidates them into one large physical server, so that all the hardware resources can be utilized more efficiently. It also enables users to run different operating systems on the same machine simultaneously.

Network virtualization - Network virtualization combines all physical networking equipment into a single, software-based resource. It also divides available bandwidth into multiple, independent channels, each of which can be assigned to servers and devices in real time. Businesses that would benefit from network virtualization are ones that have a large number of users and need to keep their systems up and running at all times. With the distributed channels, your network speed will increase dramatically, allowing you to deliver services and applications faster than ever before.

Storage virtualization - This type of virtualization is very easy and cost-effective to implement, since it involves compiling your physical hard drives into a single cluster. Storage virtualization is handy when it comes to planning for disaster recovery, since the data stored on your virtual storage can be replicated and transferred to another location. By consolidating your storage into a centralized system, you can eliminate the hassles and costs of managing multiple storage devices.

System Requirements for Virtualization

Review the following requirements for the Virtual Server Protection (VSP) package.

General Package Requirements

The computer on which you plan to install the package must satisfy the following system requirements:

Operating Systems	·         Microsoft Windows Server 2016 x64 Editions ·         Microsoft Windows Server 2012 R2 x64 Editions ·         Microsoft Windows Server 2012 x64 Editions ·         Microsoft Windows Server 2008 x64 Editions
Hard Drive	500 GB recommended. Depending upon the number of virtual machines that you are planning to backup, ensure that the backup server computer has sufficient free space to store all virtual machine data.
Memory	16 GB RAM minimum required
Processor	All Windows-compatible processors supported
IIS	IIS must be enabled on the backup server.

Supported Web Browsers for the Command Center

You can run the Command Center on the following browsers:

·         Apple Safari version 8.0 and later

·         Google Chrome v40 and later

·         Microsoft Edge

·         Microsoft Internet Explorer (IE) v10 or later

·         Mozilla Firefox v47.0 or later

Database Engine

Microsoft SQL Server 2014 Express edition is automatically installed during the installation of the package.

The maximum database size for Microsoft SQL Server 2014 Express edition is 10 gigabytes. If your Express edition database approaches the 10 gigabyte limit, a critical event will appear in the dashboard. To increase the size of the database, you can upgrade to Microsoft SQL Server 2014 Standard edition.

PROS AND CONS OF VIRTUALIZATION

PROS –

·         Capital expenditure savings. Virtualization lets companies reduce their IT costs by requiring fewer hardware servers and related resources to achieve the same level of computing performance, availability and scalability.

·         Operational expenditure savings. Once servers are virtualized, your IT staff can greatly reduce the ongoing administration and management of manual, time-consuming processes by automating operations, thus resulting in lower operational expenses.

·         Data centre and energy-efficiency savings. As companies reduce the size of their hardware and server footprint, they lower their energy consumption, cooling power and data centre square footage, thus resulting in lower costs.

CONS –

·             The upfront costs are heavy

·             Efficient resource utilization

·             Not all hardware or software can be virtualized

HYPERVISOR

A hypervisor or virtual machine monitor (VMM) is computer software, firmware or hardware that creates and runs virtual machines. A computer on which a hypervisor runs one or more virtual machines is called a host machine, and each virtual machine is called a guest machine.

Type-1 native or bare-metal hypervisors

These hypervisors run directly on the host's hardware to control the hardware and to manage guest operating systems. For this reason, they are sometimes called bare mental hypervisors. The first hypervisors, which IBM developed in the 1960s, were native hypervisors.

Type-2 or hosted hypervisors

These hypervisors run on a conventional operating system (OS) just as other computer programs do. A guest operating system runs as a process on the host. Type-2 hypervisors abstract guest operating systems from the host operating system. 

DIFFERENT BETWEEN VM AND EMULATOR

Virtual machines make use of CPU self-virtualization, to whatever extent it exists, to provide a virtualized interface to the real hardware. Emulators emulate hardware without relying on the CPU being able to run code directly and redirect some operations to a hypervisor controlling the virtual container.

 VMs VS CONTAINERS

VMs - A virtual machine (VM) is an emulation of a computer system. Put simply, it makes it possible to run what appear to be many separate computers on hardware that is actually one computer.

The operating systems (“OS”) and their applications share hardware resources from a single host server, or from a pool of host servers. Each VM requires its own underlying OS, and the hardware is virtualized. A hypervisor, or a virtual machine monitor, is software, firmware, or hardware that creates and runs VMs. It sits between the hardware and the virtual machine and is necessary to virtualize the server.

Since the advent of affordable virtualization technology and cloud computing services, IT departments large and small have embraced virtual machines (VMs) as a way to lower costs and increase efficiencies.

BENEFITS OF VMs

• All OS resources available to apps
• Established management tools
• Established security tools
• Better known security controls

CONTAINERS - With containers, instead of virtualizing the underlying computer like a virtual machine (VM), just the OS is virtualized.

Containers sit on top of a physical server and its host OS — typically Linux or Windows. Each container shares the host OS kernel and, usually, the binaries and libraries, too. Shared components are read-only. Sharing OS resources such as libraries significantly reduces the need to reproduce the operating system code, and means that a server can run multiple workloads with a single operating system installation. Containers are thus exceptionally light — they are only megabytes in size and take just seconds to start. Compared to containers, VMs take minutes to run and are an order of magnitude larger than an equivalent container.

In contrast to VMs, all that a container requires is enough of an operating system, supporting programs and libraries, and system resources to run a specific program. What this means in practice is you can put two to three times as many as applications on a single server with containers than you can with a VM. In addition, with containers you can create a portable, consistent operating environment for development, testing, and deployment.

BENEFITS OF CONTAINERS

• Reduced IT management resources
• Reduced size of snapshots
• Quicker spinning up apps
• Reduced & simplified security updates
• Less code to transfer, migrate, upload workloads