Day 8 - Basic Git & GitHub for DevOps Engineers

When "Why" is clear, then "How" is easy.

In this blog, we'll look at the "why" part of using version control. The "how" will be discussed later.

Why Git?

Consider a scenario where multiple people want to work remotely on a project. This can be conveniently achieved if the project is hosted on a central repository or a shared cloud-space or some sort of reliable protocol. Let's say tasks are delegated to a team as follows :

The need of VCS

It is not necessary that to attain their respective features, they are not going to touch each other's files or some common file. There might arise a situation when P1 has made changes in file1 and P2 is also making changes to file1 at the same time. So, the changes may go un-synchronized or un-recognized by either of them. It can also lead to several other problems in the development process as we'll see as we proceed with the Version Control discussion in the near future.

Looking at the above scenario, it is pretty obvious that in real-life software development and maintenance process there may be multiple developers working parallely on the same project - sometimes perhaps making changes to the same file. This is one major reason where version-control comes to the rescue - i.e. to track changes in the code. Thus there arose a need for a reliable Version Control System(VCS) for overall code management.

The current undisputed solution

A popular hacker of great trust, Mr. Linus Torvalds invented GIT, a Free and Open Source Software (FOSS) in the year 2005; the same man who gave us the Linux kernel that drives almost all the servers that keep the internet and the digital world running today.
Click👇 the image below to listen to The TED talk of The Big Brain...

What is Version Control System(VCS)?

Types of VCS (common ones):

1. Centralized VCS (CVCS)

   • This is the type of VCS where there is one central repository, to which all the users are connected to.

   • This central repository can be a developer's machine or a dedicated server.

   • This type is generally used by those teams where a single user uses a fixed physical machine and less likely to move away from it. e.g Subversion(SVN), Concurrent Version Systems(CVS)

2. Decentralized/Distributed VCS (DVCS)

   • This type of VCS allows physically users working with multiple computers to work collaboratively with other developers remotely.

   • Here, each user fully mirrors or owns a snapshot of the remote repository locally on their machine.

   • So, if in case the server becomes unavailable, any client repository can send its version to any other client needing it or back to the server. e.g. Git

What is Git?

Git is a decentralized, Free and Open Source Software(FOSS) version-control system or a DVCS.

• It is commonly used for collaborative working among software developers.

• It is used for version tracking and reverting back-and-forth among various "versions" as per the requirement.

• It can be conveniently used to resolve merge conflicts.
  A short video on FOSS

What is GitHub/GitLab?

GitHub/GitLab is a web-based platform that hosts version control system using Git.

• GitLab is a pure FOSS tool i.e. it is openly available for a user to run locally, study the program, redistrubute the code, make changes to its source code and redistribute to the public who can practice the same freedom.

• GitHub on the other hand is a subsidiary of Microsoft and is a closed-source platform. However, it is a very popular platform among developers due to its large infrastructure and funding.

Creating a github repository

To install and setup git on your linux machine, checkout the following docs:

https://git-scm.com/book/en/v2/Getting-Started-Installing-Git

OR

sudo apt update; sudo apt install git

git version # if it shows a version, successfully installed!
# setup your git and SSH locally. 
# Follow the next steps to create a repository

1. Navigate to https://github.com

2. As shown in the image below, click on the "+" sign to get a drop down menu. Click on "New repository".

   

3. You will be redirected to a page shown below.

   • Enter the repository name of your choice.

   • Add a description if you want.

   • If you want to keep the repository visible to everyone, select Public, else Private.

   • Here since I am creating this repository for demo, I have kept it private.

     

4. Click on Create repository in the bottom right.

5. You will be redirected to a page like this.

   • 

6. In the above image, the numbers marked 1, 2 and 3 in red are for different use-cases.

   • Here, I have assumed you have not created a Git repository before

     

7. First option is :

   …or create a new repository on the command line

• Enter in your terminal the lines given in the field corresponding to number "1".

• 

• Now hit refresh in the browser. You will be able to see the remote repository.

• 

• Other option is:

  ...or push an existing repository from the command line

• Do this if you have an existing git repo locally that you want to maintain a remote respository too.

    git remote add origin git@github.com:akshaykhoje/DemoRepo.git
    git branch -M main
    git push -u origin main
  

Thus, your repository is created.

Happy Learning ;)