"DevOps: What, Why, and How?"

What is DevOps?

DevOps is a set of practices, tools, and cultural philosophies that aim to improve the ability to deliver applications at a high velocity. Its goal is to automate and streamline the process of software delivery, with a strong focus on continuous integration, testing, monitoring, and quality assurance. By reducing the reliance on manual processes, DevOps reduces the delivery time of software from development to production.

Why DevOps?

Before DevOps

Imagine a developer working on building an application. The end goal is for the customer to use the application. Without DevOps, the process would be quite different. Here's how the traditional setup used to work:

1. Step 1: The developer writes the code.
2. Step 2: The code is then sent to the system administrator to deploy it onto a server.
3. Step 3: The testing team manually tests the application to check for bugs.
4. Step 4: The build and release team take the code through multiple environments such as staging, pre-production, and production.

This process is:

• Time-consuming
• Cumbersome
• Error-prone

And, of course, it results in lengthy delivery cycles and lots of manual tasks. With no central collaboration, it often leads to blame games, inefficiencies, and difficulty in identifying where things went wrong.

With DevOps

Now, let’s bring in DevOps. DevOps helps to automate this entire process by integrating tools that streamline the workflow. Developers, testers, and operations teams collaborate more closely using DevOps practices. This results in faster and more reliable application delivery, with continuous feedback to improve code quality.

Here’s what the DevOps approach looks like:

• Developers write code and commit it to a centralized repository (e.g., GitHub).
• The code is automatically built using Continuous Integration (CI) tools like Jenkins or CircleCI.
• Automated tests are run to ensure quality.
• The code is automatically deployed to staging and production environments using Continuous Delivery (CD) tools like Kubernetes or Docker.

The Need for DevOps

DevOps reduces manual steps and increases the overall efficiency of software delivery. It eliminates bottlenecks, reduces human error, and promotes collaboration across the development, operations, and testing teams. Some key benefits of DevOps are:

• Faster delivery times: Automation speeds up the delivery pipeline.
• Better collaboration: Developers and operations teams work together to solve problems.
• Improved quality: Automated testing and continuous integration lead to fewer bugs and more reliable software.
• Continuous monitoring: Issues can be identified in real-time, allowing for immediate resolution.

Software Development Lifecycle (SDLC)

In traditional software development, the Software Development Lifecycle (SDLC) follows a series of steps:

1. Planning
2. Defining
3. Designing
4. Building
5. Testing
6. Deploying

DevOps focuses on improving the Building, Testing, and Deploying phases by automating them. Here’s a breakdown:

1. Code Storage: Developers write code and store it in a version control system (e.g., GitHub, GitLab) that is easily accessible by the team.

2. Automated Testing: Once the code is written, it is automatically tested using CI tools. For example, every time a developer pushes code to the repository, a CI tool like Jenkins runs automated tests to validate the changes.

3. Deployment: Once the code is validated, it’s automatically deployed to staging and production environments. Tools like Docker and Kubernetes make it easy to deploy applications with minimal downtime.

This automated process makes the software development lifecycle faster, more efficient, and less prone to errors.

Virtual Machines (VMs)

A key concept in DevOps is Virtual Machines (VMs). VMs provide a virtualized environment to run applications, which can be easily scaled up or down based on demand. Let’s explore the differences between physical servers and virtual machines.

Physical Server vs Virtual Machine

• Physical Server: A dedicated machine where the operating system runs directly on the hardware. For example, a traditional web server or a database server.

• Virtual Machine: A software-emulated environment running on top of physical hardware. Multiple VMs can run on the same physical machine, each having its own operating system and resources.

Example:

• EC2 in AWS is an example of a virtual machine that allows you to run applications in the cloud. By provisioning an EC2 instance, you can quickly deploy an app without the need to buy and manage physical servers.

Why Virtual Machines Are Important in DevOps

Virtual machines allow you to quickly scale infrastructure up or down, which is crucial in DevOps. With VM automation, you can:

• Provision infrastructure on demand based on requirements.
• Isolate environments for different stages of development (e.g., staging, production).
• Reuse infrastructure configurations across different environments.

Tools for automating infrastructure creation include:

• Terraform: Allows you to define infrastructure as code (IaC) and manage it through version-controlled configuration files.
• Ansible: A configuration management tool that automates the deployment and management of infrastructure.
• CloudFormation (AWS): AWS-native service for automating infrastructure provisioning.

How to Create an EC2 Instance

Creating an EC2 instance in AWS can be done with a few simple steps:

1. Log in to the AWS Console and go to the EC2 Dashboard.
2. Click on Launch Instance to start creating a new virtual machine.
3. Choose an AMI (Amazon Machine Image): This is the operating system image for your VM. You can choose from Linux, Windows, etc.
4. Select an Instance Type: Choose the size of the virtual machine based on your needs (e.g., t2.micro for light workloads).
5. Configure the Instance: Choose settings like networking, IAM roles, security groups, etc.
6. Review and Launch: Review your settings and click Launch.

Example: Here's how you can access an EC2 instance via SSH (for Linux instances):

How to Access EC2 Instances

There are two main ways to access an EC2 instance:

1. Command-Line Interface (CLI): You can use SSH (for Linux) or RDP (for Windows) to access the instance from the command line. This is ideal for running scripts and performing command-line tasks.

• SSH (Linux): ssh -i "key.pem" ec2-user@your-instance-public-ip
• RDP (Windows): Remote Desktop Protocol (RDP) is used to access Windows instances.

1. Graphical User Interface (GUI): For instances running a graphical user interface (GUI), you can access them through a remote desktop connection (RDP for Windows or VNC for Linux).

Linux vs Windows for DevOps

When it comes to DevOps, Linux is often preferred over Windows for several reasons:

1. Flexibility: Linux provides more flexibility and control over the system, which is critical for automation.
2. Open Source: Linux is open-source, meaning you can customize it to fit your needs, and it’s more cost-effective than Windows.
3. Command Line Efficiency: The Linux command line (Bash) is highly efficient for scripting and automating tasks, which is essential in DevOps.
4. Performance: Linux generally performs better under load, making it the ideal environment for running multiple applications and services simultaneously.

Fundamentals of Operating Systems

Understanding the fundamentals of operating systems (OS) is crucial in DevOps. An OS manages hardware resources and provides services for software applications. Key components of an OS include:

• Kernel: The core part of the OS that manages communication between hardware and software.
• Processes: Individual tasks running on the OS.
• Memory Management: How memory is allocated and managed for processes.

Shell Scripting in DevOps

Shell scripting is a fundamental skill for DevOps engineers. Shell scripts are used to automate repetitive tasks, such as provisioning servers, deploying applications, or running tests.

In Linux, Bash scripting is commonly used. Here’s an example of a basic shell script that automates the process of updating a system:

bash
#!/bin/bash
# Update system
sudo apt update && sudo apt upgrade -y
echo "System updated successfully!"