AWS Linux EC2 instances are commonly used in projects for several reasons:

Cost-Effective: AWS Linux EC2 instances are often more cost-effective compared to Windows-based instances due to the absence of licensing fees for the operating system.
Performance: AWS Linux is optimized for running on AWS infrastructure, providing efficient resource utilization and better performance.
Security: AWS regularly updates and maintains their Linux AMIs, ensuring that security patches and updates are readily available. Additionally, the Linux community actively contributes to security enhancements.
Community Support: Linux enjoys a large and active community, which means extensive online resources, forums, and documentation are available to troubleshoot issues and seek solutions.
Compatibility: Linux is compatible with a wide range of open-source software, tools, and frameworks, making it a preferred choice for projects built on open-source technologies.
Flexibility: Linux offers a high degree of customization and flexibility, enabling developers to tailor the OS to their specific project requirements.
Containerization: Linux is the dominant choice for containerization platforms like Docker and Kubernetes, making it ideal for projects adopting modern cloud-native architectures.
Performance-Centric Applications: For high-performance computing tasks and data analysis, Linux offers advantages in terms of resource utilization and processing power.
DevOps and Automation: Linux is widely used in DevOps workflows and automation due to its command-line capabilities, shell scripting, and ease of integration with automation tools.
Cloud-Native Development: As cloud-native technologies gain popularity, Linux is a natural fit due to its compatibility with containerization and microservices architectures.
Serverless Applications: For serverless applications built using AWS Lambda or other serverless computing technologies, Linux-based environments are commonly used due to their lightweight nature.
Scalability: Linux's lightweight nature makes it well-suited for scaling applications in cloud environments, enabling efficient use of resources.
Web Hosting: Deploy web servers like Apache, Nginx, or lighttpd on AWS Linux EC2 instances to host websites and web applications.
Application Hosting: Run various applications, such as Node.js, Python, Ruby on Rails, or PHP-based applications, on AWS Linux EC2 instances to serve dynamic content and applications.
Content Management Systems (CMS): Install and manage popular CMS platforms like WordPress, Drupal, or Joomla on AWS Linux EC2 instances for building and managing websites.
Development Environments: Utilize AWS Linux EC2 instances as development environments, allowing developers to build, test, and debug applications before deploying to production.
Continuous Integration and Continuous Deployment (CI/CD): Set up CI/CD pipelines using tools like Jenkins, GitLab CI/CD, or Travis CI on AWS Linux EC2 instances to automate software delivery.
Docker Hosting: Deploy and manage Docker containers on AWS Linux EC2 instances to containerize applications and improve scalability and portability.
Database Hosting: Host databases like MySQL, PostgreSQL, MongoDB, or Redis on AWS Linux EC2 instances to store and manage application data.
Monitoring and Logging: Deploy monitoring and logging solutions like Prometheus, Grafana, ELK stack (Elasticsearch, Logstash, Kibana), or CloudWatch agent on AWS Linux EC2 instances to monitor and analyze system and application logs.
Version Control Repositories: Set up Git repositories using tools like GitLab, GitHub, or Bitbucket on AWS Linux EC2 instances for version control and collaborative software development.
Data Analytics and Data Science: Deploy data analysis tools like Jupyter Notebooks, RStudio, or Python libraries for data science tasks on AWS Linux EC2 instances.
Security Appliances: Use AWS Linux EC2 instances to deploy security appliances like intrusion detection systems (IDS) or web application firewalls (WAF) to enhance the security of your infrastructure.
Proxy Servers and VPN: Deploy proxy servers (Squid) or VPN servers (OpenVPN) on AWS Linux EC2 instances to control outgoing web traffic or provide secure remote access.
Testing and Staging Environments: Use AWS Linux EC2 instances to set up testing and staging environments that mirror the production environment for software testing and development.
Cloud-Native Applications: Develop and deploy cloud-native applications using AWS Linux EC2 instances, taking advantage of cloud-native tools and technologies.
Container Orchestration: Use AWS Linux EC2 instances as nodes in container orchestration platforms like Kubernetes to manage and scale containerized applications.

These use cases showcase the versatility of AWS Linux EC2 instances and demonstrate how they can cater to various projects with different requirements and technologies.

Overall, AWS Linux EC2 instances are chosen in projects for their performance, cost-effectiveness, and compatibility with a wide range of modern technologies. It's important to consider the specific needs and requirements of a project when choosing the operating system for EC2 instances, and in many cases, AWS Linux provides a compelling choice for various workloads and applications.