Programming Infrastructure Questions and Answers for AWS Interview

Introduction

Creating your infrastructure in AWS by programming is essential for a smooth and effective management process. AWS CloudFormation templates offer a structured way to consistently describe and set up resources. Automating your infrastructure enables the generation of separate systems for each code change, making integration testing thorough and reliable. 

This programming approach ensures your AWS resources are managed with reliability, scalability, and agility; following AWS interview questions and answers on Programming Infrastructure can help you understand AWS in depth, helping you better prepare for your interview.

Q1: How Can You Control AWS Infrastructure, and What Tools or Methods Are Available for Interacting With It?

Ans. AWS offers a user-friendly way to manage its infrastructure through an Application Programming Interface (API). This control is accessible using Software Development Kits (SDKs) for various programming languages, command line interfaces, and other sophisticated tools. Interacting with AWS involves calling the REST API using the HTTPS protocol. 

Practically every AWS action, whether starting a server with a single API call, creating 1 TB of storage, or initiating a Hadoop cluster, can be seamlessly achieved through the API.

Q2: What Does the Concept of “Infrastructure as Code” Entail, and How Can It Enhance the Quality of It Systems?

Ans. "Infrastructure as Code" involves utilizing a high-level programming language to control IT systems. Similar to how software development benefits from automated tests, code repositories, and build servers, applying these techniques to infrastructure code enhances its quality. 

You can improve quality by treating infrastructure as code by implementing automated tests, code repositories, and building servers. It's essential not to confuse "Infrastructure as Code" with "Infrastructure as a Service" (IaaS), which refers to renting servers, storage, and network resources with a pay-per-use pricing model.

Q3: How Does the AWS Command-Line Interface (Cli) Simplify Interaction With AWS, and What Are the Key Features of the CLI?

Ans. The AWS Command-Line Interface (CLI) offers a convenient means to interact with AWS directly from the command line, functioning seamlessly on Linux, Mac, and Windows systems. Developed in Python, the CLI provides a unified interface for all AWS services, ensuring consistent and efficient management. By default, the CLI outputs results in JSON format, enhancing readability and compatibility. The next step involves installing and configuring the CLI, enabling users to engage with AWS services effectively through command-line operations.

Q4: How Does Automation in Infrastructure Enable the Creation of Isolated Systems for Code Changes, and Why Is This Beneficial for Integration Testing?

Ans. With automated infrastructure, each code change introduced to the repository triggers the creation of a new system encompassing servers, databases, networks, etc. This approach facilitates running integration tests in isolation from other concurrent changes. 

By spawning a new system for each code modification, it ensures a clean and independent environment to assess the change's impact. This isolation enhances the reliability and effectiveness of integration testing, allowing for thorough evaluations without interference from other simultaneous code alterations in the repository.

Q5: What Is DevOps, and How Does Automation Contribute to Its Goal of Delivering High-Quality Software Efficiently?

Ans. DevOps, driven by software development, seeks to bring development and operations closer, ensuring rapid software delivery without compromising quality. Effective communication and collaboration are crucial. Automation plays a pivotal role in achieving multiple daily deployments. When you commit code, it's automatically built and tested. 

Upon passing tests, it's deployed to the testing environment and moves to production if integration tests succeed. Continuous monitoring and real-time log analysis ensure the success of the implemented change. This seamless process aims to deliver software efficiently while maintaining a high-quality standard.

Q6: What Is the Distinction Between a Cloudformation Template and a Stack, and How Can This Analogy Be Likened to Class Versus Object in Programming?

Ans. In CloudFormation, a stack is called a stack when you create infrastructure from a template. Drawing an analogy to programming, the relationship between a template and a stack is akin to that of a class and an object. 

The template serves as a blueprint, existing only once, while multiple stacks can be generated from the same template. This distinction emphasizes the reusable nature of templates, much like classes, and the instantiated, deployable instances represented by stacks, resembling objects in programming.

Q7: Why Should Scripting Be Preferred Over the Graphical AWS Management Console, and What Advantages Does It Offer?

Ans. Scripting, unlike the AWS Management Console, provides several advantages. Firstly, scripts are reusable, saving considerable time in the long run. They enable the swift construction of new architectures by incorporating ready-to-use modules from past projects. 

Automating infrastructure creation streamlines deployment pipelines and ensures accuracy – a script serves as precise and understandable documentation. Scripts prove invaluable in scenarios like reproducing tasks from the previous week or facilitating a colleague covering your responsibilities, making them a valuable asset in any workflow.

Q8: What Is the Purpose of a Template in AWS Cloudformation, and How Does It Differ From an Action-Oriented Approach?

Ans. A template in AWS CloudFormation describes your infrastructure in JSON format, allowing CloudFormation to interpret it. This approach, known as descriptive, involves expressing how your infrastructure should look and be connected rather than listing specific actions. 

Unlike an action-oriented approach, you don't instruct CloudFormation on the actions needed or the sequence in which they should be executed. Instead, the descriptive approach focuses on conveying the desired state of the infrastructure, providing a more abstract and comprehensive perspective for CloudFormation to follow.

Q9: Why Is It Crucial to Specify the Awstemplateformatversion in a Cloudformation Template, and What Are the Potential Issues if Not Specified?

Ans. It is essential to always specify the AWSTemplateFormatVersion in a CloudFormation template, with the currently valid value being "2010-09-09". 

Failing to do so results in CloudFormation assuming the latest version by default, which could lead to complications if a new format version is introduced. Specifying the version explicitly ensures template compatibility and prevents potential issues arising from unintentional assumptions about the latest format version.

Q10: What Are the Benefits of Using AWS Software Development Kits (Sdks) for Making Calls to the AWS API, and Which Programming Languages Are Supported by AWS Sdks?

Ans, AWS SDKs offer a convenient way to interact with the API across multiple programming languages. The SDKs handle critical functionalities such as authentication, error retry mechanisms, HTTPS communication, and JSON (de)serialization. 

AWS provides SDK support for various programming languages, including Android, iOS, Java, .NET, Python, Ruby, Go, PHP, and JavaScript for Node.js runtime and browsers. While users can choose the SDK compatible with their preferred language, the examples in this book specifically utilize JavaScript within the Node.js runtime environment.

Q11: What Are the Advantages of Using AWS Cloudformation, and How Does It Address Common Challenges in Infrastructure Management?

Ans, The benefits of AWS CloudFormation include:

• Consistency: CloudFormation provides a consistent way to describe infrastructure on AWS, eliminating variations that may arise when using scripts. This clarity is especially beneficial for new developers and operators.
• Dependency Handling: CloudFormation can manage dependencies effectively, preventing issues like setting up a web server before its load balancer is available. This helps avoid dependency challenges in complex infrastructure setups.
• Replicability: CloudFormation enables the creation of identical infrastructures, ensuring that test environments mirror production environments promoting consistency.
• Customizability: Custom parameters can be incorporated into CloudFormation, allowing templates to be tailored to specific requirements.
• Testability: Infrastructure becomes testable as CloudFormation allows the creation of a template, facilitating testing and subsequent shutdown after completion.
• Updatability: CloudFormation supports infrastructure updates, identifying changes in the template and seamlessly applying them to the existing infrastructure.

Q12: What Are the Critical Components of a Basic AWS Cloudformation Template, and How Is It Structured?

Ans. A fundamental AWS CloudFormation template consists of five essential parts:

• Format Version: Ensure you specify the latest template format version, currently 2010-09-09, to prevent issues with potential future format updates.
• Description: Clearly define the purpose or subject of the template to provide context.
• Parameters: Customize the template using parameters, allowing users to input values like domain name, customer ID, or database password.
• Resources: Describe the smallest building blocks, such as virtual servers, load balancers, or elastic IP addresses.
• Outputs: Similar to parameters but in reverse, outputs provide information from the template, such as the public name of an EC2 server. This structure forms the foundation of a CloudFormation template.

Q13: How Can the AWS CLI Be Installed on Windows Using the Msi Installer, and What Are the Necessary Steps?

Ans. Installing the AWS CLI on Windows involves the following steps:

• Download the AWS CLI MSI installer (32-bit or 64-bit) from http://aws.amazon.com/cli/.
• Run the downloaded installer and follow the installation wizard for CLI installation.
• You can Open PowerShell as an administrator by searching for It in the Start menu and choosing "Run as Administrator."
• In PowerShell, enter "Set-ExecutionPolicy Unrestricted," and press Enter to allow the execution of unsigned PowerShell scripts.
• Close the PowerShell window; no need to work as an administrator.
• Open PowerShell via the Start menu entry.
• Verify the installation by executing "aws --version" in PowerShell. This ensures the AWS CLI is functioning correctly.

Q14: What Are the Critical Properties of Cloudformation Parameters, and How Are They Used?

Ans. CloudFormation parameter properties include:

Default: Sets a default value for the parameter.

Example: Default: "default_value"

NoEcho: Hides the parameter value in graphical tools, handy for passwords.

Example: "NoEcho": true

AllowedValues: Specifies possible values for the parameter as an array.

Example: "AllowedValues": ["1", "2", "3"]

AllowedPattern: Uses a regular expression to define acceptable values, offering more flexibility than AllowedValues.

Example: "AllowedPattern": "[a-zA-Z0-9]*" (Allows only a–z, A–Z, and 0–9 with any length)

MinLength, MaxLength: Used with the String type to set minimum and maximum length constraints.

MinValue, MaxValue: Applied with the Number type to establish lower and upper bounds.

Understanding and utilizing these properties ensures fine-tuned customization and validation when working with CloudFormation parameters.

Q15: What Are Some Cloudformation Parameter Types, and How Are They Utilized?

Ans. CloudFormation parameter types include:

• String, CommaDelimitedList: Represents a string or a list of strings separated by commas.
• Number, List: Represents an integer or float or a list of integers or floats.
• AWS::EC2::Instance::Id, ListAWS::EC2::Instance::Id: Represents an EC2 instance ID (virtual server) or a list of EC2 instance IDs.
• AWS::EC2::Image::Id, ListAWS::EC2::Image::Id: Represents an AMI ID or a list of AMIs.
• AWS::EC2::KeyPair::KeyName: Represents an Amazon EC2 key-pair name.
• AWS::EC2::SecurityGroup::Id, ListAWS::EC2::SecurityGroup::Id: Represents a security group ID or a list of security group IDs.
• AWS::EC2::Subnet::Id, ListAWS::EC2::Subnet::Id: Represents a subnet ID or a list of subnet IDs.
• AWS::EC2::Volume::Id, ListAWS::EC2::Volume::Id: Represents an EBS volume ID (network-attached storage) or a list of EBS volume IDs.
• AWS::EC2::VPC::Id, ListAWS::EC2::VPC::Id: Represents a VPC ID (virtual private cloud) or a list of VPC IDs.
• AWS::Route53::HostedZone::Id, ListAWS::Route53::HostedZone::Id: Represents a DNS zone ID or a list of DNS zone IDs.

These parameter types enable precise input validation for different resource types within CloudFormation templates.

Conclusion

Building your AWS infrastructure through programming is crucial for organized and efficient management. This programming-focused approach ensures reliable, scalable, and agile management of AWS resources, following best practices. Explore JanBask Training AWS Courses for comprehensive learning and hands-on practice, enabling you to master AWS infrastructure programming and excel in cloud computing careers.