53 AWS EC2 interview questions to ask your candidates

As a recruiter or hiring manager, finding the right AWS EC2 talent can be challenging without the proper interview questions. Effective AWS EC2 interview questions help you assess candidates' knowledge and expertise, ensuring you make informed hiring decisions.

This blog post provides a comprehensive list of AWS EC2 interview questions and answers for various skill levels and specializations. From basic concepts to advanced topics like networking, security, and instance management, we cover all aspects of EC2 to help you evaluate candidates thoroughly.

By using these questions, you can confidently assess applicants' AWS EC2 proficiency and make better hiring choices. Consider pairing these interview questions with an AWS skills assessment to get a complete picture of candidates' abilities before the interview stage.

Table of contents

16 basic AWS EC2 interview questions and answers to assess applicants

To evaluate the foundational knowledge of applicants regarding AWS EC2, consider using these essential interview questions. They will help you gauge both technical understanding and practical skills, ensuring you find the right candidate for your cloud engineer job description.

1. What is Amazon EC2 and how does it differ from traditional hosting?
2. Can you explain the concept of instances and instance types in EC2?
3. What are the different pricing models available for EC2 instances?
4. How do you monitor the performance of your EC2 instances?
5. What are security groups in EC2, and how do they work?
6. Explain the difference between EBS and instance store.
7. How can you scale EC2 instances to handle varying loads?
8. What is an AMI and what role does it play in launching an EC2 instance?
9. How do you secure your EC2 instances against unauthorized access?
10. What are the steps to take a snapshot of an EBS volume?
11. Can you describe the process of launching an EC2 instance?
12. What is the difference between vertical scaling and horizontal scaling in EC2?
13. How can you automate the deployment of EC2 instances?
14. What are IAM roles and how do they relate to EC2 instances?
15. How do you handle data backups for EC2 instances?
16. What tools or services can you use to manage multiple EC2 instances effectively?

8 AWS EC2 interview questions and answers to evaluate junior engineers

To effectively evaluate junior engineers for their understanding of AWS EC2, consider using these curated interview questions. Perfect for face-to-face interviews, they will help you gauge the candidate's grasp of essential concepts and ensure they have the foundational knowledge to thrive in your team.

1. Can you explain the key benefits of using Amazon EC2 for cloud computing?

Amazon EC2 offers several key benefits for cloud computing, including scalability, cost-efficiency, and flexibility. It allows businesses to quickly scale their computing capacity up or down depending on demand, which can help manage costs effectively.

Another significant benefit is the variety of instance types available, which allows users to choose the best configuration for their specific needs, whether it's for high memory or high CPU tasks. This flexibility is crucial for optimizing performance and cost.

Look for candidates to discuss multiple benefits and provide real-world examples of how these features can be advantageous. They should also demonstrate an understanding of how these benefits align with business objectives.

2. How do you manage the lifecycle of an EC2 instance?

Managing the lifecycle of an EC2 instance involves several stages including launching, configuring, monitoring, and terminating the instance. Initially, you launch an instance by selecting the appropriate AMI and instance type, then configure it as needed.

Monitoring is typically done using CloudWatch to keep an eye on performance metrics and set alarms for critical thresholds. Finally, when the instance is no longer needed, it can be terminated to stop incurring costs.

A strong candidate will detail each stage clearly, emphasizing the importance of monitoring and resource management. They should also mention tools and best practices they have used to manage EC2 instances effectively.

3. What strategies would you use to optimize costs when using EC2 instances?

Optimizing costs for EC2 instances can involve several strategies. One common approach is to use Reserved Instances for predictable workloads as they offer significant discounts over On-Demand pricing. For less predictable workloads, Spot Instances can be used to take advantage of unused EC2 capacity at reduced rates.

Another strategy is to right-size instances by regularly reviewing and adjusting instance types and sizes based on performance and utilization metrics. Additionally, using Auto Scaling to automatically adjust capacity can help ensure you are only paying for what you need.

Watch for candidates who can explain different cost optimization strategies and provide examples of when to use each. They should also be familiar with tools and reports, such as AWS Cost Explorer, to track and manage expenses.

4. How do you ensure high availability for applications running on EC2?

Ensuring high availability for applications on EC2 involves deploying instances across multiple Availability Zones (AZs) and using Elastic Load Balancing (ELB) to distribute traffic evenly. This setup helps mitigate the risk of downtime due to failures in a single AZ.

Another key component is using Auto Scaling to automatically adjust the number of running instances to handle changes in load and recover from instance failures. Additionally, regularly backing up data and using multi-AZ deployments for databases can enhance availability.

Candidates should discuss these strategies and ideally mention real-world scenarios where they implemented high availability solutions. Look for an understanding of both the technical setup and the business impact of high availability.

5. What steps would you take to troubleshoot a non-responsive EC2 instance?

To troubleshoot a non-responsive EC2 instance, the first step is to check the instance's system logs and CloudWatch metrics for any abnormal activity or errors. If the instance is still accessible via SSH, further diagnostic commands can be run to identify the issue.

If the instance is completely unresponsive, you may need to stop and start the instance to reset its state. Detaching and reattaching EBS volumes to another instance can also help in recovering data or further diagnosing the problem.

Look for candidates who can outline a clear, step-by-step troubleshooting process and show familiarity with the tools and techniques involved. They should also emphasize the importance of root cause analysis to prevent future occurrences.

6. How can you enhance the security of your EC2 instances?

Enhancing security for EC2 instances involves several best practices. First, using Security Groups to control inbound and outbound traffic and ensuring only necessary ports are open. Implementing IAM roles to manage permissions and avoid using root access keys is also crucial.

Regularly updating and patching instances, enabling encryption for data in transit and at rest, and using tools like AWS Inspector for vulnerability assessment can further enhance security. Multi-factor authentication (MFA) should also be used for accessing AWS Management Console.

Candidates should provide a comprehensive list of security practices and explain the rationale behind each one. They should also demonstrate an understanding of the shared responsibility model and how it applies to securing EC2 instances.

7. What are the common use cases for EC2 Auto Scaling?

EC2 Auto Scaling is commonly used for applications with variable workloads to ensure they can handle peak traffic and scale down during off-peak times to save costs. It is also used for maintaining a fixed number of healthy instances by automatically replacing unhealthy ones.

Another use case is in DevOps environments for automating the scaling of environments during different stages of the software development lifecycle, such as testing and production. This ensures efficient resource utilization and cost management.

Strong candidates will not only list use cases but also provide examples from their experience. They should show an understanding of how Auto Scaling can be configured and monitored to meet different business needs.

8. How would you handle a situation where your EC2 instance is experiencing high latency?

Handling high latency in an EC2 instance starts with identifying the root cause. This could involve checking CloudWatch metrics to pinpoint any resource bottlenecks like CPU or memory usage. Network latency can also be traced using VPC Flow Logs or network performance metrics.

Once the cause is identified, solutions may include optimizing the application code, increasing the instance size, or using placement groups for low-latency communication between instances. Implementing caching mechanisms and optimizing database queries can also help reduce latency.

Candidates should discuss a systematic approach to diagnosing and resolving high latency issues. Look for their ability to articulate different potential causes and corresponding solutions, backed by examples from their experience.

12 intermediate AWS EC2 interview questions and answers to ask mid-tier engineers

To ensure your mid-tier candidates have the necessary skills to manage AWS EC2 instances effectively, consider using these intermediate-level questions. These queries are designed to probe deeper into their technical understanding and practical experience, helping you identify the best fit for your AWS developer job description.

1. Can you explain how EC2 Spot Instances work and what are their advantages?
2. What is the difference between an Elastic IP and a regular public IP address in EC2?
3. How do you use Elastic Load Balancing with EC2 to ensure better application performance?
4. What steps would you take to migrate an on-premise application to AWS EC2?
5. How do you handle EC2 instance termination protection?
6. Describe the process of attaching an EBS volume to a running EC2 instance.
7. What are the benefits and drawbacks of using EC2 Dedicated Hosts?
8. How do you configure user data and metadata for an EC2 instance?
9. Can you explain the concept of EC2 Reserved Instances and when you would use them?
10. How do you implement fault tolerance and redundancy for your EC2 instances?
11. What strategies can you use to manage EC2 instance state transitions effectively?
12. How do you optimize the performance of an EC2 instance for a database workload?

7 AWS EC2 interview questions and answers related to networking and security

To gauge whether your candidates have the essential networking and security knowledge for Amazon EC2, ask them these 7 targeted interview questions. These questions will help you identify if they can effectively manage and secure EC2 instances in a real-world setting.

1. How does VPC (Virtual Private Cloud) work with EC2?

A Virtual Private Cloud (VPC) allows you to create a virtual network within AWS where you can launch your EC2 instances. The VPC provides you with complete control over your network configuration, including selection of IP address range, creation of subnets, and configuration of route tables and network gateways.

You can segment your VPC into public and private subnets, ensuring that your sensitive data remains secured in private subnets while your public-facing resources can be accessed via the public subnet.

Look for candidates to explain the fundamental elements of VPC and how it enhances security and network management for EC2 instances. An ideal response should include details about subnets, security groups, and route tables.

2. Explain the role and benefits of using an Elastic IP with EC2 instances.

An Elastic IP address is a static IPv4 address created for dynamic cloud computing. You can associate it with any EC2 instance in your account, allowing you to mask the failure of an instance by rapidly remapping the address to another instance in your VPC.

Elastic IPs are especially useful in scenarios where you need a persistent endpoint for your applications, even if the underlying instance changes. This ensures that users and services can always find your application at the same IP address.

Candidates should highlight the importance of Elastic IPs for maintaining continuity and minimizing downtime in cloud environments. Look for an understanding of how to allocate, associate, and manage Elastic IPs effectively.

3. What are Network ACLs and how do they differ from Security Groups in AWS EC2?

Network ACLs (Access Control Lists) are an optional layer of security for your VPC that acts as a firewall for controlling traffic in and out of one or more subnets. They operate at the subnet level and can allow or deny specific IP addresses or ports.

Security Groups, on the other hand, operate at the instance level and control inbound and outbound traffic for your EC2 instances. While Security Groups are stateful (return traffic is automatically allowed regardless of outbound rules), Network ACLs are stateless (return traffic must be explicitly allowed by rules).

An ideal candidate should clearly differentiate between the two and explain scenarios where each would be appropriate. They should also demonstrate knowledge of rule hierarchy and default behavior for both security mechanisms.

4. How can you protect your EC2 instances against DDoS attacks?

To protect EC2 instances against DDoS (Distributed Denial of Service) attacks, AWS provides several tools and services. AWS Shield is a managed DDoS protection service that safeguards applications running on AWS. AWS WAF (Web Application Firewall) helps protect your web applications from common web exploits.

Additionally, configuring Security Groups and Network ACLs to restrict unauthorized traffic, and using CloudFront for content delivery and additional DDoS mitigation, are effective strategies.

Look for candidates to mention specific AWS services like AWS Shield and AWS WAF, and to explain how these services integrate with EC2 to provide comprehensive protection. They should also discuss best practices for configuring security settings to mitigate potential DDoS threats.

5. What is a Bastion Host and how is it used in securing EC2 instances?

A Bastion Host is a special-purpose server that acts as a gateway between your private network and the outside world. It provides secure access to your EC2 instances without exposing them directly to the internet.

Typically, you would place a Bastion Host in a public subnet, allowing SSH or RDP access through this host, while your actual EC2 instances remain in private subnets, reducing their exposure to potential threats.

Candidates should articulate the role of a Bastion Host in enforcing security and minimizing the attack surface. They should also discuss best practices for configuring and maintaining a Bastion Host, such as using key pairs for authentication and restricting access to specific IP ranges.

6. How does AWS Direct Connect enhance network security for EC2 instances?

AWS Direct Connect is a dedicated network connection from your premises to AWS, providing a private and secure link to your VPC and EC2 instances. This dedicated connection reduces your reliance on the public internet, thereby enhancing security and reducing latency.

By using Direct Connect, you can establish private connectivity to your AWS environment, which is ideal for applications that require high throughput and low latency. It also allows for better control over your network traffic and data transfer costs.

Ideal responses should cover the security benefits of using Direct Connect, such as avoiding the public internet and enabling secure, consistent network performance. Candidates should also mention use cases where Direct Connect would be particularly advantageous.

7. What is the Shared Responsibility Model in AWS, and how does it apply to EC2 security?

The Shared Responsibility Model in AWS delineates the security responsibilities between AWS and the user. AWS is responsible for 'security of the cloud' (infrastructure, hardware, and software), while the user is responsible for 'security in the cloud' (data, applications, and instance configurations).

For EC2, this means AWS handles the security of the physical infrastructure, while users must secure their own instances, including managing access controls, configuring firewalls, and ensuring data protection.

Candidates should demonstrate a clear understanding of this model and be able to articulate specific responsibilities for EC2 instances. Look for awareness of user responsibilities such as patch management, access management, and data encryption.

10 AWS EC2 interview questions about instance management

To assess a candidate's proficiency in AWS EC2 instance management, use these 10 interview questions. They cover key aspects of EC2 instance handling, helping you evaluate an applicant's practical knowledge and problem-solving skills in real-world scenarios.

1. How would you approach resizing an EC2 instance without data loss?
2. Explain the process of creating a custom AMI from a running EC2 instance.
3. What steps would you take to migrate an EC2 instance to a different AWS region?
4. How can you schedule automatic start and stop times for EC2 instances?
5. Describe the process of attaching multiple network interfaces to an EC2 instance.
6. What strategies would you use to optimize the boot time of an EC2 instance?
7. How do you handle EC2 instance recovery in case of an underlying hardware failure?
8. Explain the process of setting up cross-region replication for EC2 instances.
9. How would you implement automated patching for a fleet of EC2 instances?
10. What steps would you take to troubleshoot high CPU utilization on an EC2 instance?

Which AWS EC2 skills should you evaluate during the interview phase?

When evaluating candidates for a position that requires expertise in AWS EC2, it's important to understand that no single interview can cover every aspect of a candidate's skills. Instead, focus on a few core competencies that are fundamental to working with AWS EC2. These skills will help you gauge the candidate's proficiency and their ability to handle real-world tasks effectively.

Instance Management

Instance management is the backbone of AWS EC2. It involves the creation, configuration, and termination of instances, which are the virtual servers running your applications. Proficiency in instance management ensures that the candidate can efficiently handle the lifecycle of EC2 instances.

You can use an assessment test with relevant MCQs to filter out this skill. For instance, our AWS online test includes questions on instance management.

In addition to tests, consider asking targeted interview questions to evaluate this skill.

How do you handle the scaling of EC2 instances to match the demand of your application?

When this question is asked, look for specifics on auto-scaling groups, manual scaling, and the use of CloudWatch for monitoring. The candidate should demonstrate a clear understanding of scaling strategies and their practical applications.

Networking and Security

Understanding networking and security is crucial for any AWS EC2 user. This skill involves configuring VPCs, setting up security groups, and managing network access. It ensures that the candidate can create secure and reliable network architectures.

You can use an assessment test with relevant MCQs to filter out this skill. For instance, our AWS online test includes questions on networking and security.

In addition to tests, consider asking targeted interview questions to evaluate this skill.

Describe how you would secure an EC2 instance that hosts a web application.

Look for answers that include the use of security groups, NACLs, IAM roles, and encryption. The candidate should be able to articulate best practices for securing EC2 instances.

Cost Management

Effective cost management is essential when working with AWS EC2 to avoid unnecessary expenses. This skill involves understanding pricing models, optimizing resource usage, and leveraging cost-saving tools like Reserved Instances and Spot Instances.

You can use an assessment test with relevant MCQs to filter out this skill. Our AWS online test includes questions on cost management.

In addition to tests, consider asking targeted interview questions to evaluate this skill.

How do you optimize the cost of running multiple EC2 instances?

When this question is asked, expect the candidate to discuss Reserved Instances, Spot Instances, and resource monitoring. They should demonstrate an understanding of cost-saving strategies and the tools available in AWS for cost management.

Enhance Your Team with Top AWS EC2 Talent Using Adaface

When hiring professionals skilled in AWS EC2, confirming their expertise is key. The right skill set ensures they can handle specific job requirements effectively.

The most direct way to assess these skills is through targeted tests. Consider using Adaface's AWS DevOps Test or the AWS Online Test to evaluate candidates accurately.

After administering these tests, you can efficiently shortlist the top candidates. This process ensures that only the most capable applicants proceed to the interview stage.

To get started with this streamlined hiring process, you can sign up here or learn more about our offerings on the Adaface Online Assessment Platform page.

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