Mastering the AWS Interview: Top Frequently Asked Questions and Answers

The pre-appearing phase of an AWS interview is a bit tricky. Don’t you think?

You study the nook and corners of each and every topic, you get trained properly to answer all the questions, you keep memorizing everything in your head over and over again. Yet, it is a constant that you get sweaty palms every time you appear for an interview. 

It would have been great if you could have an idea about the interview questions beforehand. Isn’t it? 

Well, if you are going to sit for an AWS interview at any point this year, then we have those solutions ready for you! Here are the top 25 AWS interview questions along with their answers, that every interviewer loves to ask their candidates. Have a look!

 AWS Interview: Answers to Top 25 Frequently Asked Questions

1. Define and explain the three basic types of cloud services and the AWS products that are built based on them?

Ans. There are 3 basic types of cloud services in total:

• Computing 
• Storage
• Networking

There are a few AWS products that are built based on these services. They are as follows:

• Computing:  EC2, Elastic Beanstalk, Lambda, Auto-Scaling, and Lightsat are based on computing
• Storage:  S3, Glacier, Elastic Block Storage, Elastic File System are based on storage
• Networking: VPC, Amazon CloudFront, Route53 are based on networking

 

2. What is the difference between the Availability Zone and Region?

Ans. AWS Regions are segregated geographical areas. Availability zones denote the areas that are present inside the areas that are mainly isolated zones and can replicate themselves according to the requirement. 

3. Define auto-scaling.

Ans. AWS Auto Scaling monitors your applications and automatically adjusts the capacity to maintain steady, predictable performance at the lowest possible cost. Using AWS Auto Scaling, it’s easy to setup application scaling for multiple resources across multiple services in minutes. The service provides a simple, powerful user interface that lets you build scaling plans for resources.

4. What is geo-targeting in the cloud front?

Ans. In CloudFront, we can detect the country from where end users are requesting our content. After passing the information to the Origin server by Amazon CloudFront through a new HTTP header, based on different countries we can generate different content for different versions of the same content. These versions can be cached at different Edge Locations that are closer to the end-users of that country. In this way, we can target our end-users based on their geographic locations.

5. What are the steps involved in a CloudFormation Solution?

Ans. 4 steps are involved in the CloudFormation Solution. They are as follows:

1. Create or use an existing CloudFormation template with the help of JSON or YAML format.
2. Save the code in an S3 bucket that serves as a repository for the code.
3. Use AWS CloudFormation to call the bucket and create a stack on your template. 
4. CloudFormation reads the file and understands the services by order, the relationship between them, and provisions the services one after another.

6. How do you upgrade or downgrade a system with near-zero downtime?

Ans: The only way to upgrade or downgrade a system with near-zero downtime is by using the following steps of migration:

• Open EC2 console
• Choose Operating System AMI
• Launch an instance with the new instance type
• Install the updates
• Install applications
• Test the instance and make sure that it’s working
• Deploy the new instance and replace the older instance
• After Deploying the new instance you can upgrade or downgrade the system with near-zero downtime.

7. Is there any other alternative tool to log into the cloud environment other than console?

Ans. Few tools that can help you to log into the cloud environment are:

• Putty
• AWS CLI for Linux
• AWS CLI for Windows
• AWS CLI for Windows CMD
• AWS SDK
• Eclipse

8. What is a DDoS attack, and what services can minimize them?

Ans. DDoS is a cyber-attack. In this particular cyberattack, the perpetrator accesses a website and creates multiple sessions. This way, no other legitimate users cannot access the service. Some native tools that can help you deny the DDoS attacks on your AWS services are:

• AWS Shield
• AWS WAF
• Amazon Route53
• Amazon CloudFront
• ELB
• VPC

9. How do you set up a system to monitor website metrics in real-time in AWS?

Ans. Amazon CloudWatch helps you to monitor:

• State changes in Amazon EC2
• Auto-scaling lifecycle events
• Scheduled events
• AWS API calls
• Console sign-in events

And in this way, it helps you to monitor the application status of various AWS services and custom events as well.

10. Name some of the AWS services that are not region-specific

Ans. Following AWS services are not region-specific:

• IAM
• Route 53
• Web Application Firewall 
• CloudFront

11. What are the different types of EC2 instances based on their costs?

Ans. There are 3 types of EC2 instances:

• On-demand Instance:
  This is pocket-friendly for a short time, but not for the long run.
• Spot Instance:
  Less expensive than the on-demand instance. You can buy it through bidding as well.  
• Reserved Instance
  This one is the right instance to use for a year or more.

12. How do you set up SSH agent forwarding so that you do not have to copy the key every time you log in?

Ans. These are the steps you can follow to set up SSH agent forwarding without copying the key every time you log in:

1. Go to your PuTTY Configuration
2. Go to the category SSH -> Auth
3. Enable SSH agent forwarding to your instance

13. What are the Solaris and AIX operating systems? Are they available with AWS?

Ans. Solaris is an operating system that uses SPARC processor architecture. It is currently not supported by the public cloud. 

AIX is another operating system that runs only on Power CPU and not on Intel. For this reason, you cannot create AIX instances in EC2.

Since both operating systems have their limitations, they are not currently available with AWS.

14. How do you configure CloudWatch to recover an EC2 instance?

Ans. These steps will help you in configuring CloudWatch to recover an EC2 instance:

• Create an Alarm using Amazon CloudWatch
• In the Alarm, go to Define Alarm -> Actions tab
• Choose Recover this instance option

15. What are the common types of AMI designs?

Ans. Among many types of AMIs, these 3 are the most common:

• Fully Baked AMI
• Just Enough Baked AMI (JeOS AMI)
• Hybrid AMI

16. How can you recover or log in to an EC2 instance for which you have lost the key?

Ans. You can follow these steps to do the same:

1. Verify that the EC2Config service is running
2. Detach the root volume for the instance
3. Attach the volume to a temporary instance
4. Modify the configuration file
5. Restart the original instance

17. How do you allow a user to gain access to a specific bucket?

Ans. You need to follow these 4 steps to give a user access to a specific bucket:

1. Categorize your instances
2. Define how authorized users can manage specific servers.
3. Lockdown your tags
4. Attach your policies to IAM users

18. VPC is not resolving the server through DNS. What might be the issue, and how can you fix it?

Ans. You need to enable DNS hostname resolution. By doing that, the problem gets resolved on its own.

19. How do you monitor Amazon VPC?

Ans. VPC can be monitored with the help of:

• CloudWatch and CloudWatch logs
• VPC Flow Logs

20. What are the factors to consider while migrating to Amazon Web Services?

Ans. When you are migrating to AWS, these following factors create a huge impact:

• Operational Costs (including the cost of infrastructure, the ability to match demand and supply, transparency, and others)
• Workforce Productivity 
• Cost avoidance
• Operational resilience
• Business agility

21. What is RTO and RPO in AWS?

Ans. RTO, or Recovery Time Objective, is the maximum waiting time of your organization for recovery to complete in the wake of an outage. 

RPO or Recovery Point Objective, is the maximum amount of data loss your company is willing to accept when measured in time.

22. What are the elements of an AWS CloudFormation template?

Ans. AWS CloudFormation templates are YAML or JSON-formatted text files. They are made of these following 5 essential elements:

• Template parameters
• Output values
• Data tables
• Resources
• File format version

23. How can you automate EC2 backup using EBS?

Ans. The following steps will help you automate EC2 backup using EBS:

1. Get the list of instances and connect to AWS through API to list the Amazon EBS volumes that are attached locally to the instance.
2. List the snapshots of each volume, and assign a retention period of the snapshot. Once that is done, create a snapshot of each volume.
3. Remove the snapshot if it is older than the retention period.

24. What is the difference between EBS and Instance Store?

Ans. EBS is permanent storage in which the data can be restored at some future point. When you save data in the EBS, it stays even after the lifetime of the EC2 instance is over. 

On the other hand, Instance Store is temporary storage that is physically attached to a host machine. You cannot detach one instance and attach it to another with the help of it. Data in an Instance Store is lost forever if any instance has been terminated.

25. How do you auto-delete old snapshots?

Ans. By following these steps, you can auto-deleting old snapshots:

• Take snapshots of the EBS volumes on Amazon S3.
• Use AWS Ops Automator to handle all the snapshots automatically.
• This allows you to create, copy, and delete Amazon EBS snapshots.

Conclusion:

Feeling a little more confident about cracking an AWS interview now?

Well, this is just a teaser! You can get a lot more than these AWS interview questions. Where may you ask? Well, the place is our AWS training sessions, the time and other details you can find out right here! Plus, you know that an AWS certification can always make you two steps ahead of your competitors. Isn’t it? So hurry up, and get one for yourself too!

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