Episode 61: Amazon AWS EC2 Instances and Best Practices

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

AWS services that are not region-specific are:

• IAM
• Route 53
• Web Application Firewall 
• CloudFront

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16. What are the differences between NAT Gateways and NAT Instances?

While both NAT Gateways and NAT Instances serve the same function, they still have some key differences.

17. What is CloudWatch?

The Amazon CloudWatch has the following features:

• Depending on multiple metrics, it participates in triggering alarms.
• Helps in monitoring the AWS environments like CPU utilization, EC2, Amazon RDS instances, Amazon SQS, S3, Load Balancer, SNS, etc.

18. What is an Elastic Transcoder?

To support multiple devices with various resolutions like laptops, tablets, and smartphones, we need to change the resolution and format of the video. This can be done easily by an AWS Service tool called the Elastic Transcoder, which is a media transcoding in the cloud that exactly lets us do the needful. It is easy to use, cost-effective, and highly scalable for businesses and developers.

AWS Interview Questions for Amazon EC2

19. What is Amazon EC2?

EC2 is short for Elastic Compute Cloud, and it provides scalable computing capacity. Using Amazon EC2 eliminates the need to invest in hardware, leading to faster development and deployment of applications. You can use Amazon EC2 to launch as many or as few virtual servers as needed, configure security and networking, and manage storage. It can scale up or down to handle changes in requirements, reducing the need to forecast traffic. EC2 provides virtual computing environments called “instances.”

20. What Are Some of the Security Best Practices for Amazon EC2?

Security best practices for Amazon EC2 include using Identity and Access Management (IAM) to control access to AWS resources; restricting access by only allowing trusted hosts or networks to access ports on an instance; only opening up those permissions you require, and disabling password-based logins for instances launched from your AMI.

21. Can S3 Be Used with EC2 Instances, and If Yes, How?

Amazon S3 can be used for instances with root devices backed by local instance storage. That way, developers have access to the same highly scalable, reliable, fast, inexpensive data storage infrastructure that Amazon uses to run its own global network of websites. To execute systems in the Amazon EC2 environment, developers load Amazon Machine Images (AMIs) into Amazon S3 and then move them between Amazon S3 and Amazon EC2.

Amazon EC2 and Amazon S3 are two of the best-known web services that make up AWS.

22. What is the difference between stopping and terminating an EC2 instance? 

While you may think that both stopping and terminating are the same, there is a difference. When you stop an EC2 instance, it performs a normal shutdown on the instance and moves to a stopped state. However, when you terminate the instance, it is transferred to a stopped state, and the EBS volumes attached to it are deleted and can never be recovered. 

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

The three types of EC2 instances are:

• On-demand Instance

It is cheap for a short time but not when taken for the long term

• Spot Instance

It is less expensive than the on-demand instance and can be bought through bidding. 

• Reserved Instance

If you are planning to use an instance for a year or more, then this is the right one for you.

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

Here’s how you accomplish this:

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

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

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

AIX is an operating system that runs only on Power CPU and not on Intel, which means that you cannot create AIX instances in EC2.

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