AWS AMI Interview Questions

1. What is an AMI? 

An Amazon Machine Image (AMI) is a pre-configured virtual machine image that is used to create instances on the Amazon Elastic Compute Cloud (Amazon EC2). It contains all of the necessary software and configurations that are needed to launch a virtual machine, including the operating system, applications, libraries, and other dependencies.

An AMI is stored in Amazon Simple Storage Service (S3) and can be used to launch an EC2 instance. When you launch an instance from an AMI, the instance will have the same software and configurations as the AMI. This allows you to quickly and easily create new instances that are configured exactly the way you want them to be.

You can choose from a variety of pre-configured AMIs provided by Amazon, or you can create your own custom AMI by launching an EC2 instance from a base image and installing and configuring the software you need. AMIs can be shared with other AWS accounts or made public, allowing others to use them to launch their own instances.

2. What is your understanding of AMI?

An Amazon Machine Image (AMI) is a pre-configured virtual machine image that is used to create instances on the Amazon Elastic Compute Cloud (Amazon EC2). It contains all of the necessary software and configurations that are needed to launch a virtual machine, including the operating system, applications, libraries, and other dependencies.

An AMI is stored in Amazon Simple Storage Service (S3) and can be used to launch an EC2 instance. When you launch an instance from an AMI, the instance will have the same software and configurations as the AMI. This allows you to quickly and easily create new instances that are configured exactly the way you want them to be.

You can choose from a variety of pre-configured AMIs provided by Amazon, or you can create your own custom AMI by launching an EC2 instance from a base image and installing and configuring the software you need. AMIs can be shared with other AWS accounts or made public, allowing others to use them to launch their own instances.

3. Do you think there is a relation between Instance and AMI?

Yes, there is a relationship between an instance and an Amazon Machine Image (AMI). An instance is a virtual machine that is launched from an AMI and runs in the Amazon Elastic Compute Cloud (Amazon EC2). An AMI is essentially a template that is used to create an instance. It contains all of the necessary software and configurations that are needed to launch the instance, including the operating system, applications, libraries, and other dependencies.

When you launch an instance from an AMI, the instance will have the same software and configurations as the AMI. This allows you to quickly and easily create new instances that are configured exactly the way you want them to be.

You can choose from a variety of pre-configured AMIs provided by Amazon, or you can create your own custom AMI by launching an EC2 instance from a base image and installing and configuring the software you need. AMIs can be shared with other AWS accounts or made public, allowing others to use them to launch their own instances.

4. What are the various AMI design options?

There are several design options to consider when creating an Amazon Machine Image (AMI). Here are some of the key options:

1. Base image: You can choose a base image that is provided by Amazon or a community AMI, or you can create your own custom base image by launching an EC2 instance from a base image and installing and configuring the software you need.
2. Software and configurations: After selecting a base image, you can install and configure the software and other dependencies that you need on the instance. This could include applications, libraries, and other dependencies.
3. Instance type: When creating the AMI, you can specify the instance type that the AMI is optimized for. This determines the hardware and performance characteristics of the instance that is launched from the AMI.
4. Region and availability zone: You can specify the region and availability zone where the AMI will be stored and where instances launched from the AMI will be placed.
5. Permissions: You can specify the permissions for the AMI, such as which AWS accounts or users are allowed to launch instances from the AMI.
6. Encryption: You can specify whether the AMI and the instances launched from the AMI should be encrypted, and if so, which encryption keys should be used.
7. Tags: You can assign tags to the AMI to help organize and manage your AMIs.

It’s worth noting that you can also use a third-party tool like Packer to automate the process of building an AMI. Packer allows you to define the steps needed to create an AMI as a configuration file, and then it can execute those steps automatically. This can be helpful if you need to build AMIs on a regular basis or if you want to automate the AMI build process as part of a continuous delivery pipeline.

5. What is the procedure to build an AMI?

An Amazon Machine Image (AMI) is a pre-configured virtual machine image that is used to create instances on the Amazon Elastic Compute Cloud (Amazon EC2). Here is the general procedure to build an AMI:

1. Choose a base image: You can start by selecting a base image that is provided by Amazon or a community AMI. You can also create your own custom AMI by launching an EC2 instance from a base image, installing the software you need, and configuring the instance to your liking.
2. Install and configure the software: Once you have a base image, you can install and configure the software that you need on the instance. This could include applications, libraries, and other dependencies.
3. Create a snapshot: After you have installed and configured the software on the instance, you can create a snapshot of the instance’s root volume. This snapshot will be used to create the AMI.
4. Create the AMI: Using the snapshot that you created, you can create an AMI through the Amazon EC2 console, the AWS CLI, or the Amazon EC2 API. When creating the AMI, you can specify various options, such as the name and description of the AMI, the instance type that the AMI is optimized for, and the permissions for the AMI.
5. Launch an instance from the AMI: Once you have created the AMI, you can launch an EC2 instance from the AMI. This will create a new instance that is based on the AMI, and the instance will have all of the software and configurations that you specified when you created the AMI.

It’s worth noting that you can also use a third-party tool like Packer to automate the process of building an AMI. Packer allows you to define the steps needed to create an AMI as a configuration file, and then it can execute those steps automatically. This can be helpful if you need to build AMIs on a regular basis or if you want to automate the AMI build process as part of a continuous delivery pipeline.

6. Name the types of AMI provided by AWS.

There are several types of Amazon Machine Images (AMIs) provided by Amazon Web Services (AWS):

1. Amazon Linux AMIs: These AMIs are based on the Amazon Linux operating system and are optimized for use on Amazon EC2. They include support for multiple languages and tools, such as Python, Ruby, and Node.js.
2. Windows AMIs: These AMIs are based on the Windows operating system and include a license for Windows Server. They can be used to launch instances that are running a variety of Windows operating systems, including Windows Server, Windows Server with SQL Server, and Windows Server with Remote Desktop Services.
3. Community AMIs: These AMIs are created and shared by the AWS community and can be used to launch instances. Community AMIs are not supported by AWS, but they can be a useful source of pre-configured AMIs for a variety of purposes.
4. Marketplace AMIs: These AMIs are provided by third-party vendors and are available for purchase through the AWS Marketplace. They can be used to launch instances that are pre-configured with a variety of software and applications, such as databases, development tools, and business applications.
5. Custom AMIs: You can create your own custom AMI by launching an EC2 instance from a base image and installing and configuring the software you need. Custom AMIs can be shared with other AWS accounts or made public, allowing others to use them to launch their own instances.

7. How to update AMI tools at the Boot-Time on Linux?

To update the AMI tools at boot time on a Linux instance, you can use the following steps:

1. Connect to your Linux instance using SSH.
2. Create a script that updates the AMI tools. You can use the following script as a starting point:

#!/bin/bash

# Update the package manager
apt-get update

# Install the latest version of the AMI tools
apt-get install -y ec2-ami-tools

3. Save the script to a file, such as update-ami-tools.sh
4. Make the script executable by running the following command:

chmod +x update-ami-tools.sh

5. Add the script to the /etc/rc.local file so that it will be run at boot time. Open the file and add the following line before the exit 0 line:

/path/to/update-ami-tools.sh

6. Save the changes to the /etc/rc.local file and exit.
7. Restart the instance to apply the changes. The AMI tools will be updated at boot time.

It’s worth noting that the exact steps to update the AMI tools may vary depending on your Linux distribution and the version of the AMI tools that you are using. You may need to modify the script and the commands used to install the AMI tools accordingly.

8. Can you explain what an AMI is?

An Amazon Machine Image (AMI) is a pre-configured virtual machine image that is used to create instances on the Amazon Elastic Compute Cloud (Amazon EC2). It contains all of the necessary software and configurations that are needed to launch a virtual machine, including the operating system, applications, libraries, and other dependencies.

An AMI is stored in Amazon Simple Storage Service (S3) and can be used to launch an EC2 instance. When you launch an instance from an AMI, the instance will have the same software and configurations as the AMI. This allows you to quickly and easily create new instances that are configured exactly the way you want them to be.

You can choose from a variety of pre-configured AMIs provided by Amazon, or you can create your own custom AMI by launching an EC2 instance from a base image and installing and configuring the software you need. AMIs can be shared with other AWS accounts or made public, allowing others to use them to launch their own instances.

9. What’s the difference between an Amazon Machine Image and a virtual machine image?

An Amazon Machine Image (AMI) is a pre-configured virtual machine image that is used to create instances on the Amazon Elastic Compute Cloud (Amazon EC2). It contains all of the necessary software and configurations that are needed to launch a virtual machine, including the operating system, applications, libraries, and other dependencies.

A virtual machine image, on the other hand, is a file that contains the necessary information to create a virtual machine on a hypervisor, such as VMware vSphere or Microsoft Hyper-V. Virtual machine images typically include the operating system, applications, libraries, and other dependencies that are needed to run the virtual machine.

There are some key differences between AMIs and virtual machine images:

1. Compatibility: AMIs are specifically designed to be used with Amazon EC2, while virtual machine images can be used with a variety of hypervisors.
2. Storage: AMIs are stored in Amazon Simple Storage Service (S3), while virtual machine images can be stored on a variety of storage media, such as local disk, network-attached storage (NAS), or storage area network (SAN).
3. Deployment: AMIs are used to launch instances on Amazon EC2, while virtual machine images can be used to create virtual machines on a variety of hypervisors.
4. Management: AMIs are managed through the Amazon EC2 console, API, or command-line interface (CLI), while virtual machine images are typically managed through the tools provided by the hypervisor.

It’s worth noting that there are also some similarities between AMIs and virtual machine images. Both types of images can be used to create virtual machines that are pre-configured with the necessary software and dependencies, and both can be customized and modified to meet specific needs.

10. How can I create my own AMI?

You can create your own Amazon Machine Image (AMI) by following these steps:

1. Launch an EC2 instance from a base image: Choose a base image that is provided by Amazon or a community AMI, or create your own custom base image by launching an EC2 instance from a base image and installing and configuring the software you need.
2. Install and configure the software: Once you have a base image, you can install and configure the software that you need on the instance. This could include applications, libraries, and other dependencies.
3. Create a snapshot: After you have installed and configured the software on the instance, you can create a snapshot of the instance’s root volume. This snapshot will be used to create the AMI.
4. Create the AMI: Using the snapshot that you created, you can create an AMI through the Amazon EC2 console, the AWS CLI, or the Amazon EC2 API. When creating the AMI, you can specify various options, such as the name and description of the AMI, the instance type that the AMI is optimized for, and the permissions for the AMI.
5. Launch an instance from the AMI: Once you have created the AMI, you can launch an EC2 instance from the AMI. This will create a new instance that is based on the AMI, and the instance will have all of the software and configurations that you specified when you created the AMI.

It’s worth noting that you can also use a third-party tool like Packer to automate the process of building an AMI. Packer allows you to define the steps needed to create an AMI as a configuration file, and then it can execute those steps automatically. This can be helpful if you need to build AMIs on a regular basis or if you want to automate the AMI build process as part of a continuous delivery pipeline.

11. Is it possible to launch multiple EC2 instances from one AMI? If yes, how?

Yes, it is possible to launch multiple Amazon Elastic Compute Cloud (EC2) instances from a single Amazon Machine Image (AMI). To do this, you can use the Amazon EC2 console, the AWS command-line interface (CLI), or the Amazon EC2 API.

Here is an example of how to launch multiple EC2 instances from an AMI using the Amazon EC2 console:

1. Sign in to the AWS Management Console and open the Amazon EC2 console.
2. In the navigation pane, choose Instances, and then choose Launch Instances.
3. Select the AMI that you want to use to launch the instances.
4. Choose the instance type and configure the other instance details, such as the number of instances, the network and security settings, and the key pair.
5. Review the details of the instances that you are launching, and then choose Launch.
6. When prompted, select an existing key pair or create a new key pair, and then choose Launch Instances.

The instances will be launched from the AMI, and they will have the same software and configurations as the AMI. You can view the status of the instances in the Amazon EC2 console or by using the AWS CLI or the Amazon EC2 API.

It’s worth noting that you can also use the AWS Auto Scaling service to launch multiple EC2 instances from an AMI. AWS Auto Scaling allows you to automatically scale your EC2 fleet up or down based on demand, and it can be configured to launch instances from a specific AMI. This can be helpful if you need to scale your EC2 fleet quickly and automatically.

12. What are some of the ways that you can use to share your AMIs with others?

There are several ways that you can use to share your Amazon Machine Images (AMIs) with others:

1. Share with specific AWS accounts: You can share your AMIs with specific AWS accounts using the Amazon Elastic Compute Cloud (Amazon EC2) console, the AWS command-line interface (CLI), or the Amazon EC2 API. When you share an AMI with another AWS account, the owner of the account will be able to view and launch instances from the AMI.
2. Make the AMI public: You can make your AMI public so that anyone can view and launch instances from the AMI. To do this, you can use the Amazon EC2 console, the AWS CLI, or the Amazon EC2 API.
3. Use AWS Marketplace: You can use the AWS Marketplace to sell or distribute your AMIs to a wider audience. The AWS Marketplace is an online store where customers can browse and purchase a variety of software and services, including AMIs.
4. Share a link to the AMI: You can share a link to the AMI with others so that they can view the AMI and launch instances from it. To get the link to the AMI, you can use the Amazon EC2 console, the AWS CLI, or the Amazon EC2 API.

It’s worth noting that you can also use a third-party tool like Packer to automate the process of building and sharing AMIs. Packer allows you to define the steps needed to create an AMI as a configuration file, and then it can execute those steps automatically. This can be helpful if you need to build and share AMIs on a regular basis or if you want to automate the AMI build and sharing process as part of a continuous delivery pipeline.

13. What do you understand about the IAM root device volume for an instance backed by an EBS volume?

In Amazon Web Services (AWS), an IAM (Identity and Access Management) root device volume is a virtual device that is automatically created and attached to an EC2 (Elastic Compute Cloud) instance when it is launched. The root device volume contains the root file system for the instance, which is the file system that the instance boots from. It is typically an Amazon Elastic Block Store (EBS) volume.

When an EC2 instance is launched, the root device volume is created and attached to the instance, and the instance is configured to boot from the root device volume. The root device volume is the default location for the operating system, system libraries, and application files for the instance. It is also the default location for system logs and other system files.

The size of the root device volume can be specified when the instance is launched, and it can be increased or decreased as needed. The root device volume can also be backed up using Amazon Elastic Block Store Snapshots.

It’s important to note that the root device volume is distinct from any additional EBS volumes that may be attached to the instance. These additional EBS volumes can be used to store data and can be attached and detached from the instance as needed, but they are not used to boot the instance.

14. How can you make sure that no other user launches an AMI that you have created?

There are several ways you can make sure that no other user launches an Amazon Machine Image (AMI) that you have created:

1. Use IAM policies to control access to AMIs: You can use IAM policies to grant or deny permissions to users or groups to launch AMIs. For example, you can create an IAM policy that only allows a specific user or group to launch a specific AMI.
2. Use resource-level permissions: You can use resource-level permissions to specify which AMIs a user or group can launch. This can be done by adding a condition to an IAM policy that checks the AMI ID.
3. Use Amazon EC2 launch permissions: You can use Amazon EC2 launch permissions to specify which AMIs a user or group can launch. Launch permissions are associated with an AMI, and you can specify which users or groups are allowed to launch the AMI.
4. Use Amazon EC2 instance profile permissions: You can use Amazon EC2 instance profile permissions to specify which actions a user or group can perform on an instance. This can be done by adding a condition to an IAM policy that checks the instance profile.

It’s important to note that these methods can be used in combination to provide the level of access control that you need. It’s also important to regularly review and update your IAM policies to ensure that they continue to meet your security and compliance requirements.

15. What is the best way to ensure data security when using AWS services like S3 or Glacier?

Here are some ways to ensure data security when using Amazon Web Services (AWS) AMI services like Amazon Simple Storage Service (S3) or Amazon S3 Glacier:

1. Use encryption: You can use server-side encryption or client-side encryption to protect your data at rest and in transit.
2. Use access controls: You can use AWS Identity and Access Management (IAM) to set fine-grained access controls on your S3 buckets and objects, ensuring that only authorized users can access your data.
3. Use multi-factor authentication: You can enable multi-factor authentication (MFA) for your AWS account to add an extra layer of security when accessing your AWS resources.
4. Monitor access: You can use AWS CloudTrail to track and log all API calls made to your AWS account, allowing you to monitor access to your resources and identify any unauthorized access attempts.
5. Use secure networks: You can use Virtual Private Clouds (VPCs) and Secure Sockets Layer (SSL) to establish secure networks and protect your data in transit.
6. Regularly review and update your security measures: It is important to regularly review and update your security measures to ensure that your data remains secure. This includes updating your encryption keys, rotating your access keys, and reviewing your IAM policies.

In addition, when using AMI services like S3 Glacier, you should also be aware of the security measures that are in place to protect your data while it is in storage. S3 and S3 Glacier use multiple layers of security to protect your data, including physical security, network security, and access controls.

AWS AMI Interview Questions

16. Can you create an AMI from a running instance? If yes, then how?

Yes, you can create an Amazon Machine Image (AMI) from a running Amazon Elastic Compute Cloud (EC2) instance. Here’s how:

1. Sign in to the AWS Management Console and navigate to the EC2 dashboard.
2. Select the instance that you want to create an AMI from.
3. In the Actions menu, select “Image” and then “Create Image”.
4. In the Create Image dialog box, enter a name and description for the AMI.
5. Select the No Reboot option to create the AMI while the instance is running.
6. Click “Create Image” to start the process.

It may take some time for the AMI to be created. When the process is complete, you will see the new AMI in the AMIs tab of the EC2 dashboard. You can use this AMI to launch new EC2 instances that are preconfigured with the same settings and software as the original instance.

Note: If you want to create an AMI from a stopped instance, you can simply stop the instance and follow the same process as above. In this case, you can select the Reboot option if you want the instance to be restarted after the AMI is created.

17. What happens if an instance launched from an AMI stops unexpectedly?

If an instance launched from an Amazon Machine Image (AMI) stops unexpectedly, it will be considered “stopped” and you will not be charged for instance usage. However, any data stored on the instance’s root volume will be lost, as the root volume is deleted when the instance is stopped.

If you have enabled termination protection for the instance, it will not be terminated when it stops. However, you will still need to manually start the instance to be able to use it again.

If you have created an AMI from the instance and enabled auto-recovery for the instance, the instance will be automatically restarted when it stops. This can be useful if the instance stops due to a hardware failure or other issue that is likely to resolve itself after a restart.

It is important to note that auto-recovery is not a replacement for proper instance monitoring and failure handling. You should always have a plan in place to handle instances that stop unexpectedly, including backing up data and creating AMIs as needed.

18. What is the best way to view AMI billing Information related to an account?

The best way to view billing information related to your Amazon Machine Images (AMIs) is to use the AWS Billing and Cost Management dashboard. To access this dashboard:

1. Sign in to the AWS Management Console.
2. In the navigation pane, under the “Account and Billing” heading, click “Billing & Cost Management”.
3. The Billing & Cost Management dashboard will open, displaying an overview of your current billing information, including your current month-to-date charges and any unpaid balances.

You can also use the dashboard to view detailed billing reports, set up billing alerts, and manage your payment methods. To view detailed billing reports, click the “Reports” tab and select the report you want to view. To set up billing alerts, click the “Preferences” tab and click the “Edit” button next to the “Billing alerts” section. To manage your payment methods, click the “Payment Methods” tab.

In addition to the Billing & Cost Management dashboard, you can also view your billing information by downloading your AWS billing reports and examining your monthly invoices. To download your billing reports, click the “Reports” tab and select the report you want to download. To view your monthly invoices, click the “Invoices” tab.

To view billing information specifically related to your AMIs, you can filter the billing reports or invoices by service. For example, you can filter the report by the “Amazon EC2” service to view only charges related to EC2 instances launched from your AMIs.

19. What is the most AMI cost-effective way of running EC2 instances?

Here are some ways to reduce the cost of running Amazon Elastic Compute Cloud (EC2) instances from Amazon Machine Images (AMIs):

1. Use the appropriate instance type: Choose the instance type that best fits your workload. For example, if you are running a batch processing workload, you may be able to use a cheaper instance type with lower CPU and memory requirements.
2. Use reserved instances: If you know that you will be running your instances for an extended period of time, you can purchase reserved instances, which offer a discount compared to on-demand instances.
3. Use spot instances: If you have workloads that can be interrupted, you can use spot instances, which allow you to bid on unused EC2 capacity and can result in significant cost savings.
4. Use auto-scaling: You can use auto-scaling to automatically add or remove instances based on demand, which can help you optimize your EC2 usage and reduce costs.
5. Use Amazon EC2 Auto Scaling to optimize performance and cost: Amazon EC2 Auto Scaling can help you optimize performance and cost by automatically scaling your Amazon EC2 instances in response to changing demand.
6. Use Amazon EC2 Fleet: Amazon EC2 Fleet allows you to specify a combination of on-demand and spot instances and EC2 Auto Scaling will automatically launch, terminate, and scale the instances to meet your target capacity.
7. Use Amazon EC2 Savings Plans: Amazon EC2 Savings Plans offer you discounts on your EC2 usage in exchange for a commitment to a consistent amount of usage (measured in dollars per hour). Savings Plans can be used to reduce the cost of running on-demand and reserved instances, as well as EC2 instances used in Fargate, Lambda, and Batch.

It is important to carefully evaluate your workload requirements and use a combination of these strategies to find the most cost-effective solution for running your EC2 instances from AMIs.

20. What are snapshots? How do you create them?

Amazon Elastic Block Store (EBS) snapshots are point-in-time copies of EBS volumes that are stored in Amazon Simple Storage Service (S3). Snapshots can be used to create new EBS volumes or to restore an existing EBS volume to a previous state.

You can create an EBS snapshot using the AWS Management Console, the AWS command line interface (CLI), or the AWS SDKs. Here’s how to create a snapshot using the AWS Management Console:

1. Sign in to the AWS Management Console and navigate to the Amazon EC2 dashboard.
2. In the navigation pane, under the “Elastic Block Store” heading, click “Volumes”.
3. Select the volume that you want to create a snapshot of.
4. In the Actions menu, select “Create Snapshot”.
5. In the Create Snapshot dialog box, enter a name and description for the snapshot.
6. Click “Create Snapshot” to start the process.

It may take some time for the snapshot to be created. When the process is complete, you will see the new snapshot in the Snapshots tab of the Amazon EC2 dashboard.

Note: If you want to create an Amazon Machine Image (AMI) from an EC2 instance, you can create a snapshot of the instance’s root volume and use it to create the AMI. To do this, stop the instance and follow the steps above to create a snapshot of the root volume. You can then use the snapshot to create an AMI.

21. What does “instance size” mean?

In the context of Amazon Machine Images (AMIs), “instance size” refers to the type and amount of resources (such as CPU, memory, and storage) that are allocated to an Amazon Elastic Compute Cloud (EC2) instance when it is launched from the AMI.

When you launch an EC2 instance from an AMI, you can choose from a variety of instance sizes, each of which offers a different combination of resources. For example, you might choose a small instance with one virtual CPU (vCPU) and 1 GB of memory, or a larger instance with four vCPUs and 16 GB of memory. The instance size that you choose will depend on the workload that you are running and the resources that it requires.

It is important to choose the appropriate instance size for your workload to ensure that the EC2 instance has sufficient resources to run effectively. If you choose an instance size that is too small, the instance may not have enough resources to run your workload efficiently. If you choose an instance size that is too large, you may be paying for resources that you do not need.

In addition to the instance size, you can also specify other instance attributes, such as the instance type (e.g., General Purpose, Compute Optimized, Memory Optimized), the operating system, and the root volume size, when launching an EC2 instance from an AMI.

22. What does “instance store” mean?

In the context of Amazon Machine Images (AMIs), an “instance store” (also known as a “local instance store”) is a temporary block storage device that is physically attached to the host computer that an Amazon Elastic Compute Cloud (EC2) instance is running on.

Instance stores are typically used for temporary storage that is needed during the life of an EC2 instance. They are useful for storing data that changes frequently, such as buffers, caches, and scratch data. However, they are not suitable for storing data that needs to be persisted after the instance is stopped or terminated, as the data is lost when the instance is stopped or terminated.

Instance stores are not the same as Amazon Elastic Block Store (EBS) volumes, which are persistent block storage devices that can be attached to EC2 instances and are stored in Amazon Simple Storage Service (S3). EBS volumes are more suitable for storing data that needs to be persisted after an instance is stopped or terminated.

When you launch an EC2 instance from an AMI, you can specify the number and size of the instance stores that you want to use. The instance stores that you specify will be attached to the instance and will be available for use when the instance is launched. However, it is important to note that instance stores are specific to the host computer that an instance is running on, and are not available if the instance is moved to a different host computer.

23. What is the best way to make sure that all files created by a user on an EC2 instance are deleted after the instance terminates?

There are a few options you can consider to ensure that all files created by a user on an Amazon Elastic Compute Cloud (EC2) instance are deleted when the instance terminates:

1. Use an Amazon Elastic Block Store (EBS) volume as the root device for the instance, and specify the “delete on termination” option when you launch the instance. This will cause the EBS volume to be deleted along with the instance, including any files stored on it.
2. Use an Amazon Elastic File System (EFS) volume to store the user’s files, and specify the “delete on termination” option when you launch the instance. This will cause the EFS volume to be deleted along with the instance, including any files stored on it.
3. Use an Amazon Machine Image (AMI) that is configured to delete the root volume when the instance terminates. This will delete all files stored on the root volume, including those created by the user.
4. Use a script or tool to delete the user’s files when the instance terminates. For example, you could use a termination lifecycle hook in Amazon EC2 Auto Scaling to run a script that deletes the user’s files before the instance is terminated.

It’s also a good idea to regularly back up important data to prevent loss due to instance termination or other failures.

24. How would you go about creating an encrypted copy of an existing unencrypted snapshot so that you don’t need to encrypt future snapshots manually?

To create an encrypted copy of an existing unencrypted snapshot in the Amazon Elastic Block Store (EBS), you can use the following steps:

1. Create a new EBS volume from the unencrypted snapshot using the Amazon Elastic Compute Cloud (EC2) console, the AWS CLI, or the EC2 API.
2. Attach the new EBS volume to an EC2 instance.
3. Use a tool such as dd or cp to copy the data from the unencrypted volume to an encrypted volume. To encrypt the volume, you can use a tool such as cryptsetup or LUKS.
4. Detach the new encrypted EBS volume from the EC2 instance.
5. Create a snapshot of the encrypted EBS volume.
6. Specify the Encrypted flag when creating the snapshot to ensure that all future snapshots created from the volume are also encrypted.

Alternatively, you can use the CopySnapshot API action to create a copy of the snapshot, and specify the Encrypted flag to create an encrypted copy of the snapshot.

It’s important to note that encrypted snapshots can only be used to create encrypted EBS volumes. If you need to create an unencrypted volume from an encrypted snapshot, you will need to create a new snapshot of the encrypted volume and specify the Encrypted flag as false.

25. What do you know about reserved instances? Why should they be used?

Amazon Machine Images (AMIs) are templates that contain the software configuration (operating system, application server, and applications) for an Amazon Elastic Compute Cloud (EC2) instance. Amazon EC2 Reserved Instances are a purchasing option for EC2 instances that allows you to reserve capacity for a one- or three-year term, in exchange for a discounted hourly rate.

There are several benefits to using Amazon EC2 Reserved Instances:

1. Cost savings: With Reserved Instances, you can save up to 75% compared to On-Demand Instance prices.
2. Capacity reservation: Reserved Instances enable you to reserve capacity in a specific Availability Zone, ensuring that you have the capacity you need when you need it.
3. Flexibility: Reserved Instances can be modified or exchanged for other instances, giving you the flexibility to adapt to changing business needs.
4. Simplified billing: With Reserved Instances, you pay an upfront fee and a lower hourly rate, which makes it easier to budget for your EC2 costs.

Overall, Amazon EC2 Reserved Instances are a good choice for businesses that need to run EC2 instances on a predictable, ongoing basis, and want to save money on their EC2 costs.

26. What is the best way to access the console output of an instance in case of an issue?

To access the console output of an Amazon Elastic Compute Cloud (EC2) instance in case of an issue, you can use the following steps:

1. Sign in to the AWS Management Console and navigate to the EC2 dashboard.
2. In the left navigation pane, click on “Instances” under the “Instances” section.
3. Select the instance for which you want to view the console output.
4. In the “Actions” dropdown menu, select “Instance Settings”, and then click on “Get System Log”.

Alternatively, you can use the AWS CLI or the EC2 API to retrieve the console output for an instance.

The console output includes the boot log for the instance, as well as any output generated by the instance’s operating system and applications. It can be useful for troubleshooting issues with the instance or identifying the cause of any errors or problems.

27. Can you give me an example of when you might want to use an Auto Scaling group instead of launching a new instance?

There are several reasons why you might want to use an Amazon Elastic Compute Cloud (Amazon EC2) Auto Scaling group instead of launching a new EC2 instance:

1. Scalability: An Auto Scaling group allows you to automatically add or remove EC2 instances based on demand, so you can scale your application up or down as needed.
2. High availability: An Auto Scaling group can automatically replace any failed or terminated instances, ensuring that your application remains available even if individual instances fail.
3. Cost efficiency: An Auto Scaling group allows you to optimize your Amazon EC2 costs by scaling your instances up or down based on demand, and by using Amazon EC2 Spot Instances to reduce costs further.
4. Ease of use: An Auto Scaling group provides a simple and automated way to manage the size and availability of your EC2 instances, without having to manually launch or terminate instances yourself.

Overall, an Auto Scaling group is a good choice if you need to automatically scale your EC2 instances based on demand, and if you want to ensure high availability and cost efficiency for your application.

One example of when you might want to use an Auto Scaling group is if you are expecting a spike in traffic to your website and you want to be able to scale up quickly to accommodate the increased demand. Another example might be if you have a long-running task that needs to be completed but can be broken up into smaller subtasks that can be completed in parallel, using an Auto Scaling group can help you complete the task more quickly by adding more instances to work on the subtasks simultaneously.

28. What is an AMI and why is it important?

An Amazon Machine Image (AMI) is a pre-configured virtual machine image, which is used to create Amazon Elastic Compute Cloud (EC2) instances. An AMI includes the following:

• A template for the root volume for the instance (for example, an operating system, an application server, and applications).
• Launch permissions that control which AWS accounts can use the AMI to launch instances.
• A block device mapping specifies the volumes to attach to the instance when it’s launched.

AMIs are important because they allow you to quickly and easily launch EC2 instances with a predefined configuration. This can save you time and effort when setting up a new environment, as you don’t need to manually install and configure the operating system and any necessary software. Instead, you can simply launch an instance from an AMI that has the necessary configuration already in place.

You can create your own custom AMIs, or you can choose from a wide selection of pre-built AMIs provided by Amazon or the AWS community. These AMIs can include a variety of operating systems, application servers, and applications, allowing you to choose the AMI that best meets your needs.

29. How do you choose the right AMI for your needs?

There are a few factors to consider when choosing the right AMI for your needs:

Operating system: Choose an AMI with the right operating system for your application. For example, if you are running a Linux-based application, you will want to choose an AMI with a Linux operating system.

Instance type: Choose an AMI that is optimized for the instance type you need. For example, if you need a lot of CPU power, you may want to choose an AMI that is optimized for the C4 instance type.

Region: Choose an AMI that is available in the region where you want to run your instances. This will ensure that you have low latencies and the best performance for your users.

30. How do you optimize the performance of an AMI?

There are a few ways to optimize the performance of an AMI:

Choose the right instance type: Choose an instance type that is optimized for your workload. For example, if you have a CPU-intensive workload, you may want to choose an instance type with a high number of cores and a high clock speed.

Use an optimized AMI: Choose an AMI that is optimized for your workload and instance type. AWS offers a number of optimized AMIs for different types of workloads, such as Amazon Linux 2, Amazon Linux AMI, and Amazon Linux AMI for ARM.

Use caching: Use caching to improve the performance of your AMI by storing frequently accessed data in memory. This can help reduce the number of disk I/O operations and improve the performance of your application.

31. How do you Create a Custom AMI?

To create a custom Amazon Machine Image (AMI), you can follow these steps:

1. Launch an Amazon Elastic Compute Cloud (EC2) instance from an existing AMI that meets your requirements.
2. Connect to the instance and install any additional software or make any configuration changes that you need.
3. Create an AMI from the instance.

Here is a detailed process:

1. Launch an EC2 instance:

• Open the Amazon EC2 console.
• Choose Launch Instance.
• Select an AMI that meets your requirements.
• Choose an instance type and configure any other settings as needed.
• Choose Next: Configure Instance Details.
• Configure the instance details and choose Next: Add Storage.
• Configure the storage options and choose Next: Add Tags.
• Add tags as needed and choose Next: Configure Security Group.
• Configure the security group settings and choose Review and Launch.
• Review the settings and choose Launch.
• Select an existing key pair or create a new key pair, and then choose Launch Instances.

2. Connect to the instance and make any desired changes:

• Connect to the instance using Secure Shell (SSH).
• Install any additional software or make any configuration changes that you need.

3. Create an AMI from the instance:

• Open the Amazon EC2 console.
• In the navigation pane, choose Instances.
• Select the instance that you want to use to create the AMI.
• Choose Actions, and then choose Image, Create Image.
• In the Create Image dialog box, specify the following:
  • A name and description for the AMI.
  • The number of snapshot copies to retain the root device volume. By default, one copy is retained.
• Choose Create Image.

The AMI creation process can take some time to complete, depending on the size of the instance and the number of snapshot copies that you specify. When the AMI is ready, it appears in the AMIs list in the Amazon EC2 console. You can then launch an instance from the AMI.

Note: If you create an AMI from an instance that has multiple volumes attached, the new AMI includes all of the volumes. When you launch an instance from the AMI, the instance is created with all of the volumes in the same Availability Zone as the instance.