AWS AMI (Amazon Machine Image)

An Amazon Machine Image (AMI) is a pre-configured virtual machine image, provided by AWS, that you can use to launch instances in the Amazon Elastic Compute Cloud (EC2). It contains the necessary information to launch an instance, including the operating system, application server, and application software.

Here are some key features of AMIs:

• Operating system: AMIs can be based on popular operating systems such as Windows, Linux, and Ubuntu.
• Application server: AMIs can be configured with popular application servers such as Apache, IIS, and Tomcat.
• Application software: AMIs can be configured with popular application software such as databases, big data platforms, and developer tools.
• Customizable: You can create custom AMIs by starting with an existing AMI and adding or removing software as needed.
• Shared: AMIs can be shared with other AWS accounts, making it easy for teams to collaborate on projects.
• Versioning: AMIs can be versioned, allowing you to roll back to a previous version if needed.
• Marketplace: AWS Marketplace provides a wide selection of AMIs from AWS and third-party vendors, making it easy to find the right AMI for your application.

In summary, AWS AMI is a pre-configured virtual machine image that can be used to launch instances in EC2. It contains the operating system, application server, and application software that are needed for the instance to run. It is customizable, can be shared with other AWS accounts, versioned, and there is a marketplace that provides a wide selection of AMIs from AWS and third-party vendors.

AWS AMI Lifecycle

The lifecycle of an Amazon Machine Image (AMI) in AWS includes several stages, starting with the creation of the image, and ending with its retirement or deletion. Here’s a brief overview of the AMI lifecycle:

1. Creation: An AMI is created by taking a snapshot of an existing EC2 instance, or by importing an image from another source.
2. Availability: Once an AMI is created, it can be used to launch new instances. Users can launch instances from the image by specifying the image ID in the launch request.
3. Modification: Users can make changes to an existing AMI by creating a copy of the image and modifying the copy. The original image remains unchanged.
4. Versioning: Users can create new versions of an AMI by creating a new image and specifying a new version number. This allows users to roll back to a previous version if needed.
5. Deprecation: AWS may deprecate an AMI when it’s no longer supported, or when it’s replaced by a newer version. Deprecated AMIs are still available for use, but AWS may not provide support or security updates for them.
6. Retirement: Users can retire an AMI when it’s no longer needed. Retired AMIs are still available for use, but are not visible in the management console or the command line interface (CLI).
7. Deletion: Users can delete an AMI when it’s no longer needed. Deleted AMIs cannot be recovered.

Overall, the lifecycle of an AMI in AWS includes several stages, starting with the creation of the image, and ending with its retirement or deletion. Users can make changes to the images, create new versions, and eventually deprecate, retire or delete an AMI when it’s no longer needed.

AWS AMI Types

There are several types of Amazon Machine Images (AMIs) available in AWS, each with its own set of features and use cases:

1. EBS-backed AMIs: These AMIs are based on Amazon Elastic Block Store (EBS) volumes, which provide persistent storage for instances launched from the image. EBS-backed AMIs are well-suited for use cases that require a consistent and reliable storage option, such as databases or file servers.
2. Instance Store-backed AMIs: These AMIs are based on instance store volumes, which are temporary storage options that are associated with the host instance. Instance store-backed AMIs are well-suited for use cases that require temporary storage or for applications that can tolerate data loss in the event of an instance failure.
3. Windows AMIs: These AMIs are based on the Windows operating system and can be either EBS-backed or instance store-backed. Windows AMIs are well-suited for use cases that require a Windows operating system, such as running Microsoft applications.
4. Shared AMIs: These AMIs can be shared across multiple AWS accounts, making it easy for teams to collaborate on projects. Shared AMIs can be either EBS-backed or instance store-backed.
5. Marketplace AMIs: These AMIs are available on the AWS Marketplace and can be used to launch instances with pre-installed software. Marketplace AMIs can be either EBS-backed or instance store-backed.

In summary, there are several types of AMIs available in AWS, including EBS-backed, Instance Store-backed, Windows, Shared and Marketplace AMIs. Each type has its own set of features and use cases, and users can choose the one that best fits their needs.

Why EBS backed instance is more popular than Instance Store backed instance?

EBS-backed instances are more popular than instance store-backed instances for a few reasons:

1. Persistent storage: EBS-backed instances provide persistent storage for instances launched from the image, whereas instance store-backed instances only provide temporary storage that’s associated with the host instance. This means that data stored on an EBS volume will persist even if the instance is terminated, whereas data stored on an instance store volume will be lost.
2. Flexibility: EBS volumes can be easily detached from one instance and attached to another, allowing users to move data between instances or across Availability Zones. Instance store volumes, on the other hand, are physically attached to the host instance and cannot be detached.
3. Snapshots: EBS volumes can be easily snapshotted, allowing users to create point-in-time backups of their data. Snapshots can be used to create new EBS volumes or to restore data to existing volumes. Instance store volumes cannot be snapshotted.
4. Performance: EBS-optimized instances can deliver improved performance for EBS volumes. These instances have dedicated bandwidth to EBS and can deliver improved performance for I/O-intensive workloads.
5. Scalability: EBS volumes can be increased or decreased in size as needed, which is useful for applications that require more storage over time. Instance store volumes have a fixed size and cannot be increased or decreased.

In summary, EBS-backed instances are more popular than instance store-backed instances because they provide persistent storage, flexibility, snapshots, scalability and improved performance, which makes them better suited for most production workloads.

 

Differences between instance store-backed instances and EBS-backed instances in AWS:

There are several key differences between instance store-backed instances and EBS-backed instances in AWS:

1. Storage: Instance store-backed instances use storage that is physically attached to the host instance, known as instance store volumes. These volumes provide temporary storage that is associated with the host instance. EBS-backed instances, on the other hand, use storage that is based on Amazon Elastic Block Store (EBS) volumes. These volumes provide persistent storage that can be detached and attached to other instances, or even across availability zones.
2. Data persistence: Data stored on instance store volumes will be lost if the instance is terminated, whereas data stored on EBS volumes will persist even if the instance is terminated.
3. Snapshots: EBS volumes can be easily snapshotted, allowing users to create point-in-time backups of their data. Snapshots can be used to create new EBS volumes or to restore data to existing volumes. Instance store volumes cannot be snapshotted.
4. Flexibility: EBS volumes can be easily detached from one instance and attached to another, allowing users to move data between instances or across Availability Zones. Instance store volumes, on the other hand, are physically attached to the host instance and cannot be detached.
5. Scalability: EBS volumes can be increased or decreased in size as needed, which is useful for applications that require more storage over time. Instance store volumes have a fixed size and cannot be increased or decreased.
6. Performance: EBS-optimized instances can deliver improved performance for EBS volumes. These instances have dedicated bandwidth to EBS and can deliver improved performance for I/O-intensive workloads.

In summary, instance store-backed instances are best suited for use cases that require temporary storage or for applications that can tolerate data loss in the event of an instance failure. On the other hand, EBS-backed instances are well-suited for use cases that require a consistent and reliable storage option, such as databases or file servers, as they provide persistent storage, snapshots, flexibility, scalability, and improved performance.