What is an AWS AMI?
An Amazon Machine Image (AMI) is a pre-configured template used to create a virtual machine within AWS. Think of an AMI as a blueprint for your cloud instances, containing the operating system, application server, and applications needed to run your workload. AMIs provide the essential information required to launch an instance, including: Root Volume Template: Contains the operating system, application server, and applications. Launch Permissions: Dictates which AWS accounts can use the AMI to launch instances. Block Device Mapping: Specifies the volumes to attach to the instance when it is launched. Why AMIs ? Consistency and Standardization AMIs ensure that every instance launched from the same image has an identical configuration, reducing inconsistencies and configuration drift. This is crucial for maintaining a standardized environment across development, testing, and production. Efficiency and Speed By using AMIs, you can quickly spin up new instances with a predefined configuration, saving time compared to manually setting up servers. This is especially beneficial for scaling applications or recovering from failures. Security and Compliance AMIs can be tailored to meet specific security and compliance requirements. For example, using CIS-hardened images ensures your instances comply with the Center for Internet Security (CIS) benchmarks, providing a robust security posture. Simplified Management With AMIs, managing software updates and patches becomes more straightforward. You can update the AMI and deploy new instances from the updated image, ensuring all instances are running the latest software versions. To demonstrate the power and flexibility of AMIs, we will create a custom Ubuntu CIS- hardened AMI configured with NGINX as a web server and Docker for running containerized applications.
