2.1.4.2. Application Storage Patterns for Deployments (EFS, S3, EBS)
First Principle: Persistent storage must be managed independently of compute instances to enable immutable deployments, facilitate scaling, and ensure data durability.
When deploying applications, understanding how to manage persistent storage is crucial, especially for stateful applications. Different AWS storage services offer distinct patterns for handling application data during deployments.
Key AWS Storage Services in Deployment Context:
- Amazon Elastic File System (EFS): (A scalable, elastic, cloud-native NFS file system.)
- Pattern: Shared file system. Multiple EC2 instances or containers can access the same data simultaneously. Useful for content management systems or shared configurations. Enables immutable deployments where application code is part of the AMI/container, but shared data resides on EFS.
- Amazon S3 (Simple Storage Service): (An object storage service.)
- Pattern: Object storage. Ideal for static website hosting, storing large files, or as a source for deployment packages. Applications can read/write objects, but it's not a traditional file system.
- Amazon Elastic Block Store (EBS): (Block storage volumes for EC2 instances.)
- Pattern: Instance-attached block storage. Data persists independently of the EC2 instance's lifecycle. Useful for databases or applications requiring high I/O performance. For immutable deployments, data on EBS would be detached from old instances and reattached to new ones, or a new EBS volume would be created from a snapshot.
Key Storage Patterns for Deployments:
- EFS: Shared file access, mutable data, multiple instances.
- S3: Object storage, static assets, deployment artifacts.
- EBS: Block storage, single instance, persistent data.
Scenario: A DevOps team is deploying a containerized application that needs shared access to configuration files and user-uploaded media files across multiple containers. Additionally, the application uses a database that requires high-performance, single-instance block storage.
Reflection Question: How would you design the storage layer for this application, differentiating between the use of Amazon EFS for shared configuration/media and Amazon EBS for the database, to enable immutable deployments and ensure data durability?
Choosing the right storage pattern ensures data integrity and application functionality across deployments.
š” Tip: For truly immutable deployments, strive to make your application stateless. If state is required, externalize it to managed services like Amazon RDS, Amazon DynamoDB, or use shared file systems like Amazon EFS.