AWS Quick Guide - Amazon S3

Amazon S3

Key Concepts

• Amazon S3 (Simple Storage Service) is an object storage service designed for:

  • Scalability
  • High Availability
  • Durability
  • Security
  • Performance

• Buckets: Containers for storing objects. Each bucket has a globally unique name.

• Objects: Files stored in S3, consisting of data, metadata, and a unique key within the bucket.

• High Availability & Durability: S3 Objects are automatically stored across multiple devices spanning a minimum of three Availability Zones (S3 Standard, S3 Standard-IA, and S3 Glacier).

• Data Protection:

  • Encryption at rest:
    • Server-side encryption with Amazon S3 managed keys (SSE-S3).
    • Server-side encryption with AWS Key Management Service keys (SSE-KMS).
    • Dual-layer (two separate layers of encryption) server-side encryption with AWS Key Management Service keys (DSSE-KMS).
  • Encryption in transit (HTTPS).

• Storage Classes:

  • S3 Standard: Frequently accessed data.
  • S3 Standard-IA: Infrequently accessed data.
  • S3 Intelligent-Tiering: Automatically optimizes cost for infrequent data.
  • S3 One Zone-IA: Infrequently accessed data, stored in single AZ.
  • S3 Glacier Instant Retrieval: Long-term archival data with instant retrieval.
  • S3 Glacier Flexible Retrieval: Long-term archival data with retrieval times in minutes.
  • S3 Glacier Deep Archive: Lowest-cost storage with retrieval times in hours.

• Versioning: Maintains multiple versions of objects to protect against accidental overwrites or deletions.

• Access Control: Managed through Bucket Policies, ACLs, and IAM policies.

• Lifecycle Management: Automates moving objects between storage classes or deletion.

• Cross-Region Replication (CRR): Automatically replicates data across AWS regions for disaster recovery.

• Event Notifications: Triggers actions when specific events occur, like object creation.

• Object Lock: Write-once-read-many (WORM) compliance to prevent object deletion.

• Multipart Upload: Uploads large files in parts for efficiency and reliability.

Amazon S3 Durability and Availability

Durability

• Durability: Sustainability/loss of Data
  • S3 offers high durability of 99.999999999 (or 11 9’s) for objects across multiple Availability Zones.
  • If you store 10,000,000 objects with Amazon S3, you can on average expect to incur a loss of a single object once every 10,000 years.
  • 11 9’s durability across all storage classes.

Availability

• Availability: Accessibility to the Data
  • How readily the service is available?
  • Amazon S3 Standard offers 99.99% availability.
  • In a given year, S3 Standard may not be available for:
    • Yearly: 52m 35s
    • Monthly: 4m 22s
    • Weekly: 1m 0s
    • Daily: 8s
  • Availability varies from one storage class to another.

Amazon S3 Storage Classes:

Amazon Storage Life Cycle Policies:

• A lifecycle policy is a set of rules that define how objects in an S3 bucket should be:
  • Transitioned between different storage classes.
  • Expired or deleted after a certain period.

1. Transitions

• Transitions allow you to automatically move objects between different S3 storage classes as they age.
• This helps optimize storage costs by moving less frequently accessed data to cheaper storage tiers.

2. Expirations

• Expiration rules define when objects should be permanently deleted from the bucket.
• This helps manage data retention and prevents unnecessary storage of outdated files.

Common Use Cases

1. Archiving Old Data

• Move log files or backup data older than 30 days to cheaper storage classes.
• Automatically delete project archives after 7 years.

2. Cost Optimization

• Transition infrequently accessed data to cheaper storage tiers.
• Remove temporary files or older versions of objects.

3. Compliance and Retention

• Automatically delete sensitive documents after a specific retention period.
• Ensure compliance with data retention policies.

• S3 supports waterfall model for transitioning objects between storage classes.

  

Amazon S3 Security

• Identity-Based Policies: Define what actions a user/group/role can perform.
  

  {
          "Version": "2012-10-17",
          "Statement": [
                  {
                          "Effect": "Allow",
                          "Action": [
                                  "s3:GetObject",
                                  "s3:PutObject"
                          ],
                          "Resource": "arn:aws:s3:::venkatesh-bucket/*"
                  }
          ]
  }
  

• Resource-Based Policies: Define who (Principal) can perform actions such as allow or deny.
  

  {
      "Version": "2012-10-17",
      "Statement": [
              {
                      "Sid": "PublicRead",
                      "Effect": "Allow",
                      "Principal": "*",
                      "Action": "s3:GetObject",
                      "Resource": "arn:aws:s3:::venkatesh-bucket/public/*"
              }
      ]
  }
  

• Access Control List (ACL): Fine-grained control over individual objects.

• Block Public Access:

  • Block Public Access is applicable to only Public/Anonymous access.
  • Block public access settings can override ACLs and bucket policies public access.
  • You can apply block public access settings to:
    • Individual buckets or to
    • All buckets in your account.
  • 

• Presigned URLs:

  • Allows you to share objects or allow users to upload objects to buckets without AWS security credentials or permissions.
  • Shared URLs use logged-in user credentials (but in a secure way) to access objects.
  • 

Identity-Based Policies Vs Resource-Based Policies Vs ACLs

Amazon S3 Replication

• Automatic, asynchronous copying of objects across Amazon S3 buckets.
• S3 Objects can be configured to replicate across multiple destination buckets.
• You can change the storage class of replicated S3 objects when performing replication.

• Replication options:

  • Across AWS Regions (CRR).
  • Within the Same AWS Region (SRR).
  • Across AWS accounts.

• Replication configurations are configured at SOURCE bucket.

• Versioning Must be enabled on BOTH source and destination buckets.

• Specify Destination Bucket.

• IAM Role that the S3 bucket should assume to replicate objects.

• You can optionally change destination storage class.

• Replication only supports copying new S3 objects after it is enabled.

  

Amazon S3 Encryption

• Encryption at Rest: Server-side encryption with Amazon S3 managed keys (SSE-S3).
• Encryption in Transit: Server-side encryption with AWS Key Management Service keys (SSE-KMS).
• Dual-layer Encryption: Dual-layer (two separate layers of encryption) server-side encryption with AWS Key Management Service keys (DSSE-KMS).

• Encryption by Default: Server-side encryption is enabled by default for new buckets.

  

Amazon S3 Event Notifications

• You can configure S3 to send notifications when certain events occur, such as object creation, deletion, or modification.

• Object Created: Triggered when an object is created in a bucket.

• Object Deleted: Triggered when an object is deleted from a bucket.

• Object Modified: Triggered when an object is modified in a bucket.

• Destination Includes:

  • SNS: Fan-out messages to systems for parallel processing or directly to people.
  • SQS: Send notifications to an SQS queue to be read by a server.
  • Lambda: Run a Lambda function script based on S3 events.

Amazon S3 Access Points

• AWS S3 Access Points solve the complexity of managing bucket policies for multiple teams and applications by creating separate access points with individualized policies for each team or use case.
• Traditional S3 bucket policies become difficult to manage as more teams and applications are added, leading to complex, hard-to-audit policies with limited size and flexibility.
• Create a separate S3 access point for every user or application that needs access to S3 bucket.
• You can use access points to control access to buckets, objects (folders), or both.

• With S3 Access Points, organizations can create multiple access points for a single bucket, each with its own unique properties:

  • Unique S3 URI
  • Specific Access Point ARN
  • Customizable access policy
  • Network origin control (internet or VPC-specific)

• Access Points allow granular folder-level access control, enabling different teams to access specific folders within the same S3 bucket while maintaining strict access boundaries.

• Network origin features let you restrict access points to specific VPCs or make them publicly accessible, providing enhanced security and network segmentation.

• To use Access Points effectively, both the Access Point policy and the underlying bucket policy must permit the requested action, with a recommended bucket policy that delegates access control to the Access Points.

• Deny policies can be implemented at both the Access Point and bucket levels to provide additional security, such as preventing object deletion in specific folders or restricting direct bucket access.

Amazon S3 Access Points Best Practices:

• Granting minimal necessary permissions.
• Using Access Point ARNs in IAM policies.
• Delegating access control to Access Points through bucket policies.
• Leveraging Access Points for scalable and manageable S3 access control.

Amazon S3 Multi-Region Access Points

• Multi-region Access Points enable you to create a single access point that spans multiple AWS Regions, providing a unified view of data across all Regions.
• Multi-region Access Points are useful for cross-Region replication and cross-Region data access.
• With Multi-region Access Points, you can access data across multiple AWS Regions using a single URL, ensuring data consistency and reducing the risk of data loss or corruption.

References

• Amazon S3
• Amazon S3 Access Points
• Amazon S3 Replication
• Amazon S3 Encryption
• Amazon S3 Event Notifications
• Amazon S3 Access Points Best Practices