iCompaas Support

Profile Applicability:

• Level 2

Description:
Cross-Region Replication (CRR) is an Amazon S3 feature that automatically replicates objects from one S3 bucket to another bucket in a different AWS region. Enabling CRR ensures that the data in your S3 buckets is replicated across different regions, providing higher availability, data durability, and disaster recovery capabilities. It can also help meet compliance and regulatory requirements for data storage in multiple geographic locations.

Rationale:
Enabling CRR ensures that critical data is replicated across multiple AWS regions, enhancing fault tolerance and improving the overall durability of data stored in S3. This is particularly important for applications that require high availability and data redundancy, as well as those that need to comply with geographical data residency requirements.

Impact:
 Pros:

• Provides higher data availability and durability by replicating data across different AWS regions.

• Improves disaster recovery capabilities by ensuring data is stored in multiple locations.

• Helps meet compliance requirements by storing data in specific geographic regions.

• Increases fault tolerance and reduces the risk of data loss due to regional failures or outages.

Cons:

• May incur additional costs for data transfer and storage in multiple regions.

• Can introduce complexity in managing replication rules and configurations.

• May have slight latency when replicating data between regions, depending on the geographic distance.

Default Value:
By default, S3 buckets do not have cross-region replication enabled. It needs to be explicitly configured and requires the creation of a replication rule and a destination bucket in a different region.

Pre-requisites:

• AWS IAM permissions to manage S3 replication configuration:
   s3:PutBucketReplication
   s3:GetBucketReplication

• Both source and destination S3 buckets must have versioning enabled.

• Access to both source and destination buckets, as well as the relevant permissions to configure replication.

Remediation:

Test Plan:

Using AWS Console:

1. Sign in to the AWS Management Console.

2. Navigate to S3 and select Buckets from the left-hand menu.

3. Select the S3 bucket you want to check for CRR.

4. Under the Management tab, scroll down to the Replication section.

5. Check if Cross-Region Replication is enabled and verify the replication configuration:

   • Ensure that the source bucket has a replication rule configured with a destination bucket in a different region.

   • Verify the replication rule includes the necessary filters, such as replication for all objects or specific prefixes/tags.

6. If CRR is not enabled, click Add rule to create a new cross-region replication rule.

Using AWS CLI:

1. List all S3 buckets:
   

   aws s3api list-buckets --query "Buckets[*].Name"

2. For each bucket, check if Cross-Region Replication is configured:
   

   aws s3api get-bucket-replication --bucket <BUCKET_NAME>

3.  If the output shows the replication configuration, verify that the destination bucket is in a different region.
   

4. If CRR is not enabled, create a replication configuration by running the following command:
   

   aws s3api put-bucket-replication --bucket <BUCKET_NAME> --replication-configuration file://replication_config.json

5. Example 

replication_config.json:
{

  "Role": "arn:aws:iam::<ACCOUNT_ID>:role/<IAM_ROLE>",
  "Rules": [
    {
      "ID": "ReplicateAllObjects",
      "Status": "Enabled",
      "Prefix": "",
      "Destination": {
        "Bucket": "arn:aws:s3:::<DESTINATION_BUCKET_NAME>",
        "StorageClass": "STANDARD"
      }
    }
  ]
}

6. Verify that the replication configuration is set correctly:
   

   aws s3api get-bucket-replication --bucket <BUCKET_NAME>

Implementation Plan:

Using AWS Console:

1. Open the S3 Console and select the bucket you want to configure replication for.

2. Under the Management tab, click Replication and then Add rule.

3. Choose Cross-Region Replication and select a destination bucket in a different region.

4. Enable versioning if it is not already enabled on both the source and destination buckets.

5. Set the desired replication rule filters (e.g., all objects or specific prefixes/tags) and apply the configuration.

6. Save the replication rule and verify that the objects are being replicated as per the rule.

Using AWS CLI:

1. To enable cross-region replication, create a replication rule using the following command:
   

   aws s3api put-bucket-replication --bucket <BUCKET_NAME> --replication-configuration file://replication_config.json

2. Verify the replication configuration:
   

   aws s3api get-bucket-replication --bucket <BUCKET_NAME>

Backout Plan:

Using AWS Console:

1. If enabling CRR causes issues, sign in to the AWS Management Console.

2. Navigate to Amazon S3, select the bucket, and go to the Management tab.

3. In the Replication section, disable the replication rule or delete the configuration.

4. Save the changes and monitor the bucket to ensure that replication is no longer applied.

Using AWS CLI:

1. To disable Cross-Region Replication, run:
   

   aws s3api delete-bucket-replication --bucket <BUCKET_NAME>

2. Verify that replication has been removed:
   

   aws s3api get-bucket-replication --bucket <BUCKET_NAME>

Reference:

• Amazon S3: Cross-Region Replication

• AWS CLI: get-bucket-replication

• AWS CLI: put-bucket-replication

• AWS CLI: delete-bucket-replication

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