CRR from CloudServer to AWS S3 - Workflow

Installation

AWS S3 endpoint (aws-us-east-1 for example) will be defined as a location constraint in the locationConstraint section of CloudServer. The locationConstraint config has properties to set the bucket name, region, credentials for AWS S3.This enables multiple backend feature in CloudServer which Backbeat will leverage to CRR to AWS S3.

replication endpoints will be defined in the config for both Backbeat and CloudServer

env_replication_endpoints:
  site: aws-us-east-1
  type: aws_s3

Operations

CloudServer: PUT Bucket Replication Request

• CloudServer receives the request and checks the Storage Class set in the request

• Check in replicationEndpoints defined in config.json

  • It should match one of the sites
  • If site matches, then it should either have type or servers property
  • If type is aws_s3, CloudServer writes this to the bucket’s replication config property, storageType

CloudServer: PUT object requests on bucket with replication enabled

• CloudServer receives the request and checks if bucket has replication enabled

• If replication is enabled, storageType and storageClass are added to the object’s replicationInfo property and replicationStatus is set to PENDING.

Overview of CRR processing

• Queue Populator populates the metadata entry of the object in Kafka since it has replicationStatus PENDING

• QueueProcessor reads the entry from Kafka and sees that storageType is aws_s3

• QueueProcessor spawns AWSReplicationTask to use the Backbeat routes in CloudServer to put objects in AWS S3

AWS Replication Task

• Upon acquiring an entry to replicate, the task sends a GET Object ?versionId request to CloudServer

• The stream is piped to PUT /_/backbeat Data request with header x-scal-replication-storage-type: aws_s3

• Upon receiving 200, read x-amz-scal-version-id from the header and send PUT /_/backbeat MD request on source to update the properties replicationStatus to COMPLETED, x-amz-scal-version-id to the value received in the header.

CloudServer PUT /_/backbeat Data for AWS route

• If the request has header x-scal-replication-storage-type: aws_s3, use the multipleDataBackend.

• MultipleDataBackend puts in AWS S3 with extra user metadata x-amz-scal-replication-status: REPLICA and stores CloudServer’s versionId for the entry in x-amz-scal-version-id

• If we get 200 from AWS, CloudServer responds back with 200 to Backbeat with x-amz-version-id it received from AWS in the header/body

• Backbeat updates the source object’s metadata to store AWS’ version id and set replication status as COMPLETED