하위 도메인으로 리디렉션한다는 사실은 별 문제가 아니며 "경로를 기반으로"는 S3의 라우팅 규칙을 리디렉션하는 방법과 거의 같습니다.
<RoutingRules>
<!-- example.com/blog -->
<RoutingRule>
<Condition>
<!-- no/goes here -->
<KeyEquals>blog</KeyEquals>
</Condition>
<Redirect>
<ReplaceKeyWith/> <!-- nothing -->
<Protocol>http</Protocol>
<HostName>blog.example.com</HostName>
</Redirect>
</RoutingRule>
<!-- example.com/blog/* -->
<RoutingRule>
<Condition>
<!-- note the/is after, not before, blog -->
<KeyPrefixEquals>blog/</KeyPrefixEquals>
</Condition>
<Redirect>
<ReplaceKeyPrefixWith/> <!-- nothing -->
<Protocol>http</Protocol>
<HostName>blog.example.com</HostName>
</Redirect>
</RoutingRule>
</RoutingRules>
http://docs.aws.amazon.com/AmazonS3/latest/dev/HowDoIWebsiteConfiguration.html#configure-bucket-as-website-routing-rule-syntax