About CloudFront
Table of Contents
Table of Contents
What is Amazon CloudFront?
Amazon CloudFront is a global, content distribution network for delivering content stored in your S3 buckets. It's an additional service that's offered by Amazon that you must sign-up for in order to use. CF distributions provide an efficient way of delivering key content to end users all over the world by using a global network of "edge locations." An edge location is a geographical site where CloudFront caches copies of commonly downloaded objects such as web pages, images, media files, etc. Since EC2 instances are region-specific, delivering content with low latencies around the world can be difficult. In order to provide faster download times for your global userbase, set up CloudFront distributions for commonly downloaded assets.
An origin server for CloudFront is an S3 bucket that contains the original version ("master copy") of an object. When a user requests one of the objects in your CF distribution, CloudFront determines which edge location is best able to serve the content for future requests. Although normal latencies are expected for the first request, subsequent requests will be downloaded much faster because a copy of the object will remain cached at the edge location until the object's TTL expires. (default = 1hr)
There are two types of CF distributions that you can create:
- basic - ideal for serving commonly used static content
- streaming - ideal of serving commonly downloaded media files
You can set up a CloudFront distribution to serve both public and private content. See Serving Private Content.
Before you can create a distribution, you must first sign-up for the Amazon's CloudFront service. Be sure to review their detailed pricing information.
To learn more, check out our blog post: Amazon releases CloudFront: a cloud content distribution network or see Amazon CloudFront or the Getting Started Guide.
Things to Consider
- CloudFront is very particular about S3 bucket names. You may need to create a new S3 bucket that has a compatible bucket name. See the "S3 Bucket Names for CloudFront" section below.
- You can create multiple distributions that reference the same S3 bucket.
- Only objects that have "public-read" access will be available for distribution.
- 'https' links are not supported
- If you are using a CNAME, you must first be sure to register that domain with your DNS provider. It must also be a unique name that's unused. For example, you cannot use "mysite.com" as a CNAME. You must create a new subdomain (ex: assets.mysite.com).
- You can specify up to 10 CNAMEs per distribution.
- CloudFront is not AWS-region specific.
- You can have up to 100 CF distributions
- If you overwrite an existing object in a distribution, Cloudfront will not push the new version of the object to an edge location until the object's TTL has been expired and an end user makes a request for the object at that edge location.
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