Subdomain from different S3 bucket on same cloudfront distribution

Firstly, the point of Cloudfront is to serve cached content - if you try to serve uncached content from Cloudfront it is slower than serving it directly from S3, in almost all cases (something like streaming content would be the exception). Consider for a moment what needs to happen to serve content from Cloudfront - it needs to be retrieved from the origin server to a location that is geographically close to the user - which means that for a request where Cloudfront has to retrieve content from the origin server, you add extra latency into the request, and the user receives content slower. It is only once the content is available at the edge location that subsequent requests are faster.

The best approach to this problem is to change your filenames when you update a page - this will force Cloudfront to retrieve the new content. Again, keep in mind that Cloudfront is typically used for media files (including images) and style/javascript - and not so much for html. Esssentially, you would have your HTML on S3, and your images on Cloudfront - with any changes you make, you can change the name of the file on Cloudfront (e.g. file-v1.jpg, file-v2.jpg, etc). Another common way is including a query string with version information.

Also, keep in mind that Cloudfront does not serve gzipped content - which may result in a slower response than from a regular server (although, in your case, S3 doesn't identify gzip capable browsers either).

Finally, if you want to, you can use invalidation to force Cloudfront to discard its existing copy and fetch a new one from the origin server. Note, however, that Cloudfront gives you only 1000 free invalidations per month, after which the cost is $0.005/invalidation.

The lowest time Cloudfront will keep content is 1hr, although, the default is 24hr. I'd therefore try to set the max-age to at least 3600. Consider also an s-maxage header (for shared - i.e. proxied content). Amazon recommends this caching tutorial.

There was a recent problem with this, rectified a few days ago

Two Cloudfront Distributions

Since AWS allows for overlap between wildcard alternate CNAMEs in the same AWS account, you can switch between two cloudfront distributions in the following manner:

• Use www.domain.com as Alternate CNAME for Prod distribution 1
• Use *.domain.com as Alternate CNAME for Prod distribution 2
• Point your CNAME DNS www.domain.com to distribution 1 or distribution 2. (*.cloudfront.net).
• Remove the alternate CNAME from the distribution which you don't want to serve the content from anymore.

However, the two different distribution DNSs (*.cloudfront.net) may point to the same edge nodes, which means that the way your content is served is by matching the cloudfront.net CNAME to the Edge nodes serving it and then to match by hostname. In this case, if both your distributions are using the same edge nodes (it can be checked for example with dig) the cut will not be clean.

e.g. If both distributions share one or more edge nodes, distribution 1 with Alt CNAME www.domain.com will take precedence over distribution 2 with the more generic *.domain.com until the CNAME gets removed from the distribution 1 config in all edge nodes. So the version retrieved from one request may be different from the other during the transition period.