We are using CloudFront for our static assets but also wanted to allow for Gzip. We set up a new distribution with a custom origin pointing back to our application servers which are behind a elastic load balancer. We manually keep the files in sync across the cluster and update them when we publish.
However, with this set up, we get nothing but Miss and RefreshHits from CloudFront, which so far has defeated the purpose. Is there any additional settings in order to use an ELB as your custom origin? In the docs, it references this as a viable solution.
It appears when we point the distribution to a single server in our production cluster, cloudfront properly caches our assets.
Is it possible that the sticky sessions cookie and the subsequent header that gets added by it could be an issue?
Cache-Control: no-cache="set-cookie" //Added by load balancer
Any ideas?
FYI – currently, we have our custom origin pointing to a single EC2 instance, so caching is working correctly – in case you try to curl the file below.
Example headers:
curl -I http://static.quick-cdn.com/css/9850999.css
HTTP/1.0 200 OK
Accept-Ranges: bytes
Cache-Control: max-age=3700
Cache-Control: no-cache="set-cookie"
Content-Length: 23038
Content-Type: text/css
Date: Thu, 12 Apr 2012 23:03:52 GMT
Last-Modified: Thu, 12 Apr 2012 23:00:14 GMT
Server: Apache/2.2.17 (Ubuntu)
Vary: Accept-Encoding
X-Cache: RefreshHit from cloudfront
X-Amz-Cf-Id: K_q7Zy3_jdzlEJ85ukELVtdx1GmuXqApAbZZ7G0fPt0mxRMqPKX5pQ==,RzJmPku-rEIO9WlvuSoKa8hiAaR3dLk5KC4cQMWWrf_MDhmjWe8n6A==
Via: 1.0 28c34f9fbf559a21ee16594849e4fc9c.cloudfront.net (CloudFront)
Connection: close
Best Answer
It's possible that CloudFront doesn't handle multiple headers with the same name correctly and isn't seeing your
max-agedirective. According to this CloudFront does use theExpiresheader if present, so try getting your origin server to set that instead (preferably relative to the request time). For Apache I think you want something like this with mod_expires: