TellerHttpCaching

HTTP Caching In Teller

Introduction

Glance consists of two services, Parallax, the image registry, which stores image metadata describing the image and where to fetch it, and Teller which acts as a proxy for the object store containing the actual image data. Both Parallax and Teller are HTTP servers and therefore can benefit from the performance improvements offered by HTTP caching. The following is a proposal for how to add HTTP caching to the Glance project, and in particular the Teller sub-project (for Parallax see ParallaxHttpCaching).

It should be noted that HTTP caching is not the only type of caching that could improve the speed of OpenStack builds. Down the road, we leave open an option for adding memcached to Parallax, a Bit-Torrent distribution system within the cluster and any number of other options. We are starting with HTTP caching first since it will offer a dramatic savings in bandwidth and performance without a lot of work and at the same time as a clear implementation path dictated by RFC 2616.

Background on HTTP Caching