Method and system for providing on-demand content delivery for an origin server
An infrastructure “insurance” mechanism enables a Web site to fail over to a content delivery network (CDN) upon a given occurrence at the site. Upon such occurrence, at least some portion of the site's content is served preferentially from the CDN so that end users that desire the content can still get it, even if the content is not then available from the origin site. In operation, content requests are serviced from the site in the usual manner, e.g., by resolving DNS queries to the site's IP address, until detection of the given occurrence. Thereafter, DNS queries are managed by a CDN dynamic DNS-based request routing mechanism so that such queries are resolved to optimal CDN edge servers. After the event that caused the occurrence has passed, control of the site's DNS may be returned from the CDN back to the origin server's DNS mechanism.
1. A method associated with an origin server that has a content provider domain mirrored at a set of mirror sites, comprising:
having a content delivery network (CDN) service provider provide a traffic management service to the origin server to determine which of the set of mirror sites should receive a request to the content provider domain that is replicated at the set of mirror sites, wherein the traffic management service is provided by aliasing the content provider domain to a traffic management domain managed by the CDN service provider;
as the traffic management service is being provided, monitoring the origin server for occurrence of a given condition, wherein the given condition is one of: a failure at the origin server, an occurrence of excess demand at a Web site hosted on the origin server, a receipt of a request for content that cannot then be served from the origin server, an occurrence of excess traffic to the Web site originating from a given geography or network, an occurrence of excess latency at the Web site as measured by network agents, and a denial of service attack;
upon occurrence of the given condition, dynamically rewriting a DNS record to point to a content delivery network (CDN) domain that is distinct from a content provider domain and the traffic management domain used by the CDN service provider to provide the traffic management service; and
as the given condition persists, having a domain name server in the content delivery network (CDN) resolve the content delivery network domain to identify a content server for use in servicing the request.
2. The method as described in claim 1 wherein the origin server normally hosts given content associated with the content provider domain, wherein the given content is an object, or a markup language page having a set of one or more embedded objects.
3. The method as described in claim 1 wherein the DNS record is rewritten using a CNAME.
4. The method as described in claim 1 further including:
upon termination of the given condition, dynamically rewriting the DNS record to once again point to the traffic management domain used by the CDN service provider to provide the traffic management service.