Why Http Server in SOA or ESB High Aavailability setup?

Question

I was trying to come up with a design for high availability for our SOA setup and stumbled upon the this link http://docs.oracle.com/cd/E17904_01/core.1111/e10106/ha_soa.htm#CHDHJIED

The documents suggests placing a HTTP server on top of a clustered environment behind a Load balancer.

I could not understand what value add does an HTTP server bring to a SOA or OSB setup as we do not host a website which would have some static content like images, html pages etc.

I might be ignorant about the aspects of its usage, would appreciate if someone from the forum can help me understand this.

Thanks,

Wajid

Answer 1

The main benefit of putting HTTP server is the ability to use URL routing.

See, when system matures it rarely ends with a closed set of services. They usually expand, different technologies come into use for different parts of APIs as the time goes.

URL routing allows to cover this up, routing legacy APIs to older services and newer APIs to new services.

Another important usage of HTTP server is DDoS mitigation. Usually it has more power when it comes to collecting access statistics and applying black lists.

SOA without HTTP server is not elastic and potentially vulnerable. Hence the general recommendation to put HTTP server first.