Abstract: Embodiments govern cloud environments using a policy engine. A plurality of policy definitions for governing a plurality of managed environments can be received at a policy engine, each policy definition including one or more conditions and one or more actions, where the managed environments implement cloud based virtual machines that host cloud based applications. Events that relate to one or more of the managed environments can be received at the policy engine. Conditions for the policy definitions can be evaluated by the policy engine, where conditions for a first policy definition are triggered based on one or more of the received events. Based on the evaluating, one or more actions of the first policy definition can be performed, the one or more actions changing a first managed environment that is governed by the first policy definition.

Abstract: A web server provided according to aspect of the present disclosure maintains registration data indicating the browsers to be notified upon occurrence of corresponding events. Upon receiving notification of occurrence of an event from an application server, the web server determines the set of browsers registered to receive notification of the occurrence of the event, and pushes the event to each of the set of browsers. By relying on a web server for such operation, each of the applications in the application server can be implemented as stateless applications, thereby providing advantages such as scalability and portability.

Abstract: A web server provided according to aspect of the present disclosure maintains registration data indicating the browsers to be notified upon occurrence of corresponding events. Upon receiving notification of occurrence of an event from an application server, the web server determines the set of browsers registered to receive notification of the occurrence of the event, and pushes the event to each of the set of browsers. By relying on a web server for such operation, each of the applications in the application server can be implemented as stateless applications, thereby providing advantages such as scalability and portability.