1. A method for executing a target program, comprising: opening, in response to a request, a door between the source container and the global container, wherein the source container is controlled by the global container and the request specifies a target program; sending the request to an access module located in the global container using the door; verifying that the request can be executed in a target container using a policy definition, wherein the target program is in the target container and wherein the target container is controlled by the global container; logging in to the target container after the request has been verified; initiating a gateway within the target container in response to the login; setting an execution context of the gateway based on the policy definition; and executing the target program by the gateway, using the execution context, to generate a response to the request.