The emergence and consolidation of container-based virtualization techniques has simplified and accelerated the development, provisioning, and deployment of applications for the Cloud. When considering the case of composite service-based applications that rely on service middleware solutions for their operation, container-based virtualization offers the opportunity for rapid and efficient building and deployment of lightweight, optimally configured middleware instances. As such, it provides an ideal tool for the purposes of cloudifying existing middleware solutions and offering them as part of larger PaaS offerings. As part of this effort, our investigation focuses on leveraging and evaluating a container-based virtualization environment towards enabling the assembly, provisioning, and execution of dynamically tailored instances to satisfy service middleware communication requirements of specific applications. For these purposes we scope the discussion on one particular type of messaging middleware for composite service applications, the Enterprise Service Bus (ESB) technology.