The use of virtualization technologies is one of major trends in computer networks. Up to now, most of monitoring tasks on Virtual Nodes, made up of several system virtualization environments and network virtualization environments, require manual intervention via non-standardized interfaces. Although monitoring based on proprietary command lines and graphical user interfaces may be enough for homogeneous Virtual Nodes, it is certainly not suitable for monitoring, in an integrated way, Virtual Nodes in which, the aforementioned environments use heterogeneous virtualization technologies, both in networks and systems. In this paper, we demonstrate that the mashup technology can be used to carry out the integrated monitoring of heterogeneous Virtual Nodes. In this sense, we present a mashup-based architecture targeted to monitor such type of Virtual Nodes, we introduce a reference implementation of the mashup-based architecture, and we develop on it, three monitoring mashups. The quantitative assessment of these mashups corroborates that they generate low traffic and have short response time. Furthermore, their qualitative assessment reveals that it is feasible to provide flexible and extensible mashups for monitoring Virtual Nodes.