Cloud systems allow to run parallel applications using solutions with distributed heterogeneous architecture. Software development for heterogeneous distributed environment requires a module-based design. The components in such module system are connected by means of telecommunications network enabling message passing. This article describes an interaction model for components in distributed applications. The model was designed based on the paradigm of Variable Speed Hybrid Petri Nets and allows to analyse system performance at various tiers: selection of the optimum approach to load balancing between components; making scaling decisions to enhance performance of certain modules; fine-tuning the interaction between system components. The model is not contingent on particular tools a user might employ to implement a solution; it also provides a monitoring data integration functionality.

The model contains descriptions of standard messaging patterns linking components of distributed applications. These patterns include request-reply and publish-subscribe. Load balancing algorithms for various schemes of these patterns usage have been developed for a cloud environment.