# A Survey on Modeling Languages for Applications Hosted on Cloud-Edge Computing Environments
## 3 Results
### Description of the Deployment Phase
It aims to create a versatile application topology language for describing cloud applications and making it easier to convert from languages like TOSCA or Blueprints into a single model. GENTL might use TOSCA or similar CMLs for the deployment phase. Additionally, it could include Blueprints [26] to help developers make abstract descriptions of cloud service offerings and deployment. It is important to note that a language like GENTL can handle deployment for various deployment units. Researchers have made efforts to enhance existing modeling languages, aside from TOSCA, or even develop custom ones that incorporate additional descriptions relevant to the deployment phase. In their work, [PERSON] et al. [23] presented MoDMaCAO as an extension that improves the capabilities of the OCCI Platform. The OCCI Platform, which is itself an extension of OCCI, gains enhanced functionality through MoDMaCAO's inclusion of additional lifecycle descriptions. This extension simplifies the process of deploying and managing applications and components on IaaS resources, particularly for platforms that adhere to the OCCI standard. The OCCI Platform provides entities that enable the clear description of application components and their relationships. The authors also established a connection between the OCCI Infrastructure and the OCCI Platform to accurately represent the underlying infrastructure. Consequently, they established a connection between the two components to ensure a comprehensive representation of both the application components and the associated infrastructure. In the BEACON project, a HOT extension [27] is utilized to describe the deployment which is distributed across the continuum through an orchestrator broker. Another example is the UML (Unified Modeling Language) extension proposed in [28], which can describe the deployment of virtual machines using the specification level deployment diagram and instance level deployment diagram. Additionally, it extends the UML class diagram to describe services. [PERSON] et al. [21] presented a domain-specific language designed specifically for container deployment in Fog environments. [PERSON] et al. [29] recommended using a custom XML syntax to describe the orchestration of containers on Docker Swarm. This language needs to be translated by a reasoner to generate a Docker Swarm deployment plan. Certain TOSCA extensions deviate from the conventional TOSCA semantics and introduce their own descriptive elements. One such extension is Tosker [16], which enables the depiction of containers using new custom entities. Another extension, TOSCA Light, introduced by [PERSON] et al. [30], defines custom entities by specifying the set of EDMM compliance rules for TOSCA-based models. The deployment phase in TOSCA Light can be described using the topology template, similar to traditional TOSCA. Furthermore, a set of TOSCA extensions was introduced by [PERSON] et al. [20] to describe applications at both the design time level and instance level. The suggested syntax achieves a new way, distinct from TOSCA, of expressing constraints, requirements, and criteria that are independent from the underlying hosting infrastructure (hybrid clouds, multi-clouds, edge-based platforms and FaaS-based applications).