## 1 Introduction  
The World Economic Forum (WEF) has a vision to shape a sustainable and reliable digital future, and the Internet of Things (IoT) is considered to be one of largest enablers for sustainable digital transformation [1]. In recent years, there has been a shift from physical space to cyberspace [2], with the sole aim to interconnect every physical thing to form a network of things (the IoT) [3; 4; 5]. The various enabling technologies proposed commonly include Quick Response (QR) codes,and Radio Frequency Identification (RFID) for the identification of things. Moreover, wireless sensor networks and related networking technologies are exploited to interconnect these smart objects to form an IoT space. The main motivation of the IoT is to enhance business processes concerning efficiency and costs in enterprise systems [6; 7; 8; 9; 10]. Every physical object, in such a smart space, which connects to the IoT is called an edge node which senses ambient scenarios and bridges the gap between the real world and networks [11]. The massive number of links enables the interaction between edge nodes in such IoT-empowered smart spaces. One of the recent advancements in the field of IoT are mission-critical Internet of Things (MC-IoT) applications. In MC-IoT, operations are performed in real-time by physical nodes and failure of the deadline could have severe consequences [12; 13]. Apart from the real-time behavior of MC-IoT, these systems must exhibit properties such as safety, interoperability, and security [14]. The use of cloud technologies has enabled intelligent IoT services as it acts as a server to process and hosts a massive volume of contextual data emitting from edge-nodes of the IoT [15]. The IoT and cloud are so often integrated and so have recently become known as the Cloud of Things (CoT) [15; 16; 17]. A growing trend in CoT is to exploit the cloud as an open platform to connect every digital and physical thing and host the massive amounts of contextual data that benefits from being connected. [PERSON] estimates that more than 25 billion physical devices are expected to be connected to the Internet by the end of 2020, and Cisco estimates that this number will grow to 500 billion by 2030 [18]. When considering IoT systems, regarding both the hardware and software, heterogeneity is very important. In other words, very similar software functionalities are required to be deployed on heterogeneous devices which have a confined set of common core features. Additionally, things may be lightweight, thus having constrained resources and a minimal battery; this makes the situation even more complex concerning the deployment and re-deployment of software functionalities on vastly different devices with different capabilities. On the one hand, the enormous amount of heterogeneous hardware empowering an IoT smart space brings forth an unprecedented opportunity to raise the quality of life. On the other hand, the challenges of heterogeneity, run-time adaptability, privacy, and context-aware processing need to be tackled in order to benefit from the advantages that the IoT can potentially bring [19]. Among IoT systems, an important class is that of MC-IOT systems, i.e., IoT systems running applications whose failure may have severe consequences [19]. As illustrated in a Hewlett Packard Enterprise (HPE) report [5], a survey that involved 200 information technology and business decision-makers, mission-critical computing is becoming increasingly important. As an example, one of the respondents of the performed survey reported: \"Without it [mission-critical computing] we will cease to remain even reasonably competitive in our crowded market\". It is important to note that in mission-critical applications every single element is critical, from the most straightforward RFID tag to a database, to a robot. For what concerns user experience, damage to any of the elements in the mission-critical system would produce the same effect.