## 6 The Road Ahead
### Overcoming Conceptual Centralized Approaches
However, leveraging P2P technologies for service provisioning has been identified of particular interest for research, and one of the challenges is how to enable the service providers to adapt themselves in response to changing service demand [59]. One astonishing curve in Figure 10 is the research interest in serverless solutions. Although on a substantially lower absolute level, a constant research interest in serverless solutions can be observed since 1995. To have \"serverless\" solutions seems to be a long-standing dream in computer science. The reader should be aware that the notion of serverless changed over time. Serverless has been used until 2000 very often in file storage research contexts. With the rise of P2P based solutions, the term serverless has been mainly used alongside P2P based approaches. In addition, since 2015, much momentum has been given alongside cloud-native application architectures (see Figure 11). Thus, nowadays, it is mainly used in the notion described in Sections 5.1.3 and 5.2.2. Figure 10: Trends of papers dealing with the terms cloud-computing, serverless, P2P, and blockchain (as the latest P2P based trend). Retrieved from Scopus (limited to computer science), 2018 extrapolated. Figure 11 shows some further interesting correlation. With the rise of cloud computing in 2008, there is a steady decline in SOA related research. Thus, to deploy monolithic SOA applications in the cloud was not seen useful from the very beginning of cloud computing. However, it took almost five years in research to investigate further and more cloud suited application architectures (microservice and serverless architectures). If we look at Figures 10 and 11, we see a decline of classical architecture approaches like SOA and a rising interest in new architecture styles like microservice and serverless architectures. Again, especially serverless architectures come along with some decentralizing philosophy that is observable in P2P based research as well. The author does not think that those cloud application architectures will strive for the same level of decentralizing and distribution like peer-to-peer based approaches. However, a more distributed service-to-service trend is observable in cloud application architecture research [60]. Thus, the cloud computing trend started a decline in SOA (see Figure 11) and P2P (see Figure 10). However, if we compare SOA and P2P (including blockchain related research), we see an increasing interest in decentralized solutions again (see Figure 12). If we are taking all this together to forecast the road ahead, we could assume that new architecture styles like microservices and serverless architectures will dominate service computing. Moreover, SOA seems to die. However, we see a resurgence of interest in decentralized approaches known from P2P related research. Therefore, the author assumes that especially serverless architectures will more and more evolve into cloud application architectures that follow distributed service-to-service principles (much more in the notion of peer-to-peer). Figure 11: Trends of papers dealing with cloud-computing, SOA, microservices and serverless. Retrieved from Scopus (limited to computer science), 2018 extrapolated. Figure 12: Trends of papers dealing with SOA, and P2P (including blockchain). Retrieved from Scopus (limited to computer science), 2018 extrapolated.