Microservice Architecture (MSA) is an architectural style that aims to build a software application as a set of small services independently deployable. When adopting MSA, companies must drive some aspects that impact the organizational efficiency in order to guarantee: (i) the strategic benefits of the initiative; (ii) promote the best resources usage; and (iii) separate the essential decisions to enterprise architecture management (EAM) delegating other aspects to microservice teams. This paper assesses the relevant factors about MSA from the EAM view in order to propose an ArchiMate metamodel which enables enterprise architecture (EA) governance of MSA.
Microservices are components that individually present low complexity, however, a
microservice-based systems architecture becomes highly complex due to its
heterogeneity of technology, volatility and high granularity [
Characteristic Decentralized Governance Scalability Well-Defined Interface API
Despite the high autonomy of microservices teams, EAM still needs to support teams on cross issues of services but playing a more consultative role than in traditional IT. It focuses on making recommendations instead of allowing or disallowing certain architectural decisions while still supporting cross-microservice architecture development, keeping track of permanent changes in IT architecture and providing information to enable cost transparency. 3
Based on The Open Group MSA Governance Framework [2], we propose a diagram to clarify the concerns of EA and Microservice governance scopes, showed in Fig. 1. The idea is that any governance object that emerges should update this figure to visually guide what should be governed by EAM and what should not.
To help the microservice team to choose the best technology to implement their needs, the EAM model provides a catalog of some important technologies which consider their relevance when it comes to knowledge and costs managements. Fig. 2 is an adaptation of the model proposed by The Open Group [4] enriched by some other aspects provided by Yale et al. [3]. It exemplifies artifacts that represent governance recommendations or requirements for microservices, observing that everything inside of inner architecture is just a recommendation for microservices, aiming to avoid the risks in having too many technologies, but without restricting the innovation.
Keeping in mind that it is desirable to delegate as many decisions as possible to the microservice team, we propose the matrix in Fig. 3 which defines the responsibilities of governance roles over each architectural property.
In this matrix the lines represent the governance concerns identified in Fig. 1. Principles and Governance Scopes (Adapted from [2])), and the columns architectural components and their relations identified in Fig. 2. Enterprise Microservice Reference Architecture). The cells indicate if the principal responsibility resides in Enterprise Team Governance (ET), autonomously in the Microservice Team (MT), or in the Microservice team within enterprise Restrictions or Recommendation (MR). 4
The proposed solution resulted in an ArchiMate model defining principles, governance responsibilities, and a technology architecture view for MSA at EAM level. However, the assumptions made for the development of this paper regarding the existence of the difficulty for companies to maintain the alignment between MSA and EAM in relation to IT governance, as well as the aspects discussed and addressed to the EAM in the context of this paper, still need confirmation. Lastly, the model proposed should be applied and evaluated in a real case, and other theoretical strategies can be investigated to validate and enrich the solution.
This work was supported by national funds through Fundação para a Ciência e a Tecnologia (FCT) with reference UID/CEC/50021/2019 and by the European Commission program H2020 under the grant agreement 822404 (project QualiChain).