  Microservices have become popular in the past few years, attracting the
interest of both academia and industry. Despite of its benefits, this new
architectural style still poses important challenges, such as resilience,
performance and evolution. Self-adaptation techniques have been applied
recently as an alternative to solve or mitigate those problems. However, due to
the range of quality attributes that affect microservice architectures, many
different self-adaptation strategies can be used. Thus, to understand the
state-of-the-art of the use of self-adaptation techniques and mechanisms in
microservice-based systems, this work conducted a systematic mapping, in which
21 primary studies were analyzed considering qualitative and quantitative
research questions. The results show that most studies focus on the Monitor
phase (28.57%) of the adaptation control loop, address the self-healing
property (23.81%), apply a reactive adaptation strategy (80.95%) in the system
infrastructure level (47.62%) and use a centralized approach (38.10%). From
those, it was possible to propose some research directions to fill existing
gaps.
