Multi-cloud infrastructure refers to a data center environment that uses multiple cloud computing services. It offers increased flexibility and redundancy, as well as improved disaster recovery capabilities. The main reasons for adopting multi-cloud infrastructure include avoiding vendor lock-in, ensuring fault tolerance, and catering to different customer demands. Key advantages of multi-cloud infrastructure include supporting various use cases and customer requirements, leveraging rapid cloud provider iterations, and making architecture decisions that facilitate multi-cloud. To successfully implement multi-cloud infrastructure, it is crucial to choose the right tools and set up processes, modularize core components in IaC, and make architectural decisions that support multiple clouds.