Scalability and Openness are the focus of an agile data center. Scalability refers to the ability of a data center to adapt to changing demands and workloads by adding or removing resources dynamically. Openness refers to the use of open standards and interfaces that enable interoperability and integration of different technologies and vendors in a data center. An agile data center can provide flexible, efficient, and cost-effective services to customers and applications, while reducing operational complexity and overhead. Fixed Architecture and Closed Cloud System are not the focus of an agile data center. Fixed Architecture means a rigid and predefined structure of a data center that cannot be easily modified or customized. Closed Cloud System means a proprietary and isolated cloud platform that does not support compatibility or collaboration with other cloud platforms or services. A fixed architecture and a closed cloud system can limit the performance, functionality, and innovation of a data center, and increase the dependency and lock-in of customers and applications. Reference: Nokia Bell Labs 5G Professional Certification - Distributed Cloud Networks, Unit 1: Cloud Ecosystem, Section 1.3: Cloud Agility.