On Thursday, Mesosphere announced the finalization of $73.5M in Series C funding led by strategic investor Hewlett Packard Enterprise with additional participation from Microsoft, a new strategic investor, in conjunction with previous investors Andreessen Horowitz, Fuel Capital, Khosla Ventures, and new investors A Capital and Triangle Peak Partners. Mesosphere’s Data Center Operating System (DCOS) helps companies manage hyper-scale data centers as if they were one unit in addition to facilitating the operationalization of distributed applications, containers, micro-services and Big Data within cloud-based and on-premise environments. The San Francisco-based startup boasts customers such as Microsoft, HP, Yelp and eBay and currently staffs approximately 125 employees. The funding raise will be used to enhance its engineering operations in addition to expanding its sales and support teams. Microsoft and HPE remain likely acquirers of Mesosphere, particularly given Mesosphere’s collaboration with Microsoft on the Azure Container Service and Mesosphere’s partnership with HPE to leverage HPE hardware. The biggest news from today’s funding announcement is Microsoft’s participation as a new strategic investor, which corroborates reports that Microsoft attempted to purchase Mesosphere last year for approximately $150M. The $73.5M in Series C funding round brings the total capital raised by Mesosphere to $126M. In addition to the funding raise, Mesosphere today announced the release of Marathon 1.0, an enterprise-grade orchestration platform and a new product, Velocity, a continuous improvement and continuous development tool for its DCOS that uses the open source Jenkins framework.