What is CUmulus? 

CU Research Computing hosts a free-to-use on-premise cloud service, called CUmulus, which supports cases not well-suited for HPC such as webservers, databases, and long-running services. The CUmulus service includes access to a Virtual Private Cloud (VPC) which provides users with a logically isolated section of the cloud with a small number of outside routable floating IP addresses. Within this VPC customers will be given an allocation of the following resources which can be used to host virtual machines and volumes to host workloads.:

  • CPU cores
  • Memory
  • Storage

The CU Research Computing group would like to acknowledge support of this project from the National Science Foundation (OAC-1925766)


  • Dedicated compute resources – no scheduling or waiting in line 
  • On premise cloud offering based on OpenStack platform (CUmulus) 
  • Integration with other CURC resources (Summit, Alpine, Blanca, Petalibrary) - enabled 
  • Virtual machine creation
  • Storage volume creation/snapshot
  • Basic Infrastructure monitoring
  • Assignment of routable “floating IPs” (e.g., for web-hosting)
  • High availability in the event of underlying hardware failure
  • Load balancing of virtual resources across multiple physical machines
  • Console access to hosted VMs

Who can get it

CUmulus is a free-to-use cloud system for CU Boulder and RMACC users with capacity reserved to:

  • No more than 80% of cycles: CU Boulder faculty, staff, students, and affiliates
  • At least 20% of cycles: RMACC affiliates (CSU, Wyoming, UC system campuses, and many more)

To ensure optimal usage, unused cycles are preemptively available to the Open Science Grid (OSG)

Email rc-help@coloorado.edu