Resource manager integration in cloud computing environments

A system comprising:

• data processing hardware of one or more first host machines;
• and
• memory hardware in communication with the data processing hardware, the memory hardware storing instructions that when executed on the data processing hardware cause the data processing hardware to perform operations comprising:
• providing a public-cloud computing environment comprising a resource manager that provides a public-cloud resource interface through which one or more public-cloud clients interact with one or more virtual machines;
• receiving a request to create a new private-cloud virtual machine in a private-cloud computing environment of one or more existing private cloud virtual machines implemented by one or more second host machines;
• and
• invoking a private-cloud virtual machine resource provider to create the new private-cloud virtual machine in the private-cloud computing environment by scanning a list of existing private-cloud virtual machines for a private-cloud virtual machine that does not have a counterpart public-cloud virtual machine,
• wherein the new private-cloud virtual machine created by the private-cloud virtual machine resource provider in the private-cloud computing environment is accessible by the public-cloud computing environment via the resource manager.