This is a plugin for nagios to check the health of vsan clusters. It uses the VMware python SDK avilable from VMware: https://www.vmware.com/support/developer/vapi/index.html
VMware Virtual SAN SDK for Python depends on pyVmomi (v6.0.0) - the Python SDK for the VMware vSphere API. You should know how to use pyVmomi before trying this SDK. Please refer to https://github.com/vmware/pyvmomi for pyVmomi documentation and software.