vSphere includes the VMware Certificate Authority (VMCA). By default, the VMCA creates all internal certificates used in vSphere environment. It generates certificates for newly added ESXi hosts and storage VASA providers that manage or represent Virtual Volumes storage systems.
Communication with the VASA provider is protected by SSL certificates. These certificates can come from the VASA provider or from the VMCA.
Certificates can be directly provided by the VASA provider for long-term use. They can be either self-generated and self-signed, or derived from an external Certificate Authority.
Certificates can be generated by the VMCA for use by the VASA provider.
When a host or VASA provider is registered, VMCA follows these steps automatically, without involvement from the vSphere administrator.
When a VASA provider is first added to the vCenter Server storage management service (SMS), it produces a self‐signed certificate.
After verifying the certificate, the SMS requests a Certificate Signing Request (CSR) from the VASA provider.
After receiving and validating the CSR, the SMS presents it to the VMCA on behalf of the VASA provider, requesting a CA signed certificate.
The VMCA can be configured to function as a standalone CA, or as a subordinate to an enterprise CA. If you set up the VMCA as a subordinate CA, the VMCA signs the CSR with the full chain.
The signed certificate with the root certificate is passed to the VASA provider. The VASA provider can authenticate all future secure connections originating from the SMS on vCenter Server and on ESXi hosts.