Generate CSR with vSphere Certificate Manager and Prepare Root Certificate (Intermediate CA)

You can use vSphere Certificate Manager to generate Certificate Signing Requests (CSRs). Submit those CSRs to your enterprise CA or to an external certificate authority for signing. You can use the signed certificates with the different supported certificate replacement processes.

• You can use vSphere Certificate Manager to create the CSR.
• If you prefer to create the CSR manually, the certificate that you send to be signed must meet the following requirements.
  • Key size: 2048 bits (minimum) to 16384 bits (maximum) (PEM encoded)
  • PEM format. VMware supports PKCS8 and PKCS1 (RSA keys). When keys are added to VECS, they are converted to PKCS8.
  • x509 version 3
  • The CA extension must be set to true for root certificates, and cert sign must be in the list of requirements. For example:

    basicConstraints        = critical,CA:true
    keyUsage                = critical,digitalSignature,keyCertSign

  • CRL signing must be enabled.
  • Extended Key Usage can be either empty or contain Server Authentication.
  • No explicit limit to the length of the certificate chain. VMCA uses the OpenSSL default, which is 10 certificates.
  • Certificates with wildcards or with more than one DNS name are not supported.
  • You cannot create subsidiary CAs of VMCA.

    See the VMware knowledge base article at http://kb.vmware.com/kb/2112009, Creating a Microsoft Certificate Authority Template for SSL certificate creation in vSphere 6.x, for an example using Microsoft Certificate Authority.

Prerequisites

vSphere Certificate Manager prompts you for information. The prompts depend on your environment and on the type of certificate that you want to replace.

For any CSR generation, you are prompted for the password of the [email protected] user, or for the administrator of the vCenter Single Sign-On domain that you are connecting to.

Procedure

1. Run the vSphere Certificate Manager.
   /usr/lib/vmware-vmca/bin/certificate-manager
2. Select Option 2.
   Initially, you use this option to generate the CSR, not to replace certificates.
3. Supply the password and the vCenter Server IP address or host name if prompted.
4. Select Option 1 to generate the CSR and answer the prompts.
   As part of the process, you have to provide a directory. Certificate Manager places the certificate to be signed ( *.csr file) and the corresponding key file ( *.key file) in the directory.
5. Name the certificate signing request (CSR) root_signing_cert.csr.
6. Send the CSR to your enterprise or external CA for signing and name the resulting signed certificate root_signing_cert.cer.
7. In a text editor, combine the certificates as follows.

   -----BEGIN CERTIFICATE-----
   Signed VMCA root certificate
   -----END CERTIFICATE-----
   -----BEGIN CERTIFICATE-----
   CA intermediate certificates
   -----END CERTIFICATE-----
   -----BEGIN CERTIFICATE-----
   Root certificate of enterprise or external CA
   -----END CERTIFICATE-----

8. Save the file as root_signing_chain.cer.

What to do next

Replace the existing root certificate with the chained root certificate. See Replace VMCA Root Certificate with Custom Signing Certificate and Replace All Certificates.