VMware vCenter Appliance 6.7 (VCSA) SSL Certificates using Let’s Encrypt

By | 2019-02-03

From time to time I got nerved about the missing trust of my demo VMware vCenter Server. Since I’m using Let’s Encrypt (LE) for years for my blog and other sites, I thought about also using this nice service for my vCenter Server:

After playing around a bit with the vSphere 6.7 Certificate Manager, I found a nice (but dirty) solution:

The following is a very quick & dirty solution and I will not explain what the Certificate Manager does exactly. If you are interested in all of its features, please just read the documentation first ūüôā

Let’s start. First of all, you need two requirements: you cannot run the LE stuff on your vCenter Server Appliance, so you need a linux host for doing this. Because you are running LE on a different ip than your vCenter Server, you need a DNS record of type TXT for verification. Let’s start on our linux host:

linux:/root # certbot certonly --manual --preferred-challenges=dns -d vcenter.ich-halt.net

While using this wizard, you need to create your TXT DNS record, for example:

linux:/root # dig TXT _acme-challenge.vcenter.ich-halt.net +short

After the LE wizard ran successfully, you got the three needed files for your vCenter Server:

linux:/etc/letsencrypt/live/vcenter.ich-halt.net # ls
(...) cert.pem  fullchain.pem  privkey.pem

Just copy these files to your vCenter Server Appliance, switch to its shell (login via ssh) and run the Certificate Manager:

root@vcenter [ ~ ]# /usr/lib/vmware-vmca/bin/certificate-manager
  1. Replace Machine SSL certificate with Custom Certificate

Option[1 to 8]: 1

2. Import custom certificate(s) and key(s) to replace existing Machine SSL certificate

Option [1 or 2]: 2

Please provide valid custom certificate for Machine SSL.
File : /root/cert.pem

Please provide valid custom key for Machine SSL.
File : /root/privkey.pem

Please provide the signing certificate of the Machine SSL certificate
File : /root/fullchain.pem

You are going to replace Machine SSL cert using custom cert
Continue operation : Option[Y/N] ? : y

For vCenter Server Appliance 6.5 this works fine. But (in my setup) with version 6.7 it doesn’t. You get some errors and the Certificate Manager will perform a revert of your changes:

Updated 0 service(s)
Status : 85% Completed [starting services...]                  
Error while starting services, please see service-control log for more details
Status : 0% Completed [Operation failed, performing automatic rollback]
Error while replacing Machine SSL Cert, please see /var/log/vmware/vmcad/certificate-manager.log for more information.

Performing rollback of Machine SSL Cert...

To prevent from this revert, you need to press CTRL + C instant after this “Updated 0 service(s)” and reboot your VCSA with “reboot”.

Get service 86b7419e-7b41-4aa1-9bc6-5eb01cb860ad
Don't update service 86b7419e-7b41-4aa1-9bc6-5eb01cb860ad
Updated 0 service(s)

After coming up again, all my services started correct and are using the LE certifiate:

Next step will be the challenge to automate the LE certificate renewal ūüôā

Appendix:¬†maybe¬†it¬†isn’t¬†a¬†generell¬†vSphere¬†6.7¬†problem¬†–¬†now¬†I have¬†found¬†a¬†VCSA¬†6.7¬†which¬†worked¬†like¬†6.5¬†without¬†problems¬†…

2 thoughts on “VMware vCenter Appliance 6.7 (VCSA) SSL Certificates using Let’s Encrypt

  1. Joseph

    Did you ever manage to figure out why the service startup failed at 85% and a rollback was initiated? I’m having the same problem on vCenter 6.7.

  2. W

    I had similar issue,
    rollback starts, becouse service vpxd won’t start.
    > ExpectedPeerName: localhost
    > Host name does not match the subject name(s) in certificate.)

    but why it expect ‘localhost’ SSL certificate?! I don’t know.


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