VMware: How-to Secure our vCenter Server 7 (VCSA) with a ZeroSSL Certificate

Greetings friends, for many years, changing or adding an SSL certificate to our VMware vCenter has been a real pain, there are tens of KB, and hundreds of posts in the Community with errors of all kinds once you flirt with the steps. But from 6.7 onwards it seems that the process has been simplified a lot, so today I come to show you the steps to install your own SSL Certificate in VCSA, which is also free created with ZeroSSL. After the Let’s Encrypt drama with the CA expiring, and so on, I’ve decided to go and explore other 90 days free alternatives and I came across ZeroSSL, so let’s dive into it.

How to request a free 90-day ZeroSSL Certificate

Let’s start by registering an account with them, they do not ask for more than an email and a password, which is always nice. Once we have the account created, we can go to create new certificate:

We should introduce our valid FQDN from our vCenter, on my case you can clearly see that I am requesting an SSL certificate for an FQDN called vcsa-7.jorgedelacruz.es, click in Next Step:

We need to make sure that we select just 90-Day Certificate, which is the free one, select that and click in Next Step:

We are not going to create a CSR or anything from our vCenter, so we can leave the default option and click in Next Step:

Just to make sure, make sure the Free option is selected, it would be if 90-day have been selected before, click Next Step:

Now, we need to verify the FQDN, the domain, I usually prefer and like more a DNS with a CNAME, as I am using SplitDNS, meaning I have a jorgedelacruz.es DNS Zone for the Internet, which resolves my website, my mail, and others, to Public IPs, and my internal jorgedelacruz.es DNS Zone which resolves to my AD, my VMs, ESXi, VCSA, etc. As you can see here it is asking us to create a public CNAME, with a name, and with a point to, grab those two things:

How to properly add the DNS requirements for ZeroSSL

Alright, so the first step will be to follow the requirement, and inside our public DNS, in my case it is Cloudflare, generate a new CNAME on my jorgedelacruz.es, like this (make sure the Proxy status is off):

But this is not everything, ZeroSSL uses another DNS entry which is called CAA (A Certification Authority Authorization (CAA) record is used to specify which certificate authorities (CAs) are allowed to issue certificates), meaning we need to create a CAA entry pointing to what ZeroSSL recommends, it will look like this (you need to create an entry to your FQDN, pointing to sectigo.com, with the Tag Only allow specific hostnames better, type CAA remember:

Yes! You are almost done, we can go back to our ZeroSSL website and click on Verify Domain:

If you have introduced both DNS as described, you should see the next message, try a few times it fails, and comment here if it does not work:

How to make VMware vCenter Server Appliance happy with an SSL certificate

This is not an easy task, VMware VCSA it is extremely picky with the SSL certificates, it requires the Root Certificate to be inside the files in order to make it work. So at this point, from ZeroSSL you have three files:

private.key
certificate.crt
ca_bundle.crt

You need to download the extra Root Certificate, at the moment of writing this have made the trick for me – https://crt.sh/?d=1282303295 but you can find a full page with more root certificates here – https://sectigo.com/knowledge-base/detail/Sectigo-Intermediate-Certificates/kA01N000000rfBO some other users have tried with the SHA-2 Root : USERTrust RSA Certification Authority on that website (it expires in 2038, so probably a good option)

But, what VMware is expecting? Let me explain, VMware will be absolutely happy, without errors, if you provide to it the next:

My fullchain.pem looks like this, just in case you want to copy-paste, as you can reuse it as you can see for the cert.pem as well, where you add it after the SSL certificate:

Install ZeroSSL SSL Certificate in VCSA with certificate-manager via shell

As we are still inside our VCSA by the shell, we can make use of the new certificate manager that is included in a few editions, to invoke it as simple as launching:

/usr/lib/vmware-vmca/bin/certificate-manager

That will show us the following menu, we will press 1:

                 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
                |                                                                     |
                |      *** Welcome to the vSphere 6.8 Certificate Manager  ***        |
                |                                                                     |
                |                   -- Select Operation --                            |
                |                                                                     |
                |      1. Replace Machine SSL certificate with Custom Certificate     |
                |                                                                     |
                |      2. Replace VMCA Root certificate with Custom Signing           |
                |         Certificate and replace all Certificates                    |
                |                                                                     |
                |      3. Replace Machine SSL certificate with VMCA Certificate       |
                |                                                                     |
                |      4. Regenerate a new VMCA Root Certificate and                  |
                |         replace all certificates                                    |
                |                                                                     |
                |      5. Replace Solution user certificates with                     |
                |         Custom Certificate                                          |
                |         NOTE: Solution user certs will be deprecated in a future    |
                |         release of vCenter. Refer to release notes for more details.|
                |                                                                     |
                |      6. Replace Solution user certificates with VMCA certificates   |
                |                                                                     |
                |      7. Revert last performed operation by re-publishing old        |
                |         certificates                                                |
                |                                                                     |
                |      8. Reset all Certificates                                      |
                |_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|
Note : Use Ctrl-D to exit.
Option[1 to 8]: 1

This will ask us for credentials with permissions to operate the SSL Certificates within vsphere.local (or your SSO), in my case I will use administrator:

Please provide valid SSO and VC privileged user credential to perform certificate operations.
Enter username [[email protected]]:
Enter password:

Now we will select the second option to select our own SSL Certificate

1. Generate Certificate Signing Request(s) and Key(s) for Machine SSL certificate
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

And we will already select yes in this last question, the services will be restarted automatically:

You are going to replace Machine SSL cert using custom cert
Continue operation : Option[Y/N] ? : y
Command Output: /root/cert.pem: OK

Get site nameCompleted [Replacing Machine SSL Cert...]
default-site
Lookup all services
Get service default-site:c528e353-4680-4885-9e07-6d1d5b5b632d
Don't update service default-site:c528e353-4680-4885-9e07-6d1d5b5b632d
Get service default-site:612774a5-5093-4eaa-892c-d5735d3af0fe
...
Get service 9ae1be99-aabd-47a5-bd9a-f97f74eaf78f_com.vmware.vcenter.wcp
Don't update service 9ae1be99-aabd-47a5-bd9a-f97f74eaf78f_com.vmware.vcenter.wcp
Updated 0 service(s)
Status : 100% Completed [All tasks completed successfully]

Check that our VCSA already has the new valid SSL Certificate

The moment of truth has arrived, we will go to our vCenter, remember that the certificate is only valid for the FQDN, if you access by IP it will always come out that it is not secure, and if it is the FQDN we will see the so desired green lock:

In addition, we can see when the SSL certificate expires, properties, etc:

If we want to monitor our SSL Certificate to see when it expires so that we can renew it, I have a ticket for that:

Looking for the Perfect Dashboard: InfluxDB, Telegraf, and Grafana – Part XX (Monitoring SSL Certificates x.509)

That’s all friends, I hope you like it and find it useful. A big greeting.

Comments

willdashwood says

20th October 2021 at 3:00 pm

Thank you for this post. I was following your previous guide for using Let’s Encrypt and failing. In the end, I bought an SSL from Comodo and I used your incredibly useful image which shows how the certificates should be bundled and it worked first time using the web GUI! Didn’t even have to resort to command line.

The only issue I have is that Certificate Management page in vSphere Client, I get the warning “Error occurred while fetching machine certificates: com.vmware.vcenter.certificate_management.vcenter.tls” and it doesn’t show any of the certificates installed. It’s not a big deal but is that something you’ve seen? Perhaps it’s because of all the previous attempts to install an SSL!

Also do you know where the private key is stored? I used vSphere to generate the CSR so I want to make sure the private key is backed up to save me rekeying the SSL in the event of redeploying vSphere. Thanks!

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Vipin says

24th October 2021 at 5:10 am

THANK YOU VERY MUCH FOR THIS POST. I was going through the same issue as you had with letsencrypt (spent 50hrs with no luck).

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jorgeuk says

24th October 2021 at 10:20 am

Glad it helped, I have not gave up just yet on Let’s Encrypt maybe the new root 2 will help, but it is limited for now.

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Simon Wilmann (@mllii) says

15th February 2022 at 11:39 pm

wondering if this could be automated with acme.sh? https://github.com/acmesh-official/acme.sh
been trying to get this to work with vcenter 7.0.3 but update manager is not happy.

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jorgeuk says

16th February 2022 at 10:14 am

Will give it a try later on, after multiple battles with let’s encrypt, then zerossl to the rescue, the last time it expired I came back into self-signed to avoid issues.

Will give it a try for sure.

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Gilou says

25th October 2022 at 11:06 am

Hi Folks.
Thanks to JorgeUK for all his tutos about SSL (Let’s Encrypt, ZeroSSL) and VCSA (6,7).
I’m trying to set up a free SSL certificate (nevermind the CA) with an automated renewal process on my 7.0.3 VCSA.
Dear Jorge, do you have a tuto for that ? 😉

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jorgeuk says

25th October 2022 at 1:17 pm

Hello,
Which provider exactly, Gilou? Cheers

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Gilou says

25th October 2022 at 7:53 pm

It seems ZeroSSL is the best choice at this moment: they offer (like you showed) free 3-monthes SSL certificates and I hope it will be possible to acme.sh for automatization…
thanks for your answer
Regards

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Johan says

24th January 2023 at 4:13 pm

Is this working for anyone on 7.0.3 Update 3j? Certificate Manager via CLI says that all certificates are replaced successfully, but Update Manager / Lifecycle Manager refuses to start after the certificate replacement…

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Frank says

28th March 2023 at 3:06 pm

Saved my life mate. Was ripping what’s left of my hair out! Cheers.

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