vCenter Self-Signed Certificates – Part 1

A month ago I had to upgrade one of our customers vCenter from 5.0 to 5.5. We were suppose to run pilot project and upgrade was part of the requirements. However, upgrade was pretty smooth with no unexpected issues or whatsoever. Of course, when I had all components installed I decided to do quick check, though. Login with C# client did not indicate any unusual behavior or possible error, but when open Web Client I saw error message that Web Client could not connect vCenter.


Digging around the log files, I found out that VMware self-signed certificate is 512bits rather than supported 1024/2048bits. Environment was upgraded few times in the past and seems like vCenter installer did not check whether this certificate  meets new version requirements.


With finding the cause first logical step was to search for VMware KB , and of course, I found few

After upgrading to vCenter Server 5.5 Update 1, logging in to vCenter Server reports the error: Failed to verify the SSL certificateKB2074942
Configuring CA signed certificates for vCenter Server 5.5 KB2061973
Configuring CA signed SSL certificates for vSphere Update Manager in vCenter Server 5.1 and 5.5KB2037581
Implementing CA signed SSL certificates with vSphere 5.xKB2034833
Creating certificate requests and certificates for vCenter Server 5.5 componentsKB2061934
Configuring CA signed SSL certificates for the Inventory service in vCenter Server 5.5 KB2061953
Configuring CA signed certificates for vCenter Server 5.5 KB2061973
Implementing CA signed SSL certificates with vSphere 5.xKB2034833
Configuring CA signed SSL certificates for the Inventory service in vCenter Server 5.5KB2061953

So, in order to get this resolved, I had simply to regenerate self-signed certificates and re-register all vCenter components. Pretty easy, isn’t :D. Bellow are the steps I took to fix vCenter self-signed certificates.

Before you start bear in mind following :

  • Certain vCenter Services will be unavailable during process.
  • Replacing the vCenter Server certificate may result in ESXi Hosts becoming disconnected from vCenter Server. You might need to reconnect manually some of the hosts.
  • Plug-in components such as Update Manager, Site Recovery Manager, vCloud Director, Horizon View, etc, may need to be re-registered with vCenter Server.
  • Do not stop vCenter nor any of the it’s components services yourself,SSL Certificate Automation Tool will do that for you during the process.
  • Important: Ensure that you are using OpenSSL Version 0.9.8. If you are using a different version, the SSL implementation would fail.

As first step, we need custom cfg file. In Notepad create new file and call it openssl_config.cfg and add the following lines:


Once, you’re ready save the file and lets begin with certificate generation. Open Command Prompt and go to OpenSSLfolder, located in “C:\Program Files\VMware\Infrastructure\Inventory Service\bin“.


Once the certificates and keys are created, you will need to create a PEM certificate chain. Open Notepad and create new file name it chain.pem save it in same location where certificates and keys are. Open rui.crt and copy content to chaim.pem and save it.

Now we are ready for the fun part. Locate SSL Certificate Automation Tool, unzip it and go to folder. In order to save some time and don’t type multiple times same things, we will need to edit ssl-environment.bat file. Open file in Notepad or any other editor and change following lines:

Save the file and run ssl-updater.bat as Administrator.

On “Main Menu”  select  1.Plan Your Steps to upgrade SSL certificates to get detailed plan how to implement generated certificates.


Now we have the plan for re-establishing the trust between vCenter and it’s components.Let’s start with first step Update the vCenter Server SSL certificate.

Go to Main Menu > Update the vCenter Server > Update the vCenter Server SSL certificate  and follow the wizard.


Note: If you’re using SQL Express your Database password would be your domain admin or local admin password .Microsoft SQL Express support only Windows Authentication.

If you see error ERROR: The leaf certificate doesn’t have any CN or subjectAltName that matches the public address of the current machine. Rejecting the chain. To skip this

check, set the `ssl_tool_no_cert_san_check’ environment variable to 1.

Add following  “set ssl_tool_no_cert_san_check=1″ to lines 680 and 759 and re-open ssl-updater.bat


Next step is to re-establish the trust between vCenter and Inventory service. From Main Menu > Update the vCenter Server SSL certificate > Update vCenter Server trust to Inventory Service


Next step is to re-establish the trust between Inventory Service and vCenter. From Main Menu > Update Inventory Service > Update the Inventory Service trust to vCenter Server.


Next step is to re-establish the trust between vCenter and vCenter Orchestrator. From Main Menu > From Main Menu > Update vCenter Orchestrator > Update vCenter Orchestrator trust to vCenter Server


Next step is to re-establish the trust between vCenter and WebClient. From Main Menu > Update vSphere Web Client and Log Browser > Update vSphere Web Client trust to vCenter Server


Last step in the process is VUM .From Main Menu > Update vSphere Update Manager > Update vSphere Update Manager trust to vCenter Server


After you complete all steps, login to VMware Web Client and enjoy !

The whole procedure is time consuming,complicated and not well documented. If you want to change certificates for each one of vCenter components you can follow same steps.In next part I will describe how to work with CA certificates.

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  1. Mike – I’m getting the following:
    [Mon 05/09/2016 – 22:18:22.79]: Validating the input parameters…
    HTTPError: Unable to open or read page.
    HTTP Error 401: basic auth failed
    [Mon 05/09/2016 – 22:18:46.46]: “Cannot log in to vCenter.”
    [Mon 05/09/2016 – 22:18:46.47]: The vCenter certificate update failed.

    Any ideas? This is in a default vCenter 5.5 clean install – I’m also getting the same at a client site. So – I must be doing something wrong.

  2. Hi ,
    I am getting error : key file does not contain a private key or the private key is encoded using unsupported format . Supported key encoding schemes are : PKCS#1 and PKCS#8

  3. Excellent tutorial. However when i got to the SSL updater it failed because the keysize was too small (1024). I therefore simply updated the default_bits setting in openssl.cfg to resolve this, deleted all the keys created in my temp folder and started again.
    Also you need to make sure the d:\temp folder has been created before starting, in my case i made one on c:\.
    Finally one my system the “openssl_config.cfg” is actually called “openssl.cfg”, so i needed to update the commands accordingly.

    Anyway thanks !

  4. Pingback: Unable to migrate VirtualCeneter to 6.5 from 5.5. Certificate errors. – Tips and Tricks

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