This week, I had to change the VirtualCenter certificate in our test environment. Changing the certificate is not that straightforward but there is quite some information available on the net. I used the information in this post: http://lraikhman.blogsite.org/?p=41.

Basically, you use OpenSSL to generate a public/private key pair and a certificate request. You then pass the certificate request to a certificate authority. I used a Microsoft Enterprise CA running on Windows Server 2008. When you obtain the certificate from the CA, you create a pfx file with OpenSSL that contains the private key and the certificate. You can then copy the files to your VirtualCenter server.

Note that when you generate the pfx file with OpenSSL, you will be asked for a password. To use the pfx file, for example to extract the certificate or the private key, the password is needed.

Now if you follow the steps you will be unable to use your existing sysprep customizations in VirtualCenter because the administrator password that is encrypted in the customization file cannot be decrypted. You will see something like:

The reason for this error is quite simple: VirtualCenter cannot get to the data in the pfx file because the password you used to protect the pfx is not correct. It seems that the password you need to use for the pfx file is testpassword. I got that information from here.

To summarize: to change the VC certificate use the steps in http://lraikhman.blogsite.org/?p=41 but when you are asked for the password during pfx creation use testpassword.