How to resolve “vCenter Server Requires Verified Host SSL Certificates Greyed Out” error

Hello Dev, if you’re here, it means you’re facing the “vCenter Server Requires Verified Host SSL Certificates Greyed Out” error. This error usually occurs when you try to add an ESXi host to your vCenter Server, and the “Verify host SSL certificates” option is grayed out. In this article, we’ll guide you through the process of resolving this error.

What are SSL certificates?

Before we dive into the solution, let’s discuss what SSL certificates are. SSL (Secure Sockets Layer) is a security protocol that encrypts communication between a client and a server over the internet. SSL certificates are digital certificates that verify the identity of a website and encrypt the data sent between the website and the browser.

Do I really need SSL certificates?

Yes, you do. SSL certificates are essential in today’s age of cyber threats. Without SSL certificates, your website is vulnerable to attacks like man-in-the-middle (MITM) attacks, where an attacker intercepts and modifies the communication between the client and the server. Not only does this put your website and your customers’ data at risk, but it also harms your reputation.

What is vCenter Server?

vCenter Server is a centralized management tool for VMware vSphere environments. It allows you to manage multiple ESXi hosts from a single interface, making it easier to deploy and manage virtual machines.

What is an ESXi host?

An ESXi host is a physical server that runs the VMware ESXi hypervisor. The ESXi hypervisor allows you to create and manage virtual machines on the server.

What is the “Verify host SSL certificates” option?

When you add an ESXi host to vCenter Server, there is an option called “Verify host SSL certificates”. This option is used to ensure that the SSL certificate presented by the ESXi host is valid and trusted. If this option is not enabled, vCenter Server will not be able to verify the SSL certificate, and your communication with the ESXi host will be insecure.

Why is the “Verify host SSL certificates” option grayed out?

If the “Verify host SSL certificates” option is grayed out, it means that vCenter Server cannot verify the SSL certificate presented by the ESXi host. This usually happens when the SSL certificate is not signed by a trusted root CA (Certificate Authority) or when the SSL certificate is expired or invalid.

How to resolve the “vCenter Server Requires Verified Host SSL Certificates Greyed Out” error

Step 1: Verify the SSL certificate

The first step is to verify the SSL certificate presented by the ESXi host. To do this, you can use the OpenSSL command-line tool. Here’s how:

Command	Description
openssl s_client -connect <ESXi host IP address>:443	Connects to the ESXi host using the SSL/TLS protocol
GET /	Sends an HTTP GET request to the ESXi host
Ctrl + D	Closes the OpenSSL connection

If the SSL certificate is valid and trusted, you should see the SSL certificate information in the output of the OpenSSL command. If the SSL certificate is not valid or trusted, you will see an error message.

Step 2: Add the SSL certificate to the trusted root CAs

If the SSL certificate presented by the ESXi host is not signed by a trusted root CA, you will need to add the SSL certificate to the trusted root CAs on the vCenter Server. Here’s how:

Command	Description
openssl s_client -connect <ESXi host IP address>:443	Connects to the ESXi host using the SSL/TLS protocol
s_client -connect <ESXi host IP address>:443 > esxi.crt	Saves the SSL certificate to a file named esxi.crt
cp esxi.crt /etc/pki/ca-trust/source/anchors/	Copies the SSL certificate to the trusted root CAs directory
update-ca-trust	Updates the trusted root CAs

Step 3: Restart the vCenter Server Appliance

Once you have added the SSL certificate to the trusted root CAs, you will need to restart the vCenter Server Appliance. Here’s how:

Command	Description
systemctl restart vcenter-server	Restarts the vCenter Server Appliance

FAQs

Q. What happens if I don’t enable the “Verify host SSL certificates” option?

If you don’t enable the “Verify host SSL certificates” option, your communication with the ESXi host will be insecure. This means that an attacker can intercept and modify the communication between the vCenter Server and the ESXi host, putting your data and your customers’ data at risk.

Q. How do I know if the SSL certificate presented by the ESXi host is valid and trusted?

You can use the OpenSSL command-line tool to verify the SSL certificate presented by the ESXi host. If the SSL certificate is valid and trusted, you should see the SSL certificate information in the output of the OpenSSL command.

Q. Can I use a self-signed SSL certificate for my ESXi host?

Yes, you can use a self-signed SSL certificate for your ESXi host. However, you will need to add the SSL certificate to the trusted root CAs on the vCenter Server.

Q. Do I need to restart the ESXi host after adding the SSL certificate to the trusted root CAs?

No, you don’t need to restart the ESXi host after adding the SSL certificate to the trusted root CAs. You only need to restart the vCenter Server Appliance.

Q. What other security measures can I take to secure my vSphere environment?

There are several other security measures you can take to secure your vSphere environment, such as enabling strong passwords, using two-factor authentication, and enabling Secure Boot. We recommend that you consult the VMware vSphere Security Configuration Guide for detailed instructions on securing your vSphere environment.

That’s it, Dev! We hope this article was helpful in resolving the “vCenter Server Requires Verified Host SSL Certificates Greyed Out” error. If you have any other questions or concerns, feel free to leave a comment below.