If your Kubernetes API server requires TLS authentication, you must upload a CA Certificate file, when attaching your cluster (This is optional if your cluster does not require TLS authentication from clients).
You can find the CA Certificate, in the
certificate-authority-data key, of your
~/.kube/config file. The value is base64 encoded in this file. The screen above will accept either plain-text, or base64 encoded strings.
The screenshot below, shows the equivalent value, but is base64 encoded:
~/.kube/config file does not contain a
certificate-authority-data key, then check for a key named
certificate-authority . The value of the
certificate-authority key is a path to a local file that contains the certificate. In this case, you would copy and paste the contents of this file into the screen above.