Final answer:
To check if a kubectl certificate has expired, run 'kubectl config view --raw', extract the 'client-certificate-data', decode it from base64, and inspect the certificate's validity period using a tool like 'openssl' to see the 'Not After' date.
Step-by-step explanation:
To check if your kubectl certificate has expired, you can use the following command:
kubectl config view --raw
This command will print out your kubeconfig file in its raw format including all the certificates. Look for the client-certificate-data field associated with your user. This field contains your client certificate encoded in base64.
To decode and check the expiry date of your certificate, you can perform the following steps:
Copy the base64 encoded certificate data (excluding the headers).
Decode the certificate data from base64. You can use online tools or a command line tool like base64.
Use an SSL parsing tool or command to read the certificate. For example, the openssl command:
openssl x509 -in decoded-cert.pem -text -noout
You should look for the Validity period within the output. It will show the Not Before and Not After dates indicating the duration for which the certificate is valid. Your certificate is considered expired if the current date is beyond the Not After date stated.