How to Fix "x509: certificate has expired or is not yet valid" Error in MicroK8s

If you're using MicroK8s for your Kubernetes development and you encounter the "x509: certificate has expired or is not yet valid" error, don't worry; it's a common issue, and we have a straightforward solution for you.

This error typically occurs when the certificates used by MicroK8s have either expired or are not yet valid. Here's how you can resolve it:

Step 1: Check Certificate Expiration

First, let's check the expiration time of all installed certificates by running the following command:

sudo microk8s.refresh-certs -c

This command will display the expiration times of certificates. Similar to the response below;

The CA certificate will expire in 3274 days.
The server certificate will expire in 0 days.
The front proxy client certificate will expire in -11 days.

Step 2: Refresh Server Certificate

If you notice that the server certificate (server.crt) has expired or is near expiration, you can refresh it using the --cert flag followed by the desired certificate option:

sudo microk8s.refresh-certs --cert server.crt

This will generate a new server certificate with updated expiration dates.

Similarly, if the front proxy client certificate (front-proxy-client.crt) is expired or about to expire, you can refresh it with this command:

sudo microk8s.refresh-certs --cert front-proxy-client.crt

Step 3: Verify the Changes

After running these commands, your MicroK8s cluster should have updated certificates. You can verify the changes by checking the certificate expiration times again:

sudo microk8s.refresh-certs -c

Step 4: Restart MicroK8s (if needed)

In some cases, you may need to restart MicroK8s to ensure that the new certificates take effect:

sudo microk8s stop
sudo microk8s start

That's it! You've successfully fixed the "x509: certificate has expired or is not yet valid" error in MicroK8s. Your Kubernetes cluster should now be up and running smoothly.

Remember that regularly checking and refreshing certificates is a good practice to avoid such issues in the future.

Happy Kubernetes development!