Скачать или смотреть Resolving the x509 certificate signed by unknown authority Error in Kubernetes with k3s

Discover how to fix the common `x509 certificate signed by unknown authority` error when connecting to your k3s installation using kubectl.
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Resolving the x509 certificate signed by unknown authority Error in Kubernetes with k3s

If you've recently installed k3s on a single node and are trying to connect to it remotely using kubectl, you might encounter the frustrating error message: "Unable to connect to the server: x509: certificate signed by unknown authority." This can disrupt your setup and make it challenging to manage your Kubernetes cluster. In this post, we’ll explore why this error occurs and how you can resolve it effectively.

Understanding the Problem

When you try to connect to your k3s server using kubectl, the connection relies on certificate authority (CA) authentication. This error typically arises because your local machine does not recognize the CA that signed the certificate for your k3s server. There are a few common scenarios that can lead to this issue:

You might have copied only the ~/.kube/config file to your local machine without the necessary certificates.

The required CA certificate, client certificate, or client key might be missing or improperly configured.

Step-by-Step Solution

To resolve the x509 certificate signed by unknown authority error, follow these steps:

1. Check the config File

First, verify that your copied config file is set up correctly. The file should have the following structure:

[[See Video to Reveal this Text or Code Snippet]]

2. Copy Required Certificates

If your config file has placeholders pointing to CA root certificates, client certificates, and keys, you need to copy these files from your k3s server to your local machine. Here’s how to find and copy them:

Locate the certificates: On your k3s server, these files are typically located in /etc/rancher/k3s/:

ca.crt: CA root certificate.

client.crt: Client certificate.

client.key: Client key.

Copy the certificates to your machine: Use a secure method (like scp) to transfer these files to your local machine.

[[See Video to Reveal this Text or Code Snippet]]

3. Update Your config File

After copying the certificates, update the config file in ~/.kube/ to point to the local paths of these files. For example:

[[See Video to Reveal this Text or Code Snippet]]

4. Test the Connection

Once your configuration is updated, test the connection again using the command:

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If everything is set up correctly, you should now be able to connect without encountering the x509 certificate signed by unknown authority error.

Conclusion

Dealing with certificate-related errors in Kubernetes can be daunting, but understanding the underlying issues can simplify the process. By ensuring that you have the necessary certificates and have properly configured your kubectl setup, you can avoid the common pitfalls. Following this guide should help you successfully connect to your k3s server without needing to resort to insecure options.

Happy Kubernetes managing!