tlscheck

tlscheck - Kubernetes TLS Certificate Expiration Checker

This program lists the TLS certificates used in Kubernetes secrets of type kubernetes.io/tls and shows their remaining lifetime (in days). It can be useful for monitoring certificate expiration and taking timely action to renew them.

Features

• Retrieves all the namespaces in the cluster
• Lists all the secrets of type kubernetes.io/tls within each namespace
• Decodes and parses the certificates
• Calculates the remaining lifetime of each certificate in days
• Displays the results in a tabular format

Prerequisites

• Go 1.16 or higher
• Access to a Kubernetes cluster (kubeconfig or in-cluster configuration)
• Kubernetes client-go library

Installation

1. Clone the repository:

git clone https://github.com/stianfro/tlscheck.git
cd tlscheck

1. Build the binary:

go build -o tlscheck

1. Move the binary to a directory in your $PATH:

sudo mv tlscheck /usr/local/bin/

Usage

Run the program:

tlscheck

The output will be displayed in the following format:

SECRET_NAME                    NAMESPACE                       ISSUER                          REMAINING_LIFETIME (days)
example-tls-secret             default                         CN=example.com                  89
another-tls-secret             kube-system                     CN=another-example.com          150
...

Contributing

Feel free to open issues or submit pull requests if you find any bugs or have suggestions for improvements. Your contributions are always welcome!

License

This project is licensed under the MIT License.