Kubernetes Certificate Management: Everything You Need to Know
Kubenatives Newsletter - Edition #14
If you’re running a Kubernetes cluster with kubeadm
, you might think certificates are just a "set-and-forget" feature—but they’re crucial to securing your cluster.
In this issue, we’ll cover everything about Kubernetes certificates, including:
✅ How Kubernetes uses certificates
✅ Where certificates are stored
✅ Certificate expiration and renewal
✅ CA certificate management
✅ Automating certificate rotation
✅ Handling internal CAs in secure enterprise environments
✅ How update-ca-trust
works in Linux
By the end, you'll have a solid understanding of Kubernetes certificate management and the tools to ensure your cluster remains secure and operational.
Let’s dive in! 🚀
How Kubernetes Uses Certificates
Kubernetes uses TLS certificates for secure communication between:
🔹 The API server and kubelet
🔹 The API server and etcd
🔹 The API server and the controller manager, scheduler, and other control plane components
🔹 Users (kubectl
) accessing the API server
🔹 External services interacting with Kubernetes
Each component authenticates with certificates to ensure that no unauthorized services can communicate with the cluster.
Where Kubernetes Stores Certificates
When you create a cluster using kubeadm
, it automatically generates certificates and stores them in:
📁 /etc/kubernetes/pki/
Here’s a breakdown of key files:
Each of these certificates plays a role in securing different parts of the Kubernetes cluster.
Checking Kubernetes Certificate Expiry
Kubeadm-generated certificates expire after 1 year, except for CA certificates, which last 10 years.
To check expiration dates, run:
kubeadm certs check-expiration
🚨 If any certificates are close to expiring, renew them ASAP!
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