Establishing Connection between Kubeseal and Kubernetes Cluster⚓︎

This article explains how to connect Kubeseal to a Kubernetes cluster for sealing secrets.

Before you can start sealing secrets, the Kubeseal CLI must retrieve the public key from the Sealed Secrets controller running in your cluster. This key allows Kubeseal to encrypt secrets so that only the controller can decrypt them.

1. Verify Your Cluster Is Running⚓︎

First, ensure your Kubernetes cluster is healthy by listing all pods in the kube-system namespace:

kubectl get pods -n kube-system

You should see output similar to:

NAME                                          READY   STATUS    RESTARTS   AGE
coredns-5d78c9869d-wm8sw                      1/1     Running   0          13h
etcd-minikube                                 1/1     Running   0          13h
kube-apiserver-minikube                       1/1     Running   0          13h
kube-controller-manager-minikube              1/1     Running   0          13h
kube-proxy-x6f9j                              1/1     Running   0          13h
kube-scheduler-minikube                       1/1     Running   0          13h
my-release-sealed-secrets-76b49fc554-wk717    1/1     Running   0          21s
storage-provisioner                           1/1     Running   0          13h

Note

If any core component is not Running, troubleshoot using kubectl describe pod <pod-name> -n kube-system or check your cluster’s control-plane logs.

2. Attempt to Fetch the Public Certificate⚓︎

Run the following command to fetch the controller’s public certificate. This step fails initially because Kubeseal doesn’t know which controller service to target:

kubeseal --fetch-cert

Expected error:

error: cannot get sealed secret service: services "sealed-secrets-controller" not found
Please, use the flag --controller-name and --controller-namespace to set up the name and namespace of the sealed secrets controller

3. Discover the Sealed Secrets Service⚓︎

Identify the actual service name and namespace by listing services in kube-system:

kubectl get svc -n kube-system

Example output:

NAME                          TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)    AGE
kube-dns                      ClusterIP   10.96.0.10     <none>        53/UDP     13h
my-release-sealed-secrets     ClusterIP   10.97.19.137   <none>        8080/TCP   3m25s

From this list, note:

Service Name: my-release-sealed-secrets
Namespace: kube-system

4. Fetch and Save the Public Key⚓︎

With the service details in hand, re-run the fetch command with the appropriate flags:

kubeseal --fetch-cert \
  --controller-name      my-release-sealed-secrets \
  --controller-namespace kube-system \
  > pub-cert.pem

If this completes without errors, you now have pub-cert.pem containing the Sealed Secrets controller’s public key.

Note

You’re ready to use kubeseal with --cert pub-cert.pem to encrypt your Kubernetes Secrets. Learn more in the Sealed Secrets documentation.

Quick Reference Table⚓︎

Step	Command	Purpose
Check cluster pods	`kubectl get pods -n kube-system`	Verify core components and Sealed Secrets pod state
List services	`kubectl get svc -n kube-system`	Discover the Sealed Secrets service name
Fetch controller certificate	`kubeseal --fetch-cert --controller-name …`	Retrieve public key for encrypting secrets