Fix: Encryption Secret Causes Cluster Creation To Hang

Nov 28, 2025 by Alex Johnson 55 views

Have you ever encountered a situation where your cluster creation gets stuck, leaving you wondering what went wrong? One common culprit in Kubermatic deployments is an issue with Encryption at Rest (EAR) secrets. This article dives deep into a specific scenario where creating a cluster with EAR enabled can lead to a frustrating hang, and more importantly, how to resolve it. We'll explore the root cause, expected behavior, reproduction steps, and a practical workaround to get your cluster creation back on track.

Understanding the Encryption at Rest Secret Issue

When dealing with Encryption at Rest (EAR) in Kubermatic, the proper placement of encryption secrets is paramount for successful cluster creation. The core issue arises when the encryption secret, intended to protect sensitive data within the cluster, is mistakenly created in the wrong location. Specifically, if you're using separate master and seed clusters and enable EAR via the API or UI, the encryption secret might be created in the seed cluster's kubermatic namespace. This is problematic because, in shared environments, the seed cluster often lacks this namespace.

This misplacement has a domino effect. The cluster creation process becomes stuck in the Creating phase, and the encryption-secret-synchronizer controller, responsible for ensuring the secret's presence, keeps looking for it in the master cluster's kubermatic namespace – where it should have been created in the first place. This constant search without success leads to the cluster hanging indefinitely, preventing you from accessing and utilizing your new cluster. Therefore, understanding the intricacies of Encryption at Rest (EAR) and its secret management is crucial for a smooth cluster deployment process. The key takeaway is that the encryption secret needs to reside in the master cluster's kubermatic namespace for the synchronization process to work correctly. Addressing this misplacement promptly is essential to avoid the frustrating hang and ensure successful cluster creation.

Expected Behavior: Where the Secret Should Reside

To fully grasp the issue, let's clarify the expected behavior regarding Encryption at Rest (EAR) secrets. When you enable EAR during cluster creation, the encryption secret should be created in a very specific location: the kubermatic namespace within the master cluster. This is the designated place where the encryption-secret-synchronizer controller expects to find the secret. Once the secret is present in the master cluster's kubermatic namespace, the encryption secret synchronizer takes over. This crucial component is designed to then synchronize the secret to the appropriate seed cluster. This synchronization process ensures that the seed cluster has the necessary information to properly encrypt data at rest.

In essence, the master cluster acts as the central repository for the encryption secret, and the synchronizer acts as the distribution mechanism. This design ensures consistency and proper security across your Kubermatic environment. The correct placement of the encryption secret is not just a matter of convention; it's a fundamental requirement for the entire EAR mechanism to function correctly. When the secret is created in the wrong location, such as the seed cluster's namespace, the synchronizer cannot find it, leading to the cluster creation hang we discussed earlier. Therefore, understanding this expected behavior is key to both preventing and resolving issues related to EAR and cluster creation. Always ensure that the initial encryption secret resides in the master cluster's kubermatic namespace to avoid these pitfalls.

Reproducing the Issue: A Step-by-Step Guide

If you're encountering cluster creation hangs and suspect an Encryption at Rest (EAR) secret issue, it's helpful to reproduce the problem in a controlled environment. This allows you to confirm the root cause and test potential solutions. Here's a step-by-step guide to reproduce the issue:

Deploy Kubermatic with Separate Master and Seed Clusters: This setup is crucial for triggering the specific issue we're addressing. Ensure that your Kubermatic deployment consists of distinct master and seed clusters. This separation is a common architecture in many Kubermatic environments and is where the misplacement of the encryption secret becomes a concern.
Create a New User Cluster with EAR Enabled: This is the key step that initiates the problem. When creating a new user cluster, either through the Kubermatic API or the UI dashboard, explicitly enable the Encryption at Rest feature. This signals to Kubermatic that data encryption should be implemented for the new cluster.
Observe the Cluster Stuck in the Creating Phase: After initiating the cluster creation with EAR enabled, monitor the progress. If the encryption secret is created in the wrong location, you'll likely observe the cluster becoming stuck in the Creating phase. The creation process will appear to be indefinitely stalled, and you won't be able to proceed with using the cluster. This is a strong indicator that the EAR secret issue is the culprit.

By following these steps, you can reliably reproduce the issue and confirm whether the encryption secret misplacement is the reason for your cluster creation hang. Once reproduced, you can then proceed with the workaround described in the next section to resolve the problem.

Current Workaround: Manual Secret Creation

Fortunately, there's a straightforward workaround to address the Encryption at Rest (EAR) secret issue and get your cluster creation unstuck. The solution involves manually creating the encryption secret in the correct location: the master cluster's kubermatic namespace. This manual intervention bypasses the incorrect automated creation and places the secret where the encryption-secret-synchronizer controller expects it to be.

To implement this workaround, you'll need to access your master cluster and use kubectl, the Kubernetes command-line tool. The exact steps for creating the secret will depend on your specific setup and the requirements of your EAR configuration. However, the general process involves generating an appropriate secret manifest (usually in YAML format) and then applying it to the master cluster within the kubermatic namespace.

Here's a general outline of the steps:

Access the Master Cluster: Ensure you have kubectl configured to connect to your master cluster.
Generate the Encryption Secret Manifest: Create a YAML file that defines the encryption secret. This manifest should specify the secret's name, namespace (kubermatic), and the encryption key itself. The key generation process will depend on your chosen encryption method.
Apply the Manifest: Use kubectl apply -f <your-secret-manifest.yaml> to create the secret in the master cluster's kubermatic namespace.

Once you've manually created the secret in the correct location, the encryption-secret-synchronizer should be able to find it and proceed with synchronizing it to the seed cluster. This should unblock the cluster creation process, allowing it to complete successfully. While this workaround resolves the immediate issue, it's important to note that it's a manual step. Ideally, the secret creation should be automated and placed in the correct location by default. This highlights the importance of addressing the underlying bug that causes the initial misplacement.

Conclusion

In conclusion, encountering a cluster creation hang due to misplaced Encryption at Rest (EAR) secrets can be a frustrating experience. However, understanding the root cause – the incorrect creation of the encryption secret in the seed cluster's namespace instead of the master cluster's kubermatic namespace – is the first step towards resolution. By recognizing the expected behavior, where the secret should reside in the master cluster, and following the provided workaround of manually creating the secret in the correct location, you can effectively unblock the cluster creation process.

Remember, the key takeaway is that the encryption-secret-synchronizer controller relies on the secret being present in the master cluster's kubermatic namespace for proper synchronization. While the manual workaround provides an immediate solution, it's crucial to address the underlying issue to prevent future occurrences. This might involve reporting the bug to the Kubermatic team or implementing automation to ensure correct secret placement during cluster creation.

By proactively addressing this EAR secret issue, you can ensure smoother cluster deployments and maintain the security of your data at rest. Always double-check the location of your encryption secrets, especially when using separate master and seed clusters, to avoid the pitfall of a hanging cluster creation. For more in-depth information about Kubermatic and best practices for cluster management, consider exploring resources like the official Kubermatic Documentation.