Kairos Operator

⚠️ WARNING: This operator is currently a work in progress and not ready for production use. Until it's ready for consumption, this README won't always reflect the current state of things.

Implementation Plan (TODO list)

• Deploy a DaemonSet (KairosNodeStatus) on all nodes.

  • Mount /etc/kairos-release and /etc/os-release using hostPath.
  • Detect if the node is Kairos-based.
  • If so, create or update a KairosNode CR named after the node.
  • Only update the status field (e.g., observedVersion, cloudConfigHash, upgradeState).

• Define a KairosNode CRD:

  • .spec: desired version, active/recovery images, config hash, etc.
  • .status: current version, upgrade progress, timestamps.

• The Operator:

  • Watches KairosNode resources.
  • Compares spec.version vs status.observedVersion.
  • Triggers an upgrade Job when needed and upgradeState != InProgress.
  • The Job:
    • Drains the node (excluding upgrade and status Pods).
    • Performs upgrade and reboots the node.
    • Optionally uncordons the node.

• After reboot, the DaemonSet resumes and updates KairosNode.status.

• Operator detects successful upgrade and marks the state as Completed.

---

🔐 Security & Permissions

• DaemonSet Pods:

  • Run unprivileged.
  • Mount only required files (hostPath: /etc/kairos-release, etc).
  • Use a dedicated ServiceAccount with RBAC:

    apiGroups: ["kairos.io"]
    resources: ["kairosnodes/status"]
    verbs: ["get", "patch", "update"]

• Use projected service account tokens with:

  • Short expiration (e.g., 600s)
  • Custom audience (e.g., kairos-operator)

---

🧠 Behavioral Logic

• DaemonSet creates CRs only for Kairos nodes (detected via /etc/os-release).
• KairosNode.status.upgradeState acts as a state machine:
  • Idle → InProgress → Completed
• Node is uncordoned by:
  • Upgrade Job (preferred), or
  • Operator after detecting version match.

---

📌 Notes

• Do not create KairosNode for non-Kairos nodes.
• Operator does not update built-in Node resources.
• Optional: label Kairos nodes for visibility:

  labels:
    kairos.io/managed: "true"
  
  

Getting Started

Prerequisites

• go version v1.23.0+
• docker version 17.03+.
• kubectl version v1.11.3+.
• Access to a Kubernetes v1.11.3+ cluster.

To Deploy on the cluster

Build and push your image to the location specified by IMG:

make docker-build docker-push IMG=<some-registry>/operator:tag

NOTE: This image ought to be published in the personal registry you specified. And it is required to have access to pull the image from the working environment. Make sure you have the proper permission to the registry if the above commands don't work.

Install the CRDs into the cluster:

make install

Deploy the Manager to the cluster with the image specified by IMG:

make deploy IMG=<some-registry>/operator:tag

NOTE: If you encounter RBAC errors, you may need to grant yourself cluster-admin privileges or be logged in as admin.

Create instances of your solution You can apply the samples (examples) from the config/sample:

kubectl apply -k config/samples/

NOTE: Ensure that the samples has default values to test it out.

To Uninstall

Delete the instances (CRs) from the cluster:

kubectl delete -k config/samples/

Delete the APIs(CRDs) from the cluster:

make uninstall

UnDeploy the controller from the cluster:

make undeploy

Project Distribution

Following the options to release and provide this solution to the users.

By providing a bundle with all YAML files

1. Build the installer for the image built and published in the registry:

make build-installer IMG=<some-registry>/operator:tag

NOTE: The makefile target mentioned above generates an 'install.yaml' file in the dist directory. This file contains all the resources built with Kustomize, which are necessary to install this project without its dependencies.

2. Using the installer

Users can just run 'kubectl apply -f ' to install the project, i.e.:

kubectl apply -f https://raw.githubusercontent.com/<org>/operator/<tag or branch>/dist/install.yaml

By providing a Helm Chart

1. Build the chart using the optional helm plugin

kubebuilder edit --plugins=helm/v1-alpha

2. See that a chart was generated under 'dist/chart', and users can obtain this solution from there.

NOTE: If you change the project, you need to update the Helm Chart using the same command above to sync the latest changes. Furthermore, if you create webhooks, you need to use the above command with the '--force' flag and manually ensure that any custom configuration previously added to 'dist/chart/values.yaml' or 'dist/chart/manager/manager.yaml' is manually re-applied afterwards.

Contributing

// TODO(user): Add detailed information on how you would like others to contribute to this project

NOTE: Run make help for more information on all potential make targets

More information can be found via the Kubebuilder Documentation

License

Copyright 2025.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.