/machine-api-operator

Machine API operator

Primary LanguageGoApache License 2.0Apache-2.0

Machine API Operator

The Machine API Operator manages the lifecycle of specific purpose CRDs, controllers and RBAC objects that extend the Kubernetes API. This allows to convey desired state of machines in a cluster in a declarative fashion.

Architecture

Machine API Operator overview

CRDs

  • MachineSet
  • Machine
  • Cluster
  • MachineHealthCheck

Controllers

Cluster API controllers

Nodelink controller

  • Reconciles desired state of machines by matching IP addresses of machine objects with IP addresses of node objects and annotates nodes with a special machine annotation containing the machine name. The cluster-api node controller interprets the annotation and sets the corresponding nodeRef field of each relevant machine.

  • Build:

$ make nodelink-controller

Machine healthcheck controller

  • Reconciles desired state for MachineHealthChecks by ensuring that machines targeted by machineHealthCheck objects are healthy or remediated otherwise.

  • Build:

    $ make machine-healthcheck

  • How to test it:

    1. Create a machineset and locate its selector. Assuming the selector corresponds to the following list of match labels:

      machine.openshift.io/cluster-api-cluster: cluster
machine.openshift.io/cluster-api-machine-role: worker
machine.openshift.io/cluster-api-machine-type: worker
machine.openshift.io/cluster-api-machineset: cluster-worker-us-east-1a

    2. Define a MachineHealthCheck manifest that will be watching all machines of the machinset based on its match labels:

      apiVersion: healthchecking.openshift.io/v1alpha1
kind: MachineHealthCheck
metadata:
  name: example
  namespace: default
spec:
  selector:
    matchLabels:
      machine.openshift.io/cluster-api-cluster: cluster
      machine.openshift.io/cluster-api-machine-role: worker
      machine.openshift.io/cluster-api-machine-type: worker
      machine.openshift.io/cluster-api-machineset: cluster-worker-us-east-1a

    3. By default, the machine health check controller recognize only NotReady condition and will remove unhealthy machine after 5 minutes. If you want to customize unhealthy conditions you can create node-unhealthy-conditions config map, for example:

      apiVersion: v1
kind: ConfigMap
metadata:
  name: node-unhealthy-conditions
  namespace: openshift-machine-api
data:
  conditions: |
    items:
    - name: NetworkUnavailable
      timeout: 5m
      status: True

    4. Pick a node that is managed by one of the machineset's machines

    5. SSH into the node, disable and stop the kubelet services:

      # systemctl disable kubelet
# systemctl stop kubelet

    6. After some time the node will transition into NotReady state

    7. Watch the machine-healthcheck controller logs to see how it notices a node in NotReady state and starts to reconcile the node

    8. After some time the current node instance is terminated and new instance is created. Followed by new node joining the cluster and turning in Ready state.

Creating machines

You can create a new machine by applying a manifest representing an instance of the machine CRD

The machine.openshift.io/cluster-api-cluster label will be used by the controllers to lookup for the right cloud instance.

You can set other labels to provide a convenient way for users and consumers to retrieve groups of machines:

machine.openshift.io/cluster-api-machine-role: worker
machine.openshift.io/cluster-api-machine-type: worker

Dev

  • Generate code (if needed):

    $ make generate

  • Build:

    $ make build

  • Run:

    $ ./bin/machine-api-operator start --kubeconfig ${HOME}/.kube/config --images-json=pkg/operator/fixtures/images.json

  • Image:

    $ make image

The Machine API Operator is designed to work in conjunction with the Cluster Version Operator. You can see it in action by running an OpenShift Cluster deployed by the Installer.

However you can run it in a vanilla Kubernetes cluster by precreating some assets:

Machine API operator with Kubemark over Kubernetes

INFO: For development and testing purposes only

  1. Deploy MAO over Kubernetes:
 $ kustomize build | kubectl apply -f -

  1. Deploy Kubemark actuator prerequisities:

    $ kustomize build config | kubectl apply -f -

  2. Create cluster infrastructure.config.openshift.io to tell the MAO to deploy kubemark provider:

    apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: infrastructures.config.openshift.io
spec:
  group: config.openshift.io
  names:
    kind: Infrastructure
    listKind: InfrastructureList
    plural: infrastructures
    singular: infrastructure
  scope: Cluster
  versions:
  - name: v1
    served: true
storage: true
---
apiVersion: config.openshift.io/v1
kind: Infrastructure
metadata:
  name: cluster
status:
  platform: kubemark

    The file is already present under config/kubemark-config-infra.yaml so it's sufficient to run:

    $ kubectl apply -f config/kubemark-config-infra.yaml

CI & tests

Run unit test:

$ make test

Run e2e-aws-operator tests. This tests assume that a cluster deployed by the Installer is up and running and a KUBECONFIG environment variable is set:

$ make test-e2e

Tests are located under machine-api-operator repository and executed in prow CI system. A link to failing tests is published as a comment in PR by @openshift-ci-robot. Current test status for all OpenShift components can be found in https://deck-ci.svc.ci.openshift.org.

CI configuration is stored under openshift/release repository and is split into 4 files:

More information about those files can be found in ci-operator onboarding file.