cluster-autoscaler-operator

README

Cluster Autoscaler Operator

The cluster-autoscaler-operator manages deployments of the OpenShift Cluster Autoscaler using the cluster-api provider.

Custom Resource Definitions

The operator manages the following custom resources:

• ClusterAutoscaler: This is a singleton resource which controls the configuration of the cluster's autoscaler instance. The operator will only respond to the ClusterAutoscaler resource named "default" in the managed namespace, i.e. the value of the WATCH_NAMESPACE environment variable. (Example)

  The fields in the spec for ClusterAutoscaler resources correspond to command-line arguments to the cluster-autoscaler. The example linked above results in the following invocation:

    Command:
      cluster-autoscaler
    Args:
      --logtostderr
      --cloud-provider=cluster-api
      --namespace=openshift-cluster-api
      --expendable-pods-priority-cutoff=-10
      --max-nodes-total=24
      --cores-total=8:128
      --memory-total=4:256
      --gpu-total=nvidia.com/gpu:0:16
      --gpu-total=amd.com/gpu:0:4
      --scale-down-enabled=true
      --scale-down-delay-after-add=10s
      --scale-down-delay-after-delete=10s
      --scale-down-delay-after-failure=10s
  

• MachineAutoscaler: This resource targets a node group and manages the annotations to enable and configure autoscaling for that group, e.g. the min and max size. Currently only MachineSet objects can be targeted. (Example)

Development

## Build, Test, & Run
$ make build
$ make test

$ export WATCH_NAMESPACE=openshift-cluster-api
$ ./bin/cluster-autoscaler-operator -alsologtostderr

The Cluster Autoscaler Operator is designed to be deployed on OpenShift by the Cluster Version Operator, but it's possible to run it directly on any vanilla Kubernetes cluster that has the cluster-api components available. To do so, apply the manifests in the install directory: kubectl apply -f ./install

This will create the openshift-cluster-api namespace, register the custom resource definitions, configure RBAC policies, and create a deployment for the operator.

End-to-End Tests

You can run the e2e test suite with make test-e2e. These tests assume the presence of a cluster not already running the operator, and that the KUBECONFIG environment variable points to a configuration granting admin rights on said cluster.