The Kubernetes Controller Manager operator manages and updates the Kubernetes Controller Manager deployed on top of OpenShift. The operator is based on OpenShift library-go framework and it is installed via Cluster Version Operator (CVO).
It contains the following components:
- Operator
- Bootstrap manifest renderer
- Installer based on static pods
- Configuration observer
By default, the operator exposes Prometheus metrics via metrics service.
The metrics are collected from following components:
- Kubernetes Controller Manager operator
The configuration for the Kubernetes Controller Manager is coming from:
Operator also expose events that can help debugging issues. To get operator events, run following command:
$ oc get events -n openshift-kube-controller-manager-operator
This operator is configured via KubeControllerManager custom resource:
$ oc describe kubecontrollermanager
apiVersion: operator.openshift.io/v1
kind: KubeControllerManager
metadata:
name: cluster
spec:
managementState: Managed
...$ oc explain kubecontrollermanager
to learn more about the resource itself.
The current operator status is reported using the ClusterOperator resource. To get the current status you can run follow command:
$ oc get clusteroperator/kube-controller-manager
In the running cluster cluster-version-operator is responsible for maintaining functioning and non-altered elements. In that case to be able to use custom operator image one has to perform one of these operations:
- Set your operator in umanaged state, see here for details, in short:
oc patch clusterversion/version --type='merge' -p "$(cat <<- EOF
spec:
overrides:
- group: apps
kind: Deployment
name: kube-controller-manager-operator
namespace: openshift-kube-controller-manager-operator
unmanaged: true
EOF
)"
- Scale down cluster-version-operator:
oc scale --replicas=0 deploy/cluster-version-operator -n openshift-cluster-version
IMPORTANT: This apprach disables cluster-version-operator completly, whereas previous only tells it to not manage a kube-controller-manager-operator!
After doing this you can now change the image of the operator to the desired one:
oc patch deployment/kube-controller-manager-operator -n openshift-kube-controller-manager-operator -p '{"spec":{"template":{"spec":{"containers":[{"name":"kube-controller-manager-operator","image":"<user>/cluster-kube-controller-manager-operator","env":[{"name":"OPERATOR_IMAGE","value":"<user>/cluster-kube-controller-manager-operator"}]}]}}}}'
The operator image version used by the installer bootstrap phase can be overridden by creating a custom origin-release image pointing to the developer's operator :latest image:
$ IMAGE_ORG=<user> make images
$ docker push <user>/origin-cluster-kube-controller-manager-operator
$ cd ../cluster-kube-apiserver-operator
$ IMAGES=cluster-kube-controller-manager-operator IMAGE_ORG=<user> make origin-release
$ docker push <user>/origin-release:latest
$ cd ../installer
$ OPENSHIFT_INSTALL_RELEASE_IMAGE_OVERRIDE=docker.io/<user>/origin-release:latest bin/openshift-install cluster ...