Change handler toleration to "operator: exists" (#755)

Since nmstate is to be used for configuration of the network
infrastructure, we want the handler to run on all nodes regardless
of taint. If a network config should not run on a given node, the
NNCP nodeSelector field can be used to accomplish that.

For example, a node with a taint of:

[map[effect:NoSchedule key:node.ocs.openshift.io/storage value:true]]

will currently keep the nmstate handler pod from running there.
However, that is not desirable since it prevents the use of nmstate
to configure networking on that storage node.

This changes the handler toleration to "operator: exists", which
will allow the handler to run on all nodes. The webhook toleration
is left alone since there is no need for that to be running on
nodes with a NoSchedule taint.

Signed-off-by: Ben Nemec <[email protected]>

controllers/nmstate_controller.go

@@ -154,6 +154,10 @@ func (r *NMStateReconciler) applyHandler(instance *nmstatev1beta1.NMState) error
 		Operator: corev1.TolerationOpExists,
 		Effect:   corev1.TaintEffectNoSchedule,
 	}
+	operatorExistsToleration := corev1.Toleration{
+		Key:      "",
+		Operator: corev1.TolerationOpExists,
+	}
 	amd64ArchOnMasterNodeSelector := map[string]string{
 		"beta.kubernetes.io/arch":        "amd64",
 		"node-role.kubernetes.io/master": "",
@@ -172,7 +176,7 @@ func (r *NMStateReconciler) applyHandler(instance *nmstatev1beta1.NMState) error
 	data.Data["WebhookTolerations"] = []corev1.Toleration{masterExistsNoScheduleToleration}
 	data.Data["WebhookAffinity"] = corev1.Affinity{}
 	data.Data["HandlerNodeSelector"] = amd64AndCRNodeSelector
-	data.Data["HandlerTolerations"] = []corev1.Toleration{masterExistsNoScheduleToleration}
+	data.Data["HandlerTolerations"] = []corev1.Toleration{operatorExistsToleration}
 	data.Data["HandlerAffinity"] = corev1.Affinity{}
 	// TODO: This is just a place holder to make template renderer happy
 	//       proper variable has to be read from env or CR