Add possibility to set Jenkins master pod's priority

Allow to set priorityClassName for master pod. This will make possible
for jenkins master to either not be preempted on other's pod low
resources or to preempt lesser priority pods on resources shortage.

Ref: https://github.com/jenkinsci/kubernetes-operator/issues/321

pkg/apis/jenkins/v1alpha2/jenkins_types.go

@@ -374,6 +374,10 @@ type JenkinsMaster struct {
 
 	// DisableCSRFProtection allows you to toggle CSRF Protection on Jenkins
 	DisableCSRFProtection bool `json:"disableCSRFProtection"`
+
+	// PriorityClassName for Jenkins master pod
+	// +optional
+	PriorityClassName string `json:"priorityClassName,omitempty"`
 }
 
 // Service defines Kubernetes service attributes

pkg/controller/jenkins/configuration/base/reconcile.go

@@ -648,6 +648,12 @@ func (r *ReconcileJenkinsBaseConfiguration) checkForPodRecreation(currentJenkins
 			len(currentJenkinsMasterPod.Spec.Containers), len(r.Configuration.Jenkins.Spec.Master.Containers)))
 	}
 
+	if r.Configuration.Jenkins.Spec.Master.PriorityClassName != currentJenkinsMasterPod.Spec.PriorityClassName {
+		messages = append(messages, "Jenkins priorityClassName has changed")
+		verbose = append(verbose, fmt.Sprintf("Jenkins priorityClassName has changed, actual '%+v' required '%+v'",
+			currentJenkinsMasterPod.Spec.PriorityClassName, r.Configuration.Jenkins.Spec.Master.PriorityClassName))
+	}
+
 	customResourceReplaced := (r.Configuration.Jenkins.Status.BaseConfigurationCompletedTime == nil ||
 		r.Configuration.Jenkins.Status.UserConfigurationCompletedTime == nil) &&
 		r.Configuration.Jenkins.Status.UserAndPasswordHash == ""

pkg/controller/jenkins/configuration/base/resources/pod.go

@@ -328,6 +328,7 @@ func NewJenkinsMasterPod(objectMeta metav1.ObjectMeta, jenkins *v1alpha2.Jenkins
 			SecurityContext:    jenkins.Spec.Master.SecurityContext,
 			ImagePullSecrets:   jenkins.Spec.Master.ImagePullSecrets,
 			Tolerations:        jenkins.Spec.Master.Tolerations,
+			PriorityClassName:  jenkins.Spec.Master.PriorityClassName,
 		},
 	}
 }