Add support for freeze in budgets

Provide a new API to freeze budgets and metrics to track its usage as API

DOC.md

@@ -94,6 +94,13 @@ ApplicationDisruptionBudgetSpec defines the desired state of ApplicationDisrupti
           A NodeDisruption is allowed if at most "maxDisruptions" nodes selected by selectors are unavailable after the disruption.<br/>
         </td>
         <td>true</td>
+      </tr><tr>
+        <td><b><a href="#applicationdisruptionbudgetspecfreeze">freeze</a></b></td>
+        <td>object</td>
+        <td>
+          Define the freeze status of the budget. Frozen budget reject all disruptions ignoring any other constraints<br/>
+        </td>
+        <td>false</td>
       </tr><tr>
         <td><b><a href="#applicationdisruptionbudgetspechealthhook">healthHook</a></b></td>
         <td>object</td>
@@ -121,6 +128,40 @@ Maintenance will proceed only if the endpoint responds 2XX.<br/>
 </table>
 
 
+### ApplicationDisruptionBudget.spec.freeze
+<sup><sup>[↩ Parent](#applicationdisruptionbudgetspec)</sup></sup>
+
+
+
+Define the freeze status of the budget. Frozen budget reject all disruptions ignoring any other constraints
+
+<table>
+    <thead>
+        <tr>
+            <th>Name</th>
+            <th>Type</th>
+            <th>Description</th>
+            <th>Required</th>
+        </tr>
+    </thead>
+    <tbody><tr>
+        <td><b>enabled</b></td>
+        <td>boolean</td>
+        <td>
+          Freeze the budget to prevent any disruptions<br/>
+        </td>
+        <td>false</td>
+      </tr><tr>
+        <td><b>reason</b></td>
+        <td>string</td>
+        <td>
+          Reason of the freeze<br/>
+        </td>
+        <td>false</td>
+      </tr></tbody>
+</table>
+
+
 ### ApplicationDisruptionBudget.spec.healthHook
 <sup><sup>[↩ Parent](#applicationdisruptionbudgetspec)</sup></sup>
 
@@ -492,6 +533,13 @@ NodeDisruptionBudgetSpec defines the desired state of NodeDisruptionBudget
           A NodeDisruption is allowed if at most "minUndisruptedNodes" nodes selected by selectors are unavailable after the disruption.<br/>
         </td>
         <td>true</td>
+      </tr><tr>
+        <td><b><a href="#nodedisruptionbudgetspecfreeze">freeze</a></b></td>
+        <td>object</td>
+        <td>
+          Define the freeze status of the budget. Frozen budget reject all disruptions ignoring any other constraints<br/>
+        </td>
+        <td>false</td>
       </tr><tr>
         <td><b><a href="#nodedisruptionbudgetspecnodeselector">nodeSelector</a></b></td>
         <td>object</td>
@@ -503,6 +551,40 @@ NodeDisruptionBudgetSpec defines the desired state of NodeDisruptionBudget
 </table>
 
 
+### NodeDisruptionBudget.spec.freeze
+<sup><sup>[↩ Parent](#nodedisruptionbudgetspec)</sup></sup>
+
+
+
+Define the freeze status of the budget. Frozen budget reject all disruptions ignoring any other constraints
+
+<table>
+    <thead>
+        <tr>
+            <th>Name</th>
+            <th>Type</th>
+            <th>Description</th>
+            <th>Required</th>
+        </tr>
+    </thead>
+    <tbody><tr>
+        <td><b>enabled</b></td>
+        <td>boolean</td>
+        <td>
+          Freeze the budget to prevent any disruptions<br/>
+        </td>
+        <td>false</td>
+      </tr><tr>
+        <td><b>reason</b></td>
+        <td>string</td>
+        <td>
+          Reason of the freeze<br/>
+        </td>
+        <td>false</td>
+      </tr></tbody>
+</table>
+
+
 ### NodeDisruptionBudget.spec.nodeSelector
 <sup><sup>[↩ Parent](#nodedisruptionbudgetspec)</sup></sup>
 

Makefile

@@ -75,7 +75,7 @@ test: manifests generate fmt vet envtest lint ## Run tests.
 ##@ Build
 
 .PHONY: build
-build: manifests generate fmt vet ## Build manager binary.
+build: manifests generate fmt vet gen-doc ## Build manager binary.
 	CGO_ENABLED=0 go build -o bin/manager cmd/main.go
 
 .PHONY: run

README.md

@@ -162,7 +162,6 @@ In some cases, an application can be unhealthy even if all its pods are running.
 
 You can select Pods and/or PVCs.
 
-
 ##### PVC selector
 
 The main reason of using a PVC selector is to ensure that node that contains data don't enter maintenance
@@ -182,6 +181,11 @@ The hook will be called with a POST method containing the JSON encoded NodeDisru
 
 Note: It is not a replacement for readiness probes but a complement.
 
+##### Freeze
+
+Budgets support freezing disruptions. By setting `spec.Freeze.Enabled`, the budget will reject all disruptions and give the reason specified in `spec.Freeze.Reason`. 
+It is equivalent to setting 0 as the max disruptions but it provide better messages.
+
 #### Sample object
 
 ```yaml

api/v1alpha1/applicationdisruptionbudget_types.go

@@ -43,6 +43,16 @@ type ApplicationDisruptionBudgetSpec struct {
 	// Maintenance will proceed only if the endpoint responds 2XX.
 	// +kubebuilder:validation:Optional
 	HealthHook HealthHookSpec `json:"healthHook,omitempty"`
+	// Define the freeze status of the budget. Frozen budget reject all disruptions ignoring any other constraints
+	Freeze FreezeSpec `json:"freeze,omitempty"`
+}
+
+// FreezeSpec defines the freeze status of the budget
+type FreezeSpec struct {
+	// Freeze the budget to prevent any disruptions
+	Enabled bool `json:"enabled,omitempty"`
+	// Reason of the freeze
+	Reason string `json:"reason,omitempty"`
 }
 
 type HealthHookSpec struct {

api/v1alpha1/nodedisruptionbudget_types.go

@@ -37,6 +37,8 @@ type NodeDisruptionBudgetSpec struct {
 	MinUndisruptedNodes int `json:"minUndisruptedNodes"`
 	// NodeSelector query over pods whose nodes are managed by the disruption budget.
 	NodeSelector metav1.LabelSelector `json:"nodeSelector,omitempty"`
+	// Define the freeze status of the budget. Frozen budget reject all disruptions ignoring any other constraints
+	Freeze FreezeSpec `json:"freeze,omitempty"`
 }
 
 //+kubebuilder:object:root=true

chart/templates/applicationdisruptionbudget-crd.yaml

@@ -54,6 +54,17 @@ spec:
             description: ApplicationDisruptionBudgetSpec defines the desired state of
               ApplicationDisruptionBudget
             properties:
+              freeze:
+                description: Define the freeze status of the budget. Frozen budget reject
+                  all disruptions ignoring any other constraints
+                properties:
+                  enabled:
+                    description: Freeze the budget to prevent any disruptions
+                    type: boolean
+                  reason:
+                    description: Reason of the freeze
+                    type: string
+                type: object
               healthHook:
                 description: |-
                   Define a optional hook to call when validating a NodeDisruption.

chart/templates/nodedisruptionbudget-crd.yaml

@@ -56,6 +56,17 @@ spec:
           spec:
             description: NodeDisruptionBudgetSpec defines the desired state of NodeDisruptionBudget
             properties:
+              freeze:
+                description: Define the freeze status of the budget. Frozen budget reject
+                  all disruptions ignoring any other constraints
+                properties:
+                  enabled:
+                    description: Freeze the budget to prevent any disruptions
+                    type: boolean
+                  reason:
+                    description: Reason of the freeze
+                    type: string
+                type: object
               maxDisruptedNodes:
                 description: A NodeDisruption is allowed if at most "maxDisruptedNodes"
                   nodes selected by selectors are unavailable after the disruption.

config/crd/bases/nodedisruption.criteo.com_applicationdisruptionbudgets.yaml

@@ -53,6 +53,17 @@ spec:
             description: ApplicationDisruptionBudgetSpec defines the desired state
               of ApplicationDisruptionBudget
             properties:
+              freeze:
+                description: Define the freeze status of the budget. Frozen budget
+                  reject all disruptions ignoring any other constraints
+                properties:
+                  enabled:
+                    description: Freeze the budget to prevent any disruptions
+                    type: boolean
+                  reason:
+                    description: Reason of the freeze
+                    type: string
+                type: object
               healthHook:
                 description: |-
                   Define a optional hook to call when validating a NodeDisruption.

config/crd/bases/nodedisruption.criteo.com_nodedisruptionbudgets.yaml

@@ -55,6 +55,17 @@ spec:
           spec:
             description: NodeDisruptionBudgetSpec defines the desired state of NodeDisruptionBudget
             properties:
+              freeze:
+                description: Define the freeze status of the budget. Frozen budget
+                  reject all disruptions ignoring any other constraints
+                properties:
+                  enabled:
+                    description: Freeze the budget to prevent any disruptions
+                    type: boolean
+                  reason:
+                    description: Reason of the freeze
+                    type: string
+                type: object
               maxDisruptedNodes:
                 description: A NodeDisruption is allowed if at most "maxDisruptedNodes"
                   nodes selected by selectors are unavailable after the disruption.

internal/controller/applicationdisruptionbudget_controller.go

@@ -115,6 +115,12 @@ func PruneADBMetrics(ref nodedisruptionv1alpha1.NamespacedName) {
 // UpdateADBMetrics update metrics for an ADB
 func UpdateADBMetrics(ref nodedisruptionv1alpha1.NamespacedName, adb *nodedisruptionv1alpha1.ApplicationDisruptionBudget) {
 	DisruptionBudgetMaxDisruptions.WithLabelValues(ref.Namespace, ref.Name, ref.Kind).Set(float64(adb.Spec.MaxDisruptions))
+	if adb.Spec.Freeze.Enabled {
+		DisruptionBudgetFrozen.WithLabelValues(ref.Namespace, ref.Name, ref.Kind).Set(1)
+	} else {
+		DisruptionBudgetFrozen.WithLabelValues(ref.Namespace, ref.Name, ref.Kind).Set(0)
+	}
+
 	UpdateBudgetStatusMetrics(ref, adb.Status)
 }
 
@@ -200,6 +206,14 @@ func (r *ApplicationDisruptionBudgetResolver) IsImpacted(disruptedNodes resolver
 
 // Return the number of disruption allowed considering a list of current node disruptions
 func (r *ApplicationDisruptionBudgetResolver) TryValidateDisruptionFromBudgetConstraints(_ resolver.NodeSet) nodedisruptionv1alpha1.DisruptedBudgetStatus {
+	if r.ApplicationDisruptionBudget.Spec.Freeze.Enabled {
+		return nodedisruptionv1alpha1.DisruptedBudgetStatus{
+			Reference: r.GetNamespacedName(),
+			Reason:    fmt.Sprintf("Budget frozen: %s", r.ApplicationDisruptionBudget.Spec.Freeze.Reason),
+			Ok:        false,
+		}
+	}
+
 	if r.ApplicationDisruptionBudget.Status.DisruptionsAllowed-1 >= 0 {
 		return nodedisruptionv1alpha1.DisruptedBudgetStatus{
 			Reference: r.GetNamespacedName(),

internal/controller/metrics.go

@@ -139,4 +139,11 @@ var (
 		},
 		[]string{"disruption_budget_namespace", "disruption_budget_name", "disruption_budget_kind", "node_disruption_name"},
 	)
+	DisruptionBudgetFrozen = promauto.With(metrics.Registry).NewGaugeVec(
+		prometheus.GaugeOpts{
+			Name: METIC_PREFIX + "budget_disruption_frozen",
+			Help: "Budget frozen",
+		},
+		[]string{"disruption_budget_namespace", "disruption_budget_name", "disruption_budget_kind"},
+	)
 )