Implement in-place Pod image update

operator/api/core/v1alpha1/crds/grove.io_podcliquesets.yaml

@@ -10776,6 +10776,17 @@ spec:
                   templates change. This applies to both standalone PodCliques and
                   PodCliqueScalingGroups.
                 properties:
+                  inPlaceUpdate:
+                    description: InPlaceUpdate configures behavior for in-place update
+                      strategies.
+                    properties:
+                      gracePeriodSeconds:
+                        description: |-
+                          GracePeriodSeconds is the delay between marking a Pod not ready through the
+                          Grove in-place readiness gate and patching container images.
+                        format: int32
+                        type: integer
+                    type: object
                   type:
                     default: RollingRecreate
                     description: |-
@@ -10786,6 +10797,8 @@ spec:
                     enum:
                     - RollingRecreate
                     - OnDelete
+                    - InPlaceIfPossible
+                    - InPlaceOnly
                     type: string
                 type: object
             required:

operator/api/core/v1alpha1/podcliqueset.go

@@ -112,6 +112,17 @@ type PodCliqueSetUpdateStrategy struct {
 	// Default is RollingRecreate.
 	// +kubebuilder:default=RollingRecreate
 	Type UpdateStrategyType `json:"type,omitempty"`
+	// InPlaceUpdate configures behavior for in-place update strategies.
+	// +optional
+	InPlaceUpdate *InPlaceUpdateStrategy `json:"inPlaceUpdate,omitempty"`
+}
+
+// InPlaceUpdateStrategy defines settings for in-place Pod image updates.
+type InPlaceUpdateStrategy struct {
+	// GracePeriodSeconds is the delay between marking a Pod not ready through the
+	// Grove in-place readiness gate and patching container images.
+	// +optional
+	GracePeriodSeconds *int32 `json:"gracePeriodSeconds,omitempty"`
 }
 
 // PodCliqueSetRollingUpdateProgress captures the progress of a rolling update of the PodCliqueSet.
@@ -424,7 +435,7 @@ type HeadlessServiceConfig struct {
 }
 
 // UpdateStrategyType defines the type of update strategy for PodCliqueSet.
-// +kubebuilder:validation:Enum={RollingRecreate,OnDelete}
+// +kubebuilder:validation:Enum={RollingRecreate,OnDelete,InPlaceIfPossible,InPlaceOnly}
 type UpdateStrategyType string
 
 const (
@@ -439,6 +450,13 @@ const (
 	// they are manually deleted. Changes to templates do not automatically
 	// trigger replica deletions.
 	OnDeleteStrategy UpdateStrategyType = "OnDelete"
+	// InPlaceIfPossibleStrategy indicates that Pods should be updated in-place
+	// when their changes are eligible for in-place update. Unsupported changes
+	// fall back to RollingRecreate.
+	InPlaceIfPossibleStrategy UpdateStrategyType = "InPlaceIfPossible"
+	// InPlaceOnlyStrategy indicates that Pods should only be updated in-place.
+	// Unsupported changes block the update instead of deleting Pods.
+	InPlaceOnlyStrategy UpdateStrategyType = "InPlaceOnly"
 )
 
 // CliqueStartupType defines the order in which each PodClique is started.

operator/internal/controller/common/component/utils/podcliqueset.go

@@ -121,6 +121,23 @@ func IsAutoUpdateStrategy(pcs *grovecorev1alpha1.PodCliqueSet) bool {
 	return pcs.Spec.UpdateStrategy == nil || pcs.Spec.UpdateStrategy.Type != grovecorev1alpha1.OnDeleteStrategy
 }
 
+// IsInPlaceUpdateStrategy returns true when PodCliqueSet update strategy should attempt in-place Pod image updates.
+func IsInPlaceUpdateStrategy(pcs *grovecorev1alpha1.PodCliqueSet) bool {
+	if pcs == nil || pcs.Spec.UpdateStrategy == nil {
+		return false
+	}
+	return pcs.Spec.UpdateStrategy.Type == grovecorev1alpha1.InPlaceIfPossibleStrategy ||
+		pcs.Spec.UpdateStrategy.Type == grovecorev1alpha1.InPlaceOnlyStrategy
+}
+
+// IsInPlaceOnlyStrategy returns true when unsupported in-place changes should block instead of falling back to recreate.
+func IsInPlaceOnlyStrategy(pcs *grovecorev1alpha1.PodCliqueSet) bool {
+	if pcs == nil || pcs.Spec.UpdateStrategy == nil {
+		return false
+	}
+	return pcs.Spec.UpdateStrategy.Type == grovecorev1alpha1.InPlaceOnlyStrategy
+}
+
 // GetExpectedPCLQNamesGroupByOwner returns the expected unqualified PodClique names which are either owned by PodCliqueSet or PodCliqueScalingGroup.
 func GetExpectedPCLQNamesGroupByOwner(pcs *grovecorev1alpha1.PodCliqueSet) (expectedPCLQNamesForPCS []string, expectedPCLQNamesForPCSG []string) {
 	pcsgConfigs := pcs.Spec.Template.PodCliqueScalingGroupConfigs

operator/internal/controller/common/component/utils/podcliqueset_test.go

@@ -301,6 +301,24 @@ func TestIsAutoUpdateStrategy(t *testing.T) {
 			},
 			expected: false,
 		},
+		{
+			name: "in_place_if_possible_is_auto",
+			pcs: &grovecorev1alpha1.PodCliqueSet{
+				Spec: grovecorev1alpha1.PodCliqueSetSpec{
+					UpdateStrategy: &grovecorev1alpha1.PodCliqueSetUpdateStrategy{Type: grovecorev1alpha1.InPlaceIfPossibleStrategy},
+				},
+			},
+			expected: true,
+		},
+		{
+			name: "in_place_only_is_auto",
+			pcs: &grovecorev1alpha1.PodCliqueSet{
+				Spec: grovecorev1alpha1.PodCliqueSetSpec{
+					UpdateStrategy: &grovecorev1alpha1.PodCliqueSetUpdateStrategy{Type: grovecorev1alpha1.InPlaceOnlyStrategy},
+				},
+			},
+			expected: true,
+		},
 	}
 
 	for _, tc := range tests {
@@ -310,6 +328,51 @@ func TestIsAutoUpdateStrategy(t *testing.T) {
 	}
 }
 
+func TestIsInPlaceUpdateStrategy(t *testing.T) {
+	tests := []struct {
+		name     string
+		pcs      *grovecorev1alpha1.PodCliqueSet
+		expected bool
+	}{
+		{name: "nil_pcs", pcs: nil, expected: false},
+		{name: "nil_strategy", pcs: &grovecorev1alpha1.PodCliqueSet{}, expected: false},
+		{
+			name: "rolling_recreate",
+			pcs: &grovecorev1alpha1.PodCliqueSet{Spec: grovecorev1alpha1.PodCliqueSetSpec{
+				UpdateStrategy: &grovecorev1alpha1.PodCliqueSetUpdateStrategy{Type: grovecorev1alpha1.RollingRecreateStrategy},
+			}},
+			expected: false,
+		},
+		{
+			name: "on_delete",
+			pcs: &grovecorev1alpha1.PodCliqueSet{Spec: grovecorev1alpha1.PodCliqueSetSpec{
+				UpdateStrategy: &grovecorev1alpha1.PodCliqueSetUpdateStrategy{Type: grovecorev1alpha1.OnDeleteStrategy},
+			}},
+			expected: false,
+		},
+		{
+			name: "in_place_if_possible",
+			pcs: &grovecorev1alpha1.PodCliqueSet{Spec: grovecorev1alpha1.PodCliqueSetSpec{
+				UpdateStrategy: &grovecorev1alpha1.PodCliqueSetUpdateStrategy{Type: grovecorev1alpha1.InPlaceIfPossibleStrategy},
+			}},
+			expected: true,
+		},
+		{
+			name: "in_place_only",
+			pcs: &grovecorev1alpha1.PodCliqueSet{Spec: grovecorev1alpha1.PodCliqueSetSpec{
+				UpdateStrategy: &grovecorev1alpha1.PodCliqueSetUpdateStrategy{Type: grovecorev1alpha1.InPlaceOnlyStrategy},
+			}},
+			expected: true,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			assert.Equal(t, tc.expected, IsInPlaceUpdateStrategy(tc.pcs))
+		})
+	}
+}
+
 // TestGetPodCliqueSet tests the GetPodCliqueSet function
 func TestGetPodCliqueSet(t *testing.T) {
 	tests := []struct {