openshift · jeff-roche · Sep 9, 2026 · Sep 15, 2026 · Sep 15, 2026 · Sep 16, 2026
diff --git a/.golangci.yaml b/.golangci.yaml
@@ -121,6 +121,21 @@ linters:
         # to enforce specific condition types are always present.
         path: etcd/v1/types_pacemakercluster.go
         text: "conditions: Conditions field in (PacemakerClusterStatus|PacemakerClusterNodeStatus|PacemakerClusterFencingAgentStatus|PacemakerClusterResourceStatus) is missing the following markers: optional"
+      - linters:
+        - kubeapilinter
+        # Empty lists are meaningful: no available transitions, or no completed evaluation condition yet.
+        path: config/v1/types_infrastructure_transitions.go
+        text: 'minlength: field TopologyTransitionStatus\.(AvailableTransitions|Conditions) must have a minimum items'
+      - linters:
+        - kubeapilinter
+        # Keep the pointer so nil means no topology transition has started; omitempty omits nil.
+        path: config/v1/types_infrastructure_transitions.go
+        text: 'optionalfields: field TopologyTransitionStatus\.CurrentTransition'
+      - linters:
+        - kubeapilinter
+        # Keep an evaluated empty list serialized as [] rather than omitting this required field.
+        path: config/v1/types_infrastructure_transitions.go
+        text: 'requiredfields: field TopologyTransitionStatus\.AvailableTransitions should have the omitempty tag'
       - linters:
         - kubeapilinter
         path: features|payload-command/

diff --git a/config/v1/tests/infrastructures.config.openshift.io/AAA_ungated.yaml b/config/v1/tests/infrastructures.config.openshift.io/AAA_ungated.yaml
@@ -635,6 +635,29 @@ tests:
                 type: UserManaged
             type: BareMetal
       expectedStatusError: 'status.platformStatus.baremetal.loadBalancer.type: Invalid value: "string": type is immutable once set'
+    - name: Should prune topologyTransitionStatus when MutableTopology is disabled
+      initial: |
+        apiVersion: config.openshift.io/v1
+        kind: Infrastructure
+        spec: {}
+        status:
+          controlPlaneTopology: SingleReplica
+      updated: |
+        apiVersion: config.openshift.io/v1
+        kind: Infrastructure
+        spec: {}
+        status:
+          controlPlaneTopology: SingleReplica
+          topologyTransitionStatus:
+            availableTransitions: []
+      expected: |
+        apiVersion: config.openshift.io/v1
+        kind: Infrastructure
+        spec: {}
+        status:
+          controlPlaneTopology: SingleReplica
+          infrastructureTopology: HighlyAvailable
+          cpuPartitioning: None
     - name: Should not allow changing the immutable OpenStack load balancer type field
       initial: |
         apiVersion: config.openshift.io/v1

diff --git a/config/v1/tests/infrastructures.config.openshift.io/MutableTopology.yaml b/config/v1/tests/infrastructures.config.openshift.io/MutableTopology.yaml
@@ -259,3 +259,227 @@ tests:
         spec:
           controlPlaneTopology: InvalidValue
       expectedError: 'spec.controlPlaneTopology: Unsupported value: "InvalidValue": supported values: "HighlyAvailable", "SingleReplica"'
+    - name: Should allow updating Infrastructure status without topologyTransitionStatus
+      initial: |
+        apiVersion: config.openshift.io/v1
+        kind: Infrastructure
+        spec: {}
+        status:
+          controlPlaneTopology: SingleReplica
+      updated: |
+        apiVersion: config.openshift.io/v1
+        kind: Infrastructure
+        spec: {}
+        status:
+          controlPlaneTopology: SingleReplica
+          infrastructureTopology: HighlyAvailable
+      expected: |
+        apiVersion: config.openshift.io/v1
+        kind: Infrastructure
+        spec: {}
+        status:
+          controlPlaneTopology: SingleReplica
+          infrastructureTopology: HighlyAvailable
+          cpuPartitioning: None
+    - name: Should allow an empty availableTransitions list after successful evaluation
+      initial: |
+        apiVersion: config.openshift.io/v1
+        kind: Infrastructure
+        spec: {}
+        status:
+          controlPlaneTopology: SingleReplica
+      updated: |
+        apiVersion: config.openshift.io/v1
+        kind: Infrastructure
+        spec: {}
+        status:
+          controlPlaneTopology: SingleReplica
+          topologyTransitionStatus:
+            availableTransitions: []
+            conditions:
+            - type: TopologyTransitionsEvaluated
+              status: "True"
+              lastTransitionTime: "2025-01-01T00:00:00Z"
+              reason: EvaluationComplete
+              message: No transitions are available
+      expected: |
+        apiVersion: config.openshift.io/v1
+        kind: Infrastructure
+        spec: {}
+        status:
+          controlPlaneTopology: SingleReplica
+          infrastructureTopology: HighlyAvailable
+          cpuPartitioning: None
+          topologyTransitionStatus:
+            availableTransitions: []
+            conditions:
+            - type: TopologyTransitionsEvaluated
+              status: "True"
+              lastTransitionTime: "2025-01-01T00:00:00Z"
+              reason: EvaluationComplete
+              message: No transitions are available
+    - name: Should allow reporting current transition progress
+      initial: |
+        apiVersion: config.openshift.io/v1
+        kind: Infrastructure
+        spec: {}
+        status:
+          controlPlaneTopology: SingleReplica
+          infrastructureTopology: SingleReplica
+      updated: |
+        apiVersion: config.openshift.io/v1
+        kind: Infrastructure
+        spec: {}
+        status:
+          controlPlaneTopology: SingleReplica
+          infrastructureTopology: SingleReplica
+          topologyTransitionStatus:
+            availableTransitions:
+            - source:
+                controlPlaneTopology: SingleReplica
+                infrastructureTopology: SingleReplica
+              target:
+                controlPlaneTopology: HighlyAvailable
+                infrastructureTopology: HighlyAvailable
+              reason: PreflightCheckFailed
+            currentTransition:
+              status: Partial
+              reason: TransitionInProgress
+              message: Applying topology changes
+              startedTime: "2025-01-01T00:00:00Z"
+      expected: |
+        apiVersion: config.openshift.io/v1
+        kind: Infrastructure
+        spec: {}
+        status:
+          controlPlaneTopology: SingleReplica
+          infrastructureTopology: SingleReplica
+          cpuPartitioning: None
+          topologyTransitionStatus:
+            availableTransitions:
+            - source:
+                controlPlaneTopology: SingleReplica
+                infrastructureTopology: SingleReplica
+              target:
+                controlPlaneTopology: HighlyAvailable
+                infrastructureTopology: HighlyAvailable
+              reason: PreflightCheckFailed
+            currentTransition:
+              status: Partial
+              reason: TransitionInProgress
+              message: Applying topology changes
+              startedTime: "2025-01-01T00:00:00Z"
+    - name: Should reject a topology transition reason that is not CamelCase
+      initial: |
+        apiVersion: config.openshift.io/v1
+        kind: Infrastructure
+        spec: {}
+        status:
+          controlPlaneTopology: SingleReplica
+          infrastructureTopology: SingleReplica
+      updated: |
+        apiVersion: config.openshift.io/v1
+        kind: Infrastructure
+        spec: {}
+        status:
+          controlPlaneTopology: SingleReplica
+          infrastructureTopology: SingleReplica
+          topologyTransitionStatus:
+            availableTransitions:
+            - source:
+                controlPlaneTopology: SingleReplica
+                infrastructureTopology: SingleReplica
+              target:
+                controlPlaneTopology: HighlyAvailable
+                infrastructureTopology: HighlyAvailable
+              reason: preflightCheckFailed
+      expectedStatusError: "reason must be CamelCase, matching ^[A-Z][A-Za-z0-9]*$"
+    - name: Should reject an available transition whose source does not match status topology
+      initial: |
+        apiVersion: config.openshift.io/v1
+        kind: Infrastructure
+        spec: {}
+        status:
+          controlPlaneTopology: SingleReplica
+          infrastructureTopology: SingleReplica
+      updated: |
+        apiVersion: config.openshift.io/v1
+        kind: Infrastructure
+        spec: {}
+        status:
+          controlPlaneTopology: SingleReplica
+          infrastructureTopology: SingleReplica
+          topologyTransitionStatus:
+            availableTransitions:
+            - source:
+                controlPlaneTopology: HighlyAvailable
+                infrastructureTopology: HighlyAvailable
+              target:
+                controlPlaneTopology: SingleReplica
+                infrastructureTopology: SingleReplica
+      expectedStatusError: "transition sources must match the current status topology"
+    - name: Should enforce the supported maximum available transition count
+      initial: |
+        apiVersion: config.openshift.io/v1
+        kind: Infrastructure
+        spec: {}
+        status:
+          controlPlaneTopology: SingleReplica
+          infrastructureTopology: SingleReplica
+      updated: |
+        apiVersion: config.openshift.io/v1
+        kind: Infrastructure
+        spec: {}
+        status:
+          controlPlaneTopology: SingleReplica
+          infrastructureTopology: SingleReplica
+          topologyTransitionStatus:
+            availableTransitions:
+            - source:
+                controlPlaneTopology: SingleReplica
+                infrastructureTopology: SingleReplica
+              target:
+                controlPlaneTopology: HighlyAvailable
+                infrastructureTopology: HighlyAvailable
+            - source:
+                controlPlaneTopology: SingleReplica
+                infrastructureTopology: SingleReplica
+              target:
+                controlPlaneTopology: HighlyAvailable
+                infrastructureTopology: HighlyAvailable
+      expectedStatusError: "Too many: 2: must have at most 1 items"
+    - name: Should require availableTransitions when topologyTransitionStatus is set
+      initial: |
+        apiVersion: config.openshift.io/v1
+        kind: Infrastructure
+        spec: {}
+        status:
+          controlPlaneTopology: SingleReplica
+      updated: |
+        apiVersion: config.openshift.io/v1
+        kind: Infrastructure
+        spec: {}
+        status:
+          controlPlaneTopology: SingleReplica
+          topologyTransitionStatus:
+            conditions: []
+      expectedStatusError: "Required value"
+    - name: Should require status on currentTransition
+      initial: |
+        apiVersion: config.openshift.io/v1
+        kind: Infrastructure
+        spec: {}
+        status:
+          controlPlaneTopology: SingleReplica
+      updated: |
+        apiVersion: config.openshift.io/v1
+        kind: Infrastructure
+        spec: {}
+        status:
+          controlPlaneTopology: SingleReplica
+          topologyTransitionStatus:
+            availableTransitions: []
+            currentTransition:
+              reason: TransitionInProgress
+              message: Applying topology changes
+      expectedStatusError: "Required value"
diff --git a/config/v1/types_infrastructure.go b/config/v1/types_infrastructure.go
@@ -20,6 +20,7 @@ import (
 // +kubebuilder:subresource:status
 // +kubebuilder:metadata:annotations=release.openshift.io/bootstrap-required=true
 // +openshift:validation:FeatureGateAwareXValidation:featureGate=MutableTopology,rule="!has(self.spec.controlPlaneTopology) || (has(oldSelf.spec.controlPlaneTopology) && self.spec.controlPlaneTopology == oldSelf.spec.controlPlaneTopology) || (has(self.status.controlPlaneTopology) && self.spec.controlPlaneTopology == self.status.controlPlaneTopology) || (has(self.status.controlPlaneTopology) && self.status.controlPlaneTopology == 'SingleReplica' && self.spec.controlPlaneTopology == 'HighlyAvailable')",message="spec.controlPlaneTopology must match status.controlPlaneTopology or be set to HighlyAvailable when status.controlPlaneTopology is SingleReplica"
+// +openshift:validation:FeatureGateAwareXValidation:featureGate=MutableTopology,rule="!has(self.status) || !has(self.status.topologyTransitionStatus) || self.status.topologyTransitionStatus.availableTransitions.all(t, has(self.status.controlPlaneTopology) && has(self.status.infrastructureTopology) && t.source.controlPlaneTopology == self.status.controlPlaneTopology && t.source.infrastructureTopology == self.status.infrastructureTopology)",message="transition sources must match the current status topology"
 type Infrastructure struct {
 	metav1.TypeMeta `json:",inline"`
 
@@ -138,6 +139,12 @@ type InfrastructureStatus struct {
 	// +optional
 	InfrastructureTopology TopologyMode `json:"infrastructureTopology,omitempty"`
 
+	// topologyTransitionStatus reports available topology transitions and current progress, if any.
+	// It is omitted until the topology controller evaluates transitions.
+	// +openshift:enable:FeatureGate=MutableTopology
+	// +optional
+	TopologyTransitionStatus *TopologyTransitionStatus `json:"topologyTransitionStatus,omitempty"`
+
 	// cpuPartitioning expresses if CPU partitioning is a currently enabled feature in the cluster.
 	// CPU Partitioning means that this cluster can support partitioning workloads to specific CPU Sets.
 	// Valid values are "None" and "AllNodes". When omitted, the default value is "None".