feat: add snapshot CPU compatibility contract

apis/v1/cocoonset_types.go

@@ -8,6 +8,7 @@ import (
 
 // CocoonSetSpec defines the desired state of a CocoonSet.
 // +kubebuilder:validation:XValidation:rule="!has(self.hibernatePolicy) || self.hibernatePolicy != 'release' || ((!has(self.agent.replicas) || self.agent.replicas == 0) && (!has(self.toolboxes) || size(self.toolboxes) == 0))",message="hibernatePolicy=release requires agent.replicas=0 and no toolboxes"
+// +kubebuilder:validation:XValidation:rule="!has(oldSelf.snapshotCompatibilityClass) || (has(self.snapshotCompatibilityClass) && self.snapshotCompatibilityClass == oldSelf.snapshotCompatibilityClass)",message="snapshotCompatibilityClass is immutable once set"
 type CocoonSetSpec struct {
 	// +optional
 	Suspend bool `json:"suspend,omitempty"`
@@ -27,6 +28,11 @@ type CocoonSetSpec struct {
 	// +kubebuilder:default=default
 	NodePool string `json:"nodePool,omitempty"`
 
+	// +optional
+	// +kubebuilder:validation:MaxLength=63
+	// +kubebuilder:validation:Pattern=`^(([A-Za-z0-9][-A-Za-z0-9_.]*)?[A-Za-z0-9])?$`
+	SnapshotCompatibilityClass string `json:"snapshotCompatibilityClass,omitempty"`
+
 	// NodeName pins the VM to a node (cross-node migrate). Empty = let the
 	// scheduler place it within NodePool and leave it alone; a value adds a
 	// hostname nodeAffinity so the pod lands there or stays Pending if it won't fit.

apis/v1/cocoonset_types_test.go

@@ -0,0 +1,26 @@
+package v1
+
+import (
+	"encoding/json"
+	"strings"
+	"testing"
+)
+
+func TestCocoonSetSpecSnapshotCompatibilityClassJSON(t *testing.T) {
+	spec := CocoonSetSpec{SnapshotCompatibilityClass: "n2-cascade-lake-v1"}
+	raw, err := json.Marshal(spec)
+	if err != nil {
+		t.Fatalf("marshal CocoonSetSpec: %v", err)
+	}
+	if !strings.Contains(string(raw), `"snapshotCompatibilityClass":"n2-cascade-lake-v1"`) {
+		t.Fatalf("snapshot compatibility class missing from JSON: %s", raw)
+	}
+
+	raw, err = json.Marshal(CocoonSetSpec{})
+	if err != nil {
+		t.Fatalf("marshal empty CocoonSetSpec: %v", err)
+	}
+	if strings.Contains(string(raw), "snapshotCompatibilityClass") {
+		t.Fatalf("empty snapshot compatibility class must be omitted: %s", raw)
+	}
+}

apis/v1/crds/cocoonset.cocoonstack.io_cocoonsets.yaml

@@ -267,6 +267,14 @@ spec:
               nodePool:
                 default: default
                 type: string
+              snapshotCompatibilityClass:
+                description: |-
+                  SnapshotCompatibilityClass selects nodes that expose a guest-visible CPU
+                  ABI compatible with this set's memory snapshots. It is independent from
+                  NodePool so multiple workload pools can share one snapshot class.
+                maxLength: 63
+                pattern: ^(([A-Za-z0-9][-A-Za-z0-9_.]*)?[A-Za-z0-9])?$
+                type: string
               snapshotPolicy:
                 default: always
                 description: SnapshotPolicy defines when VM snapshots are taken.
@@ -436,6 +444,9 @@ spec:
               rule: '!has(self.hibernatePolicy) || self.hibernatePolicy != ''release''
                 || ((!has(self.agent.replicas) || self.agent.replicas == 0) && (!has(self.toolboxes)
                 || size(self.toolboxes) == 0))'
+            - message: snapshotCompatibilityClass is immutable once set
+              rule: '!has(oldSelf.snapshotCompatibilityClass) || (has(self.snapshotCompatibilityClass)
+                && self.snapshotCompatibilityClass == oldSelf.snapshotCompatibilityClass)'
           status:
             description: CocoonSetStatus represents the observed state of a CocoonSet.
             properties:

meta/keys.go

@@ -18,6 +18,8 @@ const (
 	LabelNodePool = "cocoonstack.io/pool"
 	// DefaultNodePool is the pool name used when LabelNodePool is unset.
 	DefaultNodePool = "default"
+	// LabelSnapshotCompatibilityClass selects nodes whose guest-visible CPU ABI
+	LabelSnapshotCompatibilityClass = "cocoonstack.io/snapshot-cpu-class"
 
 	// AnnotationMode declares the VM provisioning mode (clone / run / static).
 	AnnotationMode = "cocoonset.cocoonstack.io/mode"