Allow sandbox claim to specify whether to get pod from sandbox warm pool

extensions/api/v1alpha1/sandboxclaim_types.go

@@ -26,6 +26,30 @@ const (
 	ClaimExpiredReason = "ClaimExpired"
 )
 
+// WarmPoolPolicy describes the policy for using warm pools.
+// It can be one of the following:
+//   - "none": Do not use any warm pool, always create fresh sandboxes
+//   - "default": Select from all available warm pools that match the template (default)
+//   - A warm pool name: Select only from the specified warm pool (e.g., "fast-pool", "secure-pool")
+type WarmPoolPolicy string
+
+const (
+	// WarmPoolPolicyNone indicates that no warm pool should be used.
+	// A fresh sandbox will always be created.
+	WarmPoolPolicyNone WarmPoolPolicy = "none"
+
+	// WarmPoolPolicyDefault indicates the default behavior: select from all
+	// available warm pools that match the template. This is the default behavior
+	// if warmpool is not specified.
+	WarmPoolPolicyDefault WarmPoolPolicy = "default"
+)
+
+// IsSpecificPool returns true if the policy specifies a specific warm pool name
+// (not "none" or "default").
+func (p WarmPoolPolicy) IsSpecificPool() bool {
+	return p != WarmPoolPolicyNone && p != WarmPoolPolicyDefault && p != ""
+}
+
 // ShutdownPolicy describes the policy for shutting down the underlying Sandbox when the SandboxClaim expires.
 // +kubebuilder:validation:Enum=Delete;DeleteForeground;Retain
 type ShutdownPolicy string
@@ -80,6 +104,14 @@ type SandboxClaimSpec struct {
 	// lifecycle defines when and how the SandboxClaim should be shut down.
 	// +optional
 	Lifecycle *Lifecycle `json:"lifecycle,omitempty"`
+
+	// warmpool specifies the warm pool policy for sandbox adoption.
+	// - "none": Do not use any warm pool, always create fresh sandboxes
+	// - "default": Use default behavior, select from all matching warm pools (default)
+	// - A warm pool name: Select only from the specified warm pool (e.g., "fast-pool", "secure-pool")
+	// +optional
+	// +kubebuilder:default=default
+	WarmPool *WarmPoolPolicy `json:"warmpool,omitempty"`
 }
 
 // SandboxClaimStatus defines the observed state of Sandbox.

extensions/controllers/sandboxclaim_controller.go

@@ -44,6 +44,14 @@ import (
 // ErrTemplateNotFound is a sentinel error indicating a SandboxTemplate was not found.
 var ErrTemplateNotFound = errors.New("SandboxTemplate not found")
 
+// getWarmPoolPolicy returns the effective warm pool policy for a claim.
+func getWarmPoolPolicy(claim *extensionsv1alpha1.SandboxClaim) extensionsv1alpha1.WarmPoolPolicy {
+	if claim.Spec.WarmPool != nil {
+		return *claim.Spec.WarmPool
+	}
+	return extensionsv1alpha1.WarmPoolPolicyDefault
+}
+
 // SandboxClaimReconciler reconciles a SandboxClaim object
 type SandboxClaimReconciler struct {
 	client.Client
@@ -604,6 +612,7 @@ func (r *SandboxClaimReconciler) getOrCreateSandbox(ctx context.Context, claim *
 		return nil, fmt.Errorf("failed to list sandboxes: %w", err)
 	}
 
+	policy := getWarmPoolPolicy(claim)
 	templateHash := sandboxcontrollers.NameHash(claim.Spec.TemplateRef.Name)
 	var adoptionCandidates []*v1alpha1.Sandbox
 
@@ -619,6 +628,11 @@ func (r *SandboxClaimReconciler) getOrCreateSandbox(ctx context.Context, claim *
 			return sb, nil
 		}
 
+		// Skip warm pool adoption entirely if policy is "none"
+		if policy == extensionsv1alpha1.WarmPoolPolicyNone {
+			continue
+		}
+
 		// Collect adoption candidates from warm pool
 		if _, ok := sb.Labels[warmPoolSandboxLabel]; !ok {
 			continue
@@ -630,18 +644,35 @@ func (r *SandboxClaimReconciler) getOrCreateSandbox(ctx context.Context, claim *
 		if controllerRef != nil && controllerRef.Kind != "SandboxWarmPool" {
 			continue
 		}
+
+		// If a specific pool is requested, only consider sandboxes from that pool
+		if policy.IsSpecificPool() {
+			specificPoolHash := sandboxcontrollers.NameHash(string(policy))
+			if sb.Labels[warmPoolSandboxLabel] != specificPoolHash {
+				continue
+			}
+		}
+
 		adoptionCandidates = append(adoptionCandidates, sb)
 	}
 
+	if policy == extensionsv1alpha1.WarmPoolPolicyNone {
+		logger.Info("Skipping warm pool adoption based on warmpool policy", "claim", claim.Name, "warmpool", policy)
+		return nil, nil
+	}
+
 	// Try to adopt from warm pool
 	if len(adoptionCandidates) > 0 {
+		logger.V(1).Info("Found warm pool adoption candidates", "count", len(adoptionCandidates), "claim", claim.Name, "warmpool", policy)
 		adopted, err := r.adoptSandboxFromCandidates(ctx, claim, adoptionCandidates)
 		if err != nil {
 			return nil, err
 		}
 		if adopted != nil {
 			return adopted, nil
 		}
+	} else if policy.IsSpecificPool() {
+		logger.Info("No available sandboxes in specified warm pool", "warmPool", string(policy), "claim", claim.Name)
 	}
 
 	// No warm pool sandbox available; caller decides whether to create