Description

Add the SessionStorageConfig shared struct and scaling fields to both CRDs, then regenerate deepcopy and CRD manifests. Specifically:

1. MCPServer types (mcpserver_types.go): Add SessionStorageConfig struct, Replicas *int32, BackendReplicas *int32, and SessionStorage *SessionStorageConfig to MCPServerSpec.
2. VirtualMCPServer types (virtualmcpserver_types.go): Add Replicas *int32 and SessionStorage *SessionStorageConfig to VirtualMCPServerSpec, reusing the SessionStorageConfig struct defined above.
3. Regeneration: Run task operator-generate and task operator-manifests to regenerate zz_generated.deepcopy.go and the CRD YAML files.

These changes are the foundation for horizontal scaling support in the ToolHive operator (THV-0047). All downstream reconciler and deployment-builder tasks depend on this compilable, up-to-date API surface.

Note: Originally split into three tasks (TASK-001 #267, TASK-002 #269, TASK-003 #275). Merged because all three are always shipped in a single PR — the type changes and regeneration are inseparable from a compilation standpoint.

Parent epic: stacklok/stacklok-epics#264

Dependencies: None (root task)
Blocks: TASK-002 (MCPServer Reconciler), TASK-003 (MCPServer RunConfig Injection), TASK-004 (VirtualMCPServer Deployment Builder), TASK-005 (VirtualMCPServer ConfigMap Injection), TASK-006 (Unit Tests)

Acceptance Criteria

MCPServer types (mcpserver_types.go)

• SessionStorageConfig struct is defined with fields: Provider (required, enum memory|redis), Address (optional), DB (optional int32, default 0), KeyPrefix (optional), and PasswordRef (optional *SecretKeyRef)
• CEL validation rule on SessionStorageConfig enforces that address is required when provider == "redis"
• MCPServerSpec includes Replicas *int32, BackendReplicas *int32, and SessionStorage *SessionStorageConfig with // +optional and omitempty tags
• PasswordRef reuses the existing SecretKeyRef type — not redeclared

VirtualMCPServer types (virtualmcpserver_types.go)

• VirtualMCPServerSpec includes Replicas *int32 and SessionStorage *SessionStorageConfig with // +optional and omitempty tags
• SessionStorageConfig is referenced from mcpserver_types.go — not redeclared in this file

Regeneration

• task operator-generate runs without error and regenerates zz_generated.deepcopy.go with DeepCopyInto for SessionStorageConfig and updated deepcopy for both specs
• task operator-manifests regenerates CRD YAMLs in deploy/charts/operator-crds/files/crds/ including the CEL validation rule and enum constraints
• go build ./cmd/thv-operator/... passes after regeneration
• go test ./cmd/thv-operator/... passes after regeneration
• All generated files committed in the same PR
• Code reviewed and approved

Technical Approach

Step 1 — MCPServer types

Add SessionStorageConfig struct and three new fields to MCPServerSpec in mcpserver_types.go. Follow the +optional pattern for pointer fields (OIDCConfig, AuthzConfig). Use +kubebuilder:validation:Enum=memory;redis on Provider and a struct-level +kubebuilder:validation:XValidation rule for the address-required-for-redis constraint.

// +kubebuilder:validation:XValidation:rule="self.provider == 'redis' ? has(self.address) : true",message="address is required when provider is redis"
type SessionStorageConfig struct {
    // +kubebuilder:validation:Enum=memory;redis
    // +kubebuilder:validation:Required
    Provider string `json:"provider"`
    // +optional
    Address string `json:"address,omitempty"`
    // +kubebuilder:default=0
    // +optional
    DB int32 `json:"db,omitempty"`
    // +optional
    KeyPrefix string `json:"keyPrefix,omitempty"`
    // +optional
    PasswordRef *SecretKeyRef `json:"passwordRef,omitempty"`
}

New MCPServerSpec fields:

// +optional
Replicas *int32 `json:"replicas,omitempty"`
// +optional
BackendReplicas *int32 `json:"backendReplicas,omitempty"`
// +optional
SessionStorage *SessionStorageConfig `json:"sessionStorage,omitempty"`

Step 2 — VirtualMCPServer types

Add two new fields to VirtualMCPServerSpec in virtualmcpserver_types.go after EmbeddingServerRef:

// +optional
Replicas *int32 `json:"replicas,omitempty"`
// +optional
SessionStorage *SessionStorageConfig `json:"sessionStorage,omitempty"`

Step 3 — Regeneration

task operator-generate   # regenerates zz_generated.deepcopy.go
task operator-manifests  # regenerates CRD YAMLs + Helm wrappers
go build ./cmd/thv-operator/...
go test -ldflags=-extldflags=-Wl,-w ./cmd/thv-operator/... 2>&1 | grep -v '/test-integration'

Do not run task crdref-gen (documentation generation, out of scope).

Code Pointers

• cmd/thv-operator/api/v1alpha1/mcpserver_types.go — Add SessionStorageConfig struct and three new MCPServerSpec fields
• cmd/thv-operator/api/v1alpha1/virtualmcpserver_types.go — Add two new fields to VirtualMCPServerSpec
• cmd/thv-operator/api/v1alpha1/mcpexternalauthconfig_types.go — Source of SecretKeyRef (lines 561–569) and CEL validation patterns (lines 44–49)
• cmd/thv-operator/api/v1alpha1/zz_generated.deepcopy.go — Regenerated; do not edit by hand

Out of Scope

• Reconciler logic changes — TASK-002 through TASK-005
• Unit tests for reconciler behavior — TASK-006
• runner.RunConfig changes — TASK-003

References

• Epic THV-0047: stacklok/stacklok-epics#264
• RFC THV-0047: RFC: Horizontal Scaling for vMCP and Proxy Runner toolhive-rfcs#47
• Merged from: Add go:// transport protocol for golang containers #269 (VirtualMCPServer CRD Type Changes), Fix StatefulSet container configuration in Kubernetes runtime #275 (Regenerate Deepcopy and CRD Manifests)