feat(BA-6242): give custom runtime variant a default health check

changes/11863.feature.md

@@ -0,0 +1 @@
+Add an `enable` flag to model-deployment health checks (default off), making health checks opt-in. The custom runtime variant ships with a disabled default health check, and a model-definition file that declares a health check is treated as enabled.

docs/manager/graphql-reference/supergraph.graphql

@@ -9673,6 +9673,11 @@ input ModelDeploymentNetworkAccessInput
 type ModelHealthCheck
   @join__type(graph: STRAWBERRY)
 {
+  """
+  Whether the route is health-checked. When false the route activates immediately.
+  """
+  enable: Boolean!
+
   """Interval in seconds between health checks."""
   interval: Float!
 
@@ -9696,6 +9701,11 @@ type ModelHealthCheck
 input ModelHealthCheckInput
   @join__type(graph: STRAWBERRY)
 {
+  """
+  Whether the route should be health-checked. When false the route activates immediately and the remaining fields are ignored.
+  """
+  enable: Boolean! = false
+
   """Interval in seconds between health checks."""
   interval: Float = null
 

docs/manager/graphql-reference/v2-schema.graphql

@@ -6424,6 +6424,11 @@ input ModelDeploymentNetworkAccessInput {
 
 """Added in 26.4.2. Health check configuration for a model service."""
 type ModelHealthCheck {
+  """
+  Whether the route is health-checked. When false the route activates immediately.
+  """
+  enable: Boolean!
+
   """Interval in seconds between health checks."""
   interval: Float!
 
@@ -6445,6 +6450,11 @@ type ModelHealthCheck {
 
 """Added in 26.4.0. Health check configuration for a model service."""
 input ModelHealthCheckInput {
+  """
+  Whether the route should be health-checked. When false the route activates immediately and the remaining fields are ignored.
+  """
+  enable: Boolean! = false
+
   """Interval in seconds between health checks."""
   interval: Float = null
 

fixtures/manager/example-runtime-variants.json

@@ -12,6 +12,7 @@
               "start_command": ["vllm", "serve", "{model_path}"],
               "port": 8000,
               "health_check": {
+                "enable": false,
                 "path": "/health",
                 "interval": 10.0,
                 "max_retries": 10,
@@ -33,6 +34,7 @@
             "service": {
               "port": 8000,
               "health_check": {
+                "enable": false,
                 "path": "/v1/health/ready",
                 "interval": 10.0,
                 "max_retries": 10,
@@ -70,6 +72,7 @@
               "start_command": ["text-generation-launcher", "--model-id", "{model_path}"],
               "port": 3000,
               "health_check": {
+                "enable": false,
                 "path": "/info",
                 "interval": 10.0,
                 "max_retries": 10,
@@ -98,6 +101,7 @@
               ],
               "port": 9001,
               "health_check": {
+                "enable": false,
                 "path": "/health",
                 "interval": 10.0,
                 "max_retries": 10,
@@ -120,6 +124,7 @@
               "start_command": ["max", "serve", "--model", "{model_path}"],
               "port": 8000,
               "health_check": {
+                "enable": false,
                 "path": "/health",
                 "interval": 10.0,
                 "max_retries": 10,
@@ -135,7 +140,20 @@
       "description": "Custom (Default)",
       "reads_vfolder_config_files": true,
       "default_model_definition": {
-        "models": null
+        "models": [
+          {
+            "name": "custom-model",
+            "service": {
+              "health_check": {
+                "enable": false,
+                "path": "/health",
+                "interval": 10.0,
+                "max_retries": 10,
+                "initial_delay": 1800.0
+              }
+            }
+          }
+        ]
       }
     }
   ]

src/ai/backend/common/config.py

@@ -170,12 +170,21 @@ class PreStartAction(BaseConfigModel):
 
 
 class ModelHealthCheck(BaseConfigModel):
+    enable: bool = Field(
+        default=False,
+        description=(
+            "Whether the route should be health-checked. When false the route "
+            "becomes active immediately and the remaining fields are ignored."
+        ),
+        examples=[False],
+    )
     interval: float = Field(
         default=10.0,
         description="Interval in seconds between health checks.",
         examples=[10.0],
     )
     path: str = Field(
+        default="/health",
         description="Path to check for health status.",
         examples=["/health"],
     )
@@ -351,6 +360,7 @@ def _merge_service_config(
         hb, ho = base.health_check, override.health_check
         hs = ho.model_fields_set
         health_check = ModelHealthCheck.model_construct(
+            enable=_pick(hb.enable, ho.enable, "enable" in hs),
             interval=_pick(hb.interval, ho.interval, "interval" in hs),
             path=_pick(hb.path, ho.path, "path" in hs),
             max_retries=_pick(hb.max_retries, ho.max_retries, "max_retries" in hs),
@@ -441,9 +451,8 @@ def merge(self, override: ModelDefinition) -> ModelDefinition:
 
     def health_check_config(self) -> ModelHealthCheck | None:
         for model in self.models:
-            if model.service and model.service.health_check:
-                if model.service.health_check is not None:
-                    return model.service.health_check
+            if model.service and model.service.health_check and model.service.health_check.enable:
+                return model.service.health_check
         return None
 
     def with_args_appended(self, args: list[str]) -> ModelDefinition:
@@ -481,6 +490,7 @@ def with_args_appended(self, args: list[str]) -> ModelDefinition:
 
 
 class ModelHealthCheckDraft(BaseConfigModel):
+    enable: bool | None = None
     interval: float | None = None
     path: str | None = None
     max_retries: int | None = None
@@ -491,8 +501,6 @@ class ModelHealthCheckDraft(BaseConfigModel):
     def to_resolved(self) -> ModelHealthCheck:
         # Drop unset (None) fields so the strict type's ``Field(default=...)``
         # declarations remain the single source of truth for default values.
-        # Missing required fields (e.g. ``path``) surface as the strict
-        # type's ``BackendAISchemaValidationFailed`` via ``model_validate``.
         return ModelHealthCheck.model_validate(self.model_dump(exclude_none=True))
 
 
@@ -511,10 +519,9 @@ def _wrap_str_start_command(cls, data: Any) -> Any:
     def to_resolved(self) -> ModelServiceConfig:
         # Drop unset (None) scalars so the strict type's ``Field(default=...)``
         # declarations remain the single source of truth for default values;
-        # resolve the nested ``health_check`` draft explicitly so its own
-        # required-field check (``path``) fires through its own
-        # ``model_validate``. Missing required fields (e.g. ``port``)
-        # surface as ``BackendAISchemaValidationFailed``.
+        # resolve the nested ``health_check`` draft explicitly. Missing
+        # required fields (e.g. ``port``) surface as
+        # ``BackendAISchemaValidationFailed``.
         payload = self.model_dump(exclude_none=True, exclude={"health_check"})
         payload["health_check"] = self.health_check.to_resolved() if self.health_check else None
         return ModelServiceConfig.model_validate(payload)
@@ -547,6 +554,7 @@ def _merge_health_check_draft(
 ) -> ModelHealthCheckDraft:
     s = override.model_fields_set
     return ModelHealthCheckDraft.model_construct(
+        enable=_pick(base.enable, override.enable, "enable" in s),
         interval=_pick(base.interval, override.interval, "interval" in s),
         path=_pick(base.path, override.path, "path" in s),
         max_retries=_pick(base.max_retries, override.max_retries, "max_retries" in s),
@@ -650,6 +658,28 @@ def to_resolved(self) -> ModelDefinition:
             "models": [m.to_resolved() for m in (self.models or [])],
         })
 
+    @classmethod
+    def from_file_payload(cls, payload: Mapping[str, Any]) -> ModelDefinitionDraft:
+        """Parse a model-definition file into a draft, normalizing the ``health_check`` block."""
+        # Dump by field name so the keys below match regardless of snake/kebab input.
+        data = cls.model_validate(dict(payload)).model_dump(exclude_unset=True, by_alias=False)
+        for model in data.get("models") or []:
+            service = model.get("service")
+            if service is None:
+                continue
+            if "health_check" not in service:
+                continue
+            health_check = service["health_check"]
+            # An empty health_check (null or {}) is an explicit opt-out; disable it so it
+            # overrides any enabled baseline instead of inheriting one.
+            if not health_check:
+                service["health_check"] = {"enable": False}
+                continue
+            # A non-empty block opts in; default enable to True when unset.
+            if health_check.get("enable") is None:
+                health_check["enable"] = True
+        return cls.model_validate(data)
+
 
 def find_config_file(daemon_name: str) -> Path:
     toml_path_from_env = os.environ.get("BACKEND_CONFIG_FILE", None)

src/ai/backend/common/dto/manager/v2/deployment/request.py

@@ -122,6 +122,7 @@
 
 
 class ModelHealthCheckInput(BaseRequestModel):
+    enable: bool = False
     interval: float | None = None
     path: str | None = None
     max_retries: int | None = None

src/ai/backend/common/dto/manager/v2/deployment/types.py

@@ -278,6 +278,10 @@ class PreStartActionInfoDTO(BaseResponseModel):
 class ModelHealthCheckInfoDTO(BaseResponseModel):
     """Output DTO for model health check configuration."""
 
+    enable: bool = Field(
+        default=False,
+        description="Whether the route is health-checked. When false the route activates immediately.",
+    )
     interval: float = Field(description="Interval in seconds between health checks.")
     path: str = Field(description="Path to check for health status.")
     max_retries: int = Field(description="Maximum number of retries for health check.")

src/ai/backend/install/fixtures/example-runtime-variants.json

@@ -12,6 +12,7 @@
               "start_command": ["vllm", "serve", "{model_path}"],
               "port": 8000,
               "health_check": {
+                "enable": false,
                 "path": "/health",
                 "interval": 10.0,
                 "max_retries": 10,
@@ -33,6 +34,7 @@
             "service": {
               "port": 8000,
               "health_check": {
+                "enable": false,
                 "path": "/v1/health/ready",
                 "interval": 10.0,
                 "max_retries": 10,
@@ -70,6 +72,7 @@
               "start_command": ["text-generation-launcher", "--model-id", "{model_path}"],
               "port": 3000,
               "health_check": {
+                "enable": false,
                 "path": "/info",
                 "interval": 10.0,
                 "max_retries": 10,
@@ -98,6 +101,7 @@
               ],
               "port": 9001,
               "health_check": {
+                "enable": false,
                 "path": "/health",
                 "interval": 10.0,
                 "max_retries": 10,
@@ -120,6 +124,7 @@
               "start_command": ["max", "serve", "--model", "{model_path}"],
               "port": 8000,
               "health_check": {
+                "enable": false,
                 "path": "/health",
                 "interval": 10.0,
                 "max_retries": 10,
@@ -135,7 +140,20 @@
       "description": "Custom (Default)",
       "reads_vfolder_config_files": true,
       "default_model_definition": {
-        "models": null
+        "models": [
+          {
+            "name": "custom-model",
+            "service": {
+              "health_check": {
+                "enable": false,
+                "path": "/health",
+                "interval": 10.0,
+                "max_retries": 10,
+                "initial_delay": 1800.0
+              }
+            }
+          }
+        ]
       }
     }
   ]

src/ai/backend/manager/api/adapters/deployment_revision_preset/adapter.py

@@ -135,6 +135,7 @@ def _pre_start_action_to_dto(action: PreStartAction) -> PreStartActionInfoDTO:
 
 def _model_health_check_to_dto(check: ModelHealthCheck) -> ModelHealthCheckInfoDTO:
     return ModelHealthCheckInfoDTO(
+        enable=check.enable,
         interval=check.interval,
         path=check.path,
         max_retries=check.max_retries,

src/ai/backend/manager/api/gql/deployment/types/revision.py

@@ -357,6 +357,16 @@ class PreStartActionGQL:
     name="ModelHealthCheck",
 )
 class ModelHealthCheckGQL:
+    enable: bool = gql_added_field(
+        BackendAIGQLMeta(
+            added_version=NEXT_RELEASE_VERSION,
+            description=(
+                "Whether the route is health-checked. When false the route activates "
+                "immediately and the remaining fields are ignored."
+            ),
+        ),
+        default=False,
+    )
     interval: float = gql_field(description="Interval in seconds between health checks.")
     path: str = gql_field(description="Path to check for health status.")
     max_retries: int = gql_field(description="Maximum number of retries for health check.")
@@ -861,6 +871,13 @@ class PreStartActionInputGQL(PydanticInputMixin[PreStartActionDTO]):
     name="ModelHealthCheckInput",
 )
 class ModelHealthCheckInputGQL(PydanticInputMixin[ModelHealthCheckInputDTO]):
+    enable: bool = gql_field(
+        description=(
+            "Whether the route should be health-checked. When false the route activates "
+            "immediately and the remaining fields are ignored."
+        ),
+        default=False,
+    )
     interval: float | None = gql_field(
         description="Interval in seconds between health checks.", default=None
     )