EngineClass configuration inheritance

Set FireboltEngine.spec.engineClassRef to a class name. The Firebolt Operator resolves that name namespaced-first: a FireboltEngineClass in the Engine’s namespace if present, otherwise a ClusterFireboltEngineClass of the same name. Same name in both scopes is allowed; the namespaced object is the override and wins wholesale. Values resolve in this order:

The Engine value
The namespace FireboltEnginePreset value, when one object exists
The resolved class value (FireboltEngineClass, else ClusterFireboltEngineClass)
The Firebolt Operator default

FireboltEngineClass is namespaced because its pod template can reference namespaced resources such as ServiceAccounts, Secrets, ConfigMaps, and persistent volume claims. ClusterFireboltEngineClass is SKU-only: instance type, resources, affinity/tolerations, init containers, and an optional engine image. It does not carry ServiceAccount names, Secret refs, IAM annotations, ConfigMap refs, persistentVolumeClaim volumes, resource claims, storage, rollout, drain-check, autoStop, or uiSidecar. Those stay on the namespaced class, Preset, or Engine spec. A cluster-scoped object has no namespace of its own, so any of those references would bind to whatever happens to exist in each consuming namespace. The same catalog entry would then render differently per namespace, or not at all. The admission webhook and the Engine reconciler both reject them. Volume sources that name nothing, such as emptyDir and downwardAPI, stay allowed, as do ephemeral claim templates, which create a fresh claim in the consuming namespace from a cluster-scoped StorageClass. An ephemeral claim template must not set dataSource or dataSourceRef: those seed the new claim from a claim or snapshot resolved in the consuming namespace, which is the per-namespace binding the rule exists to prevent.

Pod template precedence

The Engine template overrides Preset, and Preset overrides the class, for conflicting scalar values. Collection behavior depends on the field:

Field	Resolution
`serviceAccountName`	Engine, then Preset, then class
`nodeSelector`	Maps merge; Engine keys win over Preset keys, which win over class keys
`tolerations`, `topologySpreadConstraints`, `imagePullSecrets`	Class entries, then Preset entries, then Engine entries
`affinity`, pod `securityContext`	Engine value replaces Preset, which replaces class, when set
labels and annotations	Maps merge; Engine keys win; `firebolt.io/` keys are reserved
volumes	Class entries, then Preset entries, then Engine entries; Firebolt Operator volume names are reserved
init containers and sidecars	Class entries, then Preset entries, then Engine entries
Engine container image and pull policy	Engine, then Preset, then class, then Firebolt Operator default
Engine container resources	The Engine block replaces the Preset or class block when the Engine sets requests, limits, or claims
Engine container environment and mounts	Firebolt Operator entries, then class entries, then Preset entries, then Engine entries; reserved names are rejected or omitted

The Firebolt Operator owns fields required for Engine identity, networking, probes, and StatefulSet behavior. See the FireboltEngineClass CRD reference for the complete allowed-field table.

Override a class image for one Engine

Use the class image as the shared default:

apiVersion: compute.firebolt.io/v1alpha1
kind: FireboltEngineClass
metadata:
  name: production
  namespace: firebolt
spec:
  template:
    spec:
      containers:
        - name: engine
          image: example.com/firebolt/engine:stable

Override it on one Engine:

apiVersion: compute.firebolt.io/v1alpha1
kind: FireboltEngine
metadata:
  name: canary
  namespace: firebolt
spec:
  instanceRef: production
  engineClassRef: production
  replicas: 1
  template:
    spec:
      containers:
        - name: engine
          image: example.com/firebolt/engine:candidate

Inherited Engine settings

Field	Resolution
`storage`	Whole setting. The Engine backend wins when set; otherwise Preset; otherwise the class; default is `emptyDir`.
`customEngineConfig`	Deep merge: Firebolt Operator configuration, class configuration, Preset configuration, then Engine configuration. Engine keys win. Protected identity, routing, and topology paths cannot be overridden.
`rollout`	Engine, class, then `graceful`. Preset does not carry this field.
`drainCheckEnabled`	Engine, class, then `true`. Preset does not carry this field.
`drainCheckInterval`	Engine, class, then Firebolt Operator default. Preset does not carry this field.
`autoStop`	Whole setting. The Engine policy replaces the class policy when set. Preset does not carry this field.
`uiSidecar`	Engine, class, then `false`. Preset does not carry this field.

FireboltEnginePreset

FireboltEnginePreset is an optional ambient overlay in the same namespace. Engines do not reference it by name. The object must be named firebolt — a validation rule baked into the CRD pins the name, so name uniqueness caps a namespace at one object. Set spec.requirePreset: true on an Engine to keep it from becoming Ready until that object exists and is Ready. A present but unready Preset object fails closed for every Engine in the namespace even when requirePreset is unset. See FireboltEnginePreset overview.

Class changes

Changes to class settings that alter Engine pods roll every bound Engine in the namespace. These include the pod template, storage, custom Engine configuration, and UI sidecar setting. A FireboltEnginePreset edit to the pod template, storage, or custom Engine configuration rolls every Engine in the namespace. Changes to rollout, drain-check, and auto-stop policy take effect without forcing a pod rollout by themselves. Inspect the number of referencing Engines with:

kubectl get firengc production -n firebolt

Delete a class

Class deletion remains blocked while Engines in the same namespace reference it. Remove or replace spec.engineClassRef on every bound Engine, wait for those updates to reconcile, then delete the class. If deletion is blocked, status.conditions[type=Ready] reports reason DeletionBlocked and status.boundEngines shows the current consumer count. ClusterFireboltEngineClass delete is not blocked. Engines that still name the SKU emit a Warning EngineClassNotFound Event and keep running the last applied pods until the catalog object is restored or spec.engineClassRef is changed.

Overview

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Guides

SQL reference

Release notes

API reference

Legal

Pod template precedence

Override a class image for one Engine

Inherited Engine settings

FireboltEnginePreset

Class changes

Delete a class

​Pod template precedence

​Override a class image for one Engine

​Inherited Engine settings

​FireboltEnginePreset

​Class changes

​Delete a class

Pod template precedence

Override a class image for one Engine

Inherited Engine settings

FireboltEnginePreset

Class changes

Delete a class