EngineClass configuration inheritance

A FireboltEngineClass provides reusable defaults to Engines in the same namespace. Set FireboltEngine.spec.engineClassRef to the class name. Values resolve in this order:

The Engine value
The referenced EngineClass value
The Firebolt Operator default

An EngineClass is namespaced because its pod template can reference namespaced resources such as ServiceAccounts, Secrets, ConfigMaps, and persistent volume claims.

Pod template precedence

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

Field	Resolution
`serviceAccountName`	Engine, then class
`nodeSelector`	Maps merge; Engine keys win
`tolerations`, `topologySpreadConstraints`, `imagePullSecrets`	Class entries followed by Engine entries
`affinity`, pod `securityContext`	Engine value replaces class value when set
labels and annotations	Maps merge; Engine keys win; `firebolt.io/` keys are reserved
volumes	Class entries followed by Engine entries; Firebolt Operator volume names are reserved
init containers and sidecars	Class entries followed by Engine entries
Engine container image and pull policy	Engine, then class, then Firebolt Operator default
Engine container resources	The Engine block replaces the class block when the Engine sets requests, limits, or claims
Engine container environment and mounts	Firebolt Operator entries, then class 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 the class backend applies; default is `emptyDir`.
`customEngineConfig`	Deep merge: Firebolt Operator configuration, class configuration, then Engine configuration. Engine keys win. Protected identity, routing, and topology paths cannot be overridden.
`rollout`	Engine, class, then `graceful`
`drainCheckEnabled`	Engine, class, then `true`
`drainCheckInterval`	Engine, class, then Firebolt Operator default
`autoStop`	Whole setting. The Engine policy replaces the class policy when set.
`uiSidecar`	Engine, class, then `false`

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. 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.

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API reference

Legal

Pod template precedence

Override a class image for one Engine

Inherited Engine settings

Class changes

Delete a class

​Pod template precedence

​Override a class image for one Engine

​Inherited Engine settings

​Class changes

​Delete a class

Pod template precedence

Override a class image for one Engine

Inherited Engine settings

Class changes

Delete a class