This is the authoritative reference for the ScaledObject configuration that drives the KubeMQ KEDA external scaler (kubemq/kubemq-keda-scaler:1.0.0). It documents every trigger metadata field, the scaler Service address, the two trigger types, the Helm values, and the example manifests the repo ships. For the metric's underlying meaning, see Queues; for the scaler's own process settings, see Environment variables.

Trigger metadata

Every field below is read from the metadata block of a KEDA external (or external-push) trigger and parsed by ParseScalerMetadata. Required fields produce an InvalidArgument gRPC error if absent; bounds are enforced on length and numeric range.

Parameter	Required	Default	Description
`kubemqAddress`	Yes	—	KubeMQ broker address in `host:port` form. Max 253 characters; the port must be `1`–`65535`. Parsed with `net.SplitHostPort`.
`queueName`	Yes	—	Queue channel name to monitor. Max 256 characters.
`targetWaiting`	No	`10`	Target `Waiting` messages per replica. Must be a finite, positive number.
`activationTargetWaiting`	No	`0`	Scale-from-zero threshold. The scaler reports active when `Waiting > activationTargetWaiting`. Must be a finite, non-negative number.
`authToken`	No	—	KubeMQ authentication token. Max 4096 characters. Supply via a `TriggerAuthentication` secret rather than inline.
`tls`	No	`false`	Enable a TLS connection to KubeMQ. Accepts `true`, `1`, or `yes` (case-insensitive) as true; anything else is false.
`certFile`	No	—	Path to a CA certificate file. Max 512 characters. Must resolve under `/certs/`, `/etc/ssl/`, or `/etc/pki/`, and must not contain `..` path traversal.
`serverOverrideDomain`	No	—	TLS server-name override (SNI) for the KubeMQ connection.

scalerAddress is consumed by KEDA itself (it tells KEDA where to reach the scaler) and is not part of the scaler's own metadata schema. The fields above are what the scaler parses from each RPC. The authToken, tls, certFile, serverOverrideDomain, and kubemqAddress values also form the connection-pool key, so distinct combinations get distinct pooled connections.

The numeric defaults and bounds are enforced, not advisory. A targetWaiting of 0, -1, NaN, or Inf is rejected with InvalidArgument, as is a non-numeric string. Always quote numeric values ("10", "5", "1") since trigger metadata is a string map.

scaled-object-basic.yaml

apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: kubemq-queue-scaler
spec:
  scaleTargetRef:
    name: my-queue-consumer
  pollingInterval: 15
  cooldownPeriod: 60
  minReplicaCount: 1
  maxReplicaCount: 10
  triggers:
    - type: external
      metadata:
        scalerAddress: kubemq-keda-scaler.default.svc.cluster.local:9090
        kubemqAddress: kubemq.default.svc.cluster.local:50000
        queueName: my-queue
        targetWaiting: "10"

Scaler Service address

The scalerAddress in your ScaledObject must resolve to the scaler's Kubernetes Service. Because the scaler runs as a ClusterIP service on port 9090, use the cluster-internal FQDN:

FQDN format

<service-name>.<namespace>.svc.cluster.local:9090

The service name follows the Helm release name. For a release named my-release installed into namespace keda:

Helm release example

my-release-kubemq-keda-scaler.keda.svc.cluster.local:9090

For the default Helm install (release name kubemq-keda-scaler in namespace default), the address is kubemq-keda-scaler.default.svc.cluster.local:9090.

Trigger types

KEDA supports two external trigger types against the same scaler. They differ only in how KEDA drives the scaler, not in what it measures. See Concepts for the model.

Type	Mode	Behavior
`external`	Poll-based (default)	KEDA calls `IsActive` and `GetMetrics` every `pollingInterval` seconds.
`external-push`	Push-based	KEDA opens a long-lived `StreamIsActive` stream. The scaler pushes active-status updates independently of `pollingInterval`. Use this for faster scale-from-zero detection.

scaled-object-scale-to-zero.yaml (external-push)

apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: scale-to-zero-scaler
spec:
  scaleTargetRef:
    name: batch-processor
  pollingInterval: 10
  cooldownPeriod: 120
  minReplicaCount: 0
  maxReplicaCount: 5
  triggers:
    - type: external-push
      metadata:
        scalerAddress: <SCALER_SERVICE>.<NAMESPACE>.svc.cluster.local:9090
        kubemqAddress: kubemq.default.svc.cluster.local:50000
        queueName: batch-jobs
        targetWaiting: "1"
        activationTargetWaiting: "0"

Helm values

The chart (kubemq-keda-scaler, chart version 1.0.0, app version 1.0.0) ships production-safe defaults: a hardened securityContext, modest resource bounds, and a ClusterIP service.

Value	Default	Description
`replicaCount`	`1`	Number of scaler pods.
`image.repository`	`kubemq/kubemq-keda-scaler`	Scaler image.
`image.tag`	`1.0.0`	Image tag.
`image.pullPolicy`	`IfNotPresent`	Image pull policy.
`service.type`	`ClusterIP`	Service type (cluster-internal by design).
`service.port`	`9090`	gRPC service port.
`env.grpcPort`	`9090`	Maps to `GRPC_PORT`.
`env.logLevel`	`info`	Maps to `LOG_LEVEL`.
`resources.requests`	`cpu: 50m`, `memory: 64Mi`	Resource requests.
`resources.limits`	`cpu: 200m`, `memory: 128Mi`	Resource limits.
`securityContext`	hardened (see below)	Pod/container security hardening.
`extraVolumes`	`[]`	Extra volumes (e.g. a TLS CA secret).
`extraVolumeMounts`	`[]`	Extra volume mounts (e.g. mount the CA at `/certs`).

values.yaml (securityContext)

securityContext:
  runAsNonRoot: true
  runAsUser: 65532
  allowPrivilegeEscalation: false
  readOnlyRootFilesystem: true
  capabilities:
    drop:
      - ALL

Because readOnlyRootFilesystem is true and the container runs as UID 65532, any TLS CA you mount via extraVolumes / extraVolumeMounts must land under one of the allowed certFile prefixes (/certs/, /etc/ssl/, /etc/pki/) and be readable by that user. See TLS and Authentication for the full flow.

Example manifests

The deploy/examples/ directory contains ready-to-use manifests. Apply them in the order below, honoring each file's prerequisites. Replace the <SCALER_SERVICE> and <NAMESPACE> placeholders with your actual scaler Service name and namespace.

File	Description	Prerequisites
`trigger-auth.yaml`	`TriggerAuthentication` plus the referenced `Secret`.	Create or edit the `Secret` token first.
`scaled-object-basic.yaml`	Basic queue autoscaling (`external`).	—
`scaled-object-ml-inference.yaml`	GPU inference with scale-to-zero and `fallback`.	—
`scaled-object-scale-to-zero.yaml`	Push-mode (`external-push`) scale-to-zero.	—
`scaled-object-tls-auth.yaml`	TLS plus auth token.	`trigger-auth.yaml` applied first.
`scaled-job.yaml`	`ScaledJob` — one `Job` per batch of messages.	—

trigger-auth.yaml

apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: kubemq-trigger-auth
spec:
  secretTargetRef:
    - parameter: authToken
      name: kubemq-auth-secret
      key: token
---
apiVersion: v1
kind: Secret
metadata:
  name: kubemq-auth-secret
type: Opaque
stringData:
  token: "your-kubemq-auth-token"

scaled-job.yaml

apiVersion: keda.sh/v1alpha1
kind: ScaledJob
metadata:
  name: kubemq-batch-job
spec:
  jobTargetRef:
    template:
      spec:
        containers:
          - name: worker
            image: my-batch-worker:latest
            env:
              - name: KUBEMQ_ADDRESS
                value: kubemq.default.svc.cluster.local:50000
              - name: QUEUE_NAME
                value: batch-queue
        restartPolicy: Never
    backoffLimit: 3
  pollingInterval: 10
  maxReplicaCount: 50
  successfulJobsHistoryLimit: 5
  failedJobsHistoryLimit: 3
  triggers:
    - type: external
      metadata:
        scalerAddress: <SCALER_SERVICE>.<NAMESPACE>.svc.cluster.local:9090
        kubemqAddress: kubemq.default.svc.cluster.local:50000
        queueName: batch-queue
        targetWaiting: "1"

Environment variables — the scaler process settings.
gRPC RPCs — the ExternalScaler RPC surface, retry, and health checks.
Error codes — the KubeMQ-error-to-gRPC mapping and KEDA fallback.

ScaledObject Metadata

Trigger metadata

Scaler Service address

Trigger types

Helm values

Example manifests

On this page

ScaledObject Metadata

Trigger metadata

Scaler Service address

Trigger types

Helm values

Example manifests

Related

On this page