Cluster Templates

AerospikeClusterTemplate lets you define reusable configuration profiles for Aerospike clusters. Instead of repeating the same scheduling, storage, and Aerospike configuration across every cluster, you define it once in a template and reference it from multiple clusters.

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When to use templates

• Multiple environments — define dev/stage/prod templates with different resource sizes and anti-affinity levels
• Organizational defaults — enforce storage class, tolerations, and heartbeat settings across teams
• Configuration standardization — prevent configuration drift by keeping shared settings in one place

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Create a template

Templates can now supply the container image, cluster size, monitoring sidecar, and network policy as defaults — in addition to the existing scheduling, storage, and Aerospike configuration fields.

apiVersion: acko.io/v1alpha1
kind: AerospikeClusterTemplate
metadata:
  name: hard-rack
  # AerospikeClusterTemplate is cluster-scoped (no namespace)
spec:
  # Standardize the Aerospike image and default cluster size across all hard-rack clusters
  image: aerospike:ce-8.1.1.1
  size: 6

  # Enable Prometheus monitoring sidecar by default
  monitoring:
    enabled: true
    port: 9145
    resources:
      requests:
        cpu: 50m
        memory: 64Mi
      limits:
        cpu: 200m
        memory: 128Mi
    serviceMonitor:
      enabled: true
      interval: 30s

  # Default network access policy
  aerospikeNetworkPolicy:
    accessType: pod
    alternateAccessType: pod
    fabricType: pod

  scheduling:
    podAntiAffinityLevel: required   # one Aerospike pod per node
    tolerations:
      - key: "aerospike"
        operator: "Exists"
        effect: "NoSchedule"

  storage:
    storageClassName: local-path
    localPVRequired: true
    resources:
      requests:
        storage: 100Gi

  resources:
    requests:
      cpu: "2"
      memory: "4Gi"
    limits:
      cpu: "2"
      memory: "4Gi"

  aerospikeConfig:
    service:
      proto-fd-max: 15000
    namespaceDefaults:
      replication-factor: 2
      data-size: 2147483648   # 2 GiB

kubectl apply -f config/samples/acko_v1alpha1_template_prod.yaml   # hard-rack

---

Reference a template from a cluster

When a template supplies image and size, the cluster can omit those fields entirely:

apiVersion: acko.io/v1alpha1
kind: AerospikeCluster
metadata:
  name: hard-rack-cluster
spec:
  # image and size are supplied by the "hard-rack" template (image: aerospike:ce-8.1.1.1, size: 6)
  templateRef:
    name: hard-rack

  aerospikeConfig:
    namespaces:
      - name: data
        storage-engine:
          type: memory

Since AerospikeClusterTemplate is cluster-scoped, you only need the template name — no namespace qualifier is required:

spec:
  templateRef:
    name: hard-rack

You can still set spec.image or spec.size explicitly on the cluster to override the template:

spec:
  image: aerospike:ce-8.1.1.1   # override: pin a specific image
  size: 3                         # override: use 3 nodes instead of the template's 6
  templateRef:
    name: hard-rack

The operator resolves the template at creation time and stores the spec in status.templateSnapshot. From that point the cluster operates independently — changes to the template do not automatically affect this cluster.

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Override template fields

Use spec.overrides to change specific fields without creating a new template:

spec:
  templateRef:
    name: hard-rack
  overrides:
    resources:
      requests:
        cpu: "4"
        memory: "8Gi"
      limits:
        cpu: "4"
        memory: "8Gi"
    scheduling:
      podAntiAffinityLevel: preferred   # relax anti-affinity for this cluster

Merge priority: overrides > template.spec > operator defaults

For maps (like aerospikeConfig.service), merging is recursive — only specified keys are overridden. For arrays (like tolerations) and scalar fields, the override replaces the template value entirely.

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Resync after template update

After updating a template, existing clusters show status.templateSnapshot.synced: false and emit a TemplateDrifted warning event. They continue operating on their snapshot.

To apply the updated template to a cluster:

kubectl annotate aerospikecluster hard-rack-cluster acko.io/resync-template=true

The operator will:

1. Re-fetch the template
2. Update status.templateSnapshot
3. Emit a TemplateApplied event
4. Remove the annotation

---

Check template snapshot status

kubectl get aerospikecluster hard-rack-cluster -o jsonpath='{.status.templateSnapshot}'

Example output:

{
  "name": "hard-rack",
  "resourceVersion": "12345",
  "snapshotTimestamp": "2026-03-01T10:00:00Z",
  "synced": true
}

---

Sample templates

The config/samples/ directory includes three ready-to-use template tiers:

	minimal	soft-rack	hard-rack
Purpose	Dev / quick-start	Staging	Production
size	1	3 (inherits)	6
anti-affinity	none	preferred	required
storage	standard 1 Gi	standard 10 Gi	local-path 100 Gi
rack guarantee	none	soft (same node OK)	hard (1 node : 1 rack)
resources	100 m / 256 Mi	500 m / 1 Gi	2 / 4 Gi (Guaranteed QoS)
monitoring	disabled	disabled	enabled
RF	1	2	2

Files:

• acko_v1alpha1_template_dev.yaml — minimal
• acko_v1alpha1_template_stage.yaml — soft-rack
• acko_v1alpha1_template_prod.yaml — hard-rack
• aerospike-cluster-with-template.yaml — example clusters using the templates

kubectl apply -f config/samples/acko_v1alpha1_template_prod.yaml   # hard-rack
kubectl apply -f config/samples/aerospike-cluster-with-template.yaml

---

Install via Helm

Use the defaultTemplates.enabled=true option to automatically create all three template tiers in the release namespace:

helm install aerospike-ce-kubernetes-operator oci://ghcr.io/kimsoungryoul/charts/aerospike-ce-kubernetes-operator \
  -n aerospike-operator --create-namespace \
  --set certManagerSubchart.enabled=true \
  --set defaultTemplates.enabled=true

Verify the templates are created:

kubectl get aerospikeclustertemplate
# NAME         AGE
# minimal      10s
# soft-rack    10s
# hard-rack    10s

Reference a template in your cluster:

apiVersion: acko.io/v1alpha1
kind: AerospikeCluster
metadata:
  name: my-cluster
spec:
  templateRef:
    name: soft-rack
  aerospikeConfig:
    namespaces:
      - name: data
        storage-engine:
          type: memory