ScyllaDB Docs ScyllaDB Operator Deploy ScyllaDB Before you deploy Set up dedicated node pools

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Set up dedicated node pools¶

ScyllaDB requires dedicated Kubernetes nodes to guarantee predictable performance. These nodes should not run any other workloads.

Why dedicate nodes to ScyllaDB¶

ScyllaDB is designed to consume all available CPU, memory, and I/O on its host. Sharing nodes with other workloads leads to:

Resource contention — noisy neighbours competing for CPU cycles and memory bandwidth cause unpredictable latency.
CPU pinning failures — the kubelet’s static CPU manager policy can only assign exclusive cores when the node is not overcommitted.
Incorrect performance tuning — NodeConfig tunes IRQ affinity, clocksource, and sysctls at the host level, affecting all Pods on the node.

Requirements¶

Dedicated ScyllaDB nodes must have:

Local NVMe storage — ScyllaDB stores data on local SSDs for maximum I/O performance. Use instance types with directly attached NVMe drives.
Sufficient CPU and memory — see the ScyllaDB system requirements for minimum and recommended specifications. Plan for at least 2 CPUs reserved for the OS, kubelet, and DaemonSets.
xfsprogs installed — NodeConfig formats local disks with XFS. The xfsprogs package must be available on the node OS image. Most managed Kubernetes distributions include it by default, but custom or minimal images may not.

Recommended instance types¶

Use n2-highmem or z3-highmem families with local SSDs. See GCE recommendations.

Use storage-optimized instances from the i family (e.g., i3en, i4i, i8g). See AWS recommendations.

Use DenseIO shapes. See OCI recommendations.

Instance type recommendations depend on the underlying cloud provider. Use the same instance families as the corresponding platform (e.g., i family on AWS for ROSA, n2-highmem on GCP for OSD). Configure node pools using MachineSets or MachinePools depending on your OpenShift variant.

Label the nodes¶

Apply the ScyllaDB node label so that Pod affinity rules can target these nodes:

kubectl label nodes <node-name> scylla.scylladb.com/node-type=scylla

When using managed Kubernetes services, apply the label at node pool creation time to avoid manual labeling:

gcloud container node-pools create flag:

--node-labels 'scylla.scylladb.com/node-type=scylla'

See the GKE cluster setup guide for a complete example.

eksctl create cluster configuration:

labels:
  scylla.scylladb.com/node-type: scylla

See the EKS cluster setup guide for a complete example.

oci ce node-pool create flag:

--initial-node-labels '[{"key": "scylla.scylladb.com/node-type", "value": "scylla"}]'

See the OKE cluster setup guide for a complete example.

Configure labels on your node pool using MachineSets or MachinePools depending on your OpenShift variant.

metadata:
  labels:
    scylla.scylladb.com/node-type: scylla

Taint the nodes¶

Apply a taint to prevent non-ScyllaDB workloads from being scheduled on the dedicated nodes:

kubectl taint nodes -l 'scylla.scylladb.com/node-type=scylla' \
  scylla-operator.scylladb.com/dedicated=scyllaclusters:NoSchedule --overwrite

The ScyllaCluster manifest must include a matching toleration, and the NodeConfig placement must tolerate the same taint. The reference deployments include both.

Note

The label scylla.scylladb.com/node-type: scylla and taint scylla-operator.scylladb.com/dedicated=scyllaclusters:NoSchedule are conventions used throughout the documentation and examples. You may use different values as long as you adjust all selectors, tolerations, and NodeConfig placements accordingly.

Verify the setup¶

# Check that nodes have the label
kubectl get nodes -l scylla.scylladb.com/node-type=scylla

# Verify the taint
kubectl get nodes -l scylla.scylladb.com/node-type=scylla \
  -o jsonpath='{range .items[*]}{.metadata.name}{"\t"}{.spec.taints}{"\n"}{end}'

# After deploying, confirm ScyllaDB Pods run only on dedicated nodes
kubectl get pods -l scylla/cluster=scylladb -o wide

Platform-specific guides¶

For end-to-end node pool creation on a specific platform, see the platform-specific cluster setup guides.

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