Node Groups

Overview

Node groups are named pools of worker nodes within a single Kubernetes cluster. Each group can have a different instance flavor, enabling heterogeneous clusters — e.g., a GPU node pool for machine learning workloads alongside a general-purpose pool for web services. Node groups are scaled independently, giving fine-grained control over capacity without affecting other workloads on the cluster.

Prerequisites

A cluster in CREATE_COMPLETE status
Sufficient compute quota for the new node group

Default Node Group

Every cluster has a default node group created at provisioning time. Its flavor and node count are set by the cluster template and the initial node count parameter. The default node group is named default-worker.

List node groups for a cluster

openstack coe nodegroup list prod-cluster-01

Create a Node Group

Dashboard
CLI

Navigate to the cluster

Navigate to Container > Clusters. Click your cluster name.

Open Node Groups

Click the Node Groups tab on the cluster detail page.

Create node group

Click Create Node Group and fill in the fields:

Field	Description	Example
Name	Unique name within the cluster	`gpu-workers`
Node Count	Initial number of nodes in the group	`2`
Flavor	Instance size for this group	`g1.xlarge`
Min Nodes	Minimum nodes for autoscaling	`1`
Max Nodes	Maximum nodes for autoscaling	`5`
Role	`worker` or `infra`	`worker`

Create

Click Create Node Group. Nodes are provisioned and join the cluster.

Node group appears in the list and nodes show STATUS: Ready in kubectl.

Create a GPU node group

openstack coe nodegroup create prod-cluster-01 \
  --name gpu-workers \
  --node-count 2 \
  --flavor g1.xlarge \
  --min-nodes 1 \
  --max-nodes 5 \
  --role worker

List all node groups

openstack coe nodegroup list prod-cluster-01

Show node group details

openstack coe nodegroup show prod-cluster-01 gpu-workers

Verify nodes are Ready in kubectl

kubectl get nodes -l ng=gpu-workers

New nodes appear in kubectl with STATUS: Ready.

Scale a Node Group

Dashboard
CLI

On the cluster detail page, click the Node Groups tab. Find the node group and click Actions → Resize. Enter the new node count and confirm.

Scale a node group

openstack coe nodegroup update prod-cluster-01 gpu-workers \
  replace node_count=4

Monitor scaling progress

openstack coe nodegroup show prod-cluster-01 gpu-workers \
  -f value -c status -c node_count

Wait for status to return to UPDATE_COMPLETE.

Use node groups for fine-grained scaling: scale GPU nodes up for batch jobs and back down when idle, without touching the general-purpose worker pool.

Schedule Workloads to a Specific Node Group

Use Kubernetes node selectors or taints and tolerations to target workloads to a specific node group.

spec:
  nodeSelector:
    node.kubernetes.io/instance-type: g1.xlarge

spec:
  tolerations:
    - key: "node-type"
      operator: "Equal"
      value: "gpu"
      effect: "NoSchedule"

Apply a taint to all nodes in a node group to ensure only workloads with the matching toleration are scheduled there:

Taint all GPU nodes

kubectl taint nodes -l ng=gpu-workers \
  node-type=gpu:NoSchedule

Delete a Node Group

Deleting a node group removes all nodes in the group and evicts all pods running on them. Ensure workloads have been migrated to other node groups before deletion.

Delete a node group

openstack coe nodegroup delete prod-cluster-01 gpu-workers

Next Steps

Scale Cluster

Resize the default node group for overall cluster capacity changes.

Cluster Upgrades

Upgrade Kubernetes version across all node groups.

Access Cluster

Configure kubectl to connect to your cluster and verify node readiness.

Troubleshooting

Resolve node group creation and scaling failures.

Core Services

Other Services

Overview

Default Node Group

Create a Node Group

Navigate to the cluster

Open Node Groups

Create node group

Create

Scale a Node Group

Schedule Workloads to a Specific Node Group

Delete a Node Group

Next Steps

Scale Cluster

Cluster Upgrades

Access Cluster

Troubleshooting

​Overview

​Default Node Group

​Create a Node Group

Navigate to the cluster

Open Node Groups

Create node group

Create

​Scale a Node Group

​Schedule Workloads to a Specific Node Group

​Delete a Node Group

​Next Steps

Scale Cluster

Cluster Upgrades

Access Cluster

Troubleshooting

Overview

Default Node Group

Create a Node Group

Scale a Node Group

Schedule Workloads to a Specific Node Group

Delete a Node Group

Next Steps