Cluster Templates

Overview

Cluster templates are reusable blueprints that define the configuration for Kubernetes clusters. A template captures the Kubernetes version, node image, instance flavor, network driver, and storage backend. Once created, a template can be used to deploy multiple clusters with consistent configurations. Your administrator can publish public templates shared across all projects; you can also create private templates for your own use.

Prerequisites

An active Polystack account with project access
A keypair created in your project for node SSH access
Compute quota sufficient for cluster nodes
A project network with external access

Template Fields Reference

Field	Required	Description	Recommended Value
Name	Yes	Unique template identifier	`k8s-1.29-prod`
Container Infra Driver	Yes	Cluster provisioning engine	`kubernetes`
Image	Yes	Boot image for cluster nodes	`fedora-coreos-39`
Keypair	Yes	SSH key for node access	Your project keypair
Flavor	Yes	Instance size for worker nodes	`m1.large` (4 vCPU / 8 GB)
Master Flavor	Yes	Instance size for master nodes	`m1.xlarge` (8 vCPU / 16 GB)
Network Driver	Yes	Container network interface	`calico` (production)
Volume Driver	Yes	Persistent volume backend	`cinder`
External Network	Yes	Floating IP source	`public`
DNS Nameserver	Yes	Resolver for cluster nodes	`8.8.8.8`
Master LB Enabled	No	Load balance master nodes	`True` (HA)
Docker Volume Size	No	Container storage per node (GB)	`50`
Floating IP Enabled	No	Assign floating IPs to nodes	`True`

Create a Cluster Template

Dashboard
CLI

Navigate to Cluster Templates

Navigate to Container > Cluster Templates.

Create the template

Click Create Cluster Template and fill in the required fields using the reference table above.

For production clusters, enable Master LB to place a load balancer in front of master nodes and set Master Count to 3 when deploying the cluster.

Configure advanced options

Expand Advanced to set optional parameters:

Insecure Registry: Internal container registry URL (if used)
Fixed Network / Subnet: Pin cluster nodes to a specific project network
Labels: Key-value labels for platform-specific options (e.g., auto_healing_enabled=true)

Save the template

Click Create Cluster Template. The template appears in the list with status ACTIVE.

Template created with status ACTIVE and visible in the template list.

Authenticate

Load credentials

source openrc.sh

Create the template

Create cluster template

openstack coe cluster template create k8s-1.29-prod \
  --coe kubernetes \
  --image fedora-coreos-39 \
  --keypair my-keypair \
  --flavor m1.large \
  --master-flavor m1.xlarge \
  --network-driver calico \
  --volume-driver cinder \
  --external-network public \
  --dns-nameserver 8.8.8.8 \
  --docker-volume-size 50 \
  --master-lb-enabled \
  --labels auto_healing_enabled=true

Verify the template

List templates

openstack coe cluster template list

Show template details

openstack coe cluster template show k8s-1.29-prod

Template shows coe_version populated and no error messages.

Network Driver Comparison

The network driver (CNI plugin) is configured at template creation and cannot be changed after cluster deployment.

Driver	Network Policy	Performance	Recommended For
`calico`	Full NetworkPolicy enforcement	Moderate	Production workloads requiring pod isolation
`flannel`	None	Higher (simpler overlay)	Development and test clusters

Use calico for all production templates. Flannel is appropriate only for isolated test environments where Kubernetes NetworkPolicy is not required.

Manage Existing Templates

Dashboard
CLI

Navigate to Container > Cluster Templates. From this view you can:

Click a template name to view its full configuration
Click Actions → Delete to remove unused templates (templates in use by clusters cannot be deleted)

List all templates

openstack coe cluster template list

Show a template

openstack coe cluster template show <template-name>

Update a template field

openstack coe cluster template update <template-name> \
  replace dns_nameserver=1.1.1.1

Delete a template

openstack coe cluster template delete <template-name>

Templates referenced by active clusters cannot be deleted. Delete all clusters using the template before removing it.

Next Steps

Deploy a Cluster

Provision a Kubernetes cluster from your template in minutes.

Node Groups

Add specialized node pools with different flavors to your cluster.

Access Cluster

Download kubeconfig and connect kubectl to your cluster.

Kubernetes Admin Guide

Administrator reference for managing public templates and quotas.

Core Services

Other Services

Overview

Template Fields Reference

Create a Cluster Template

Navigate to Cluster Templates

Create the template

Configure advanced options

Save the template

Authenticate

Create the template

Verify the template

Network Driver Comparison

Manage Existing Templates

Next Steps

Deploy a Cluster

Node Groups

Access Cluster

Kubernetes Admin Guide

​Overview

​Template Fields Reference

​Create a Cluster Template

Navigate to Cluster Templates

Create the template

Configure advanced options

Save the template

Authenticate

Create the template

Verify the template

​Network Driver Comparison

​Manage Existing Templates

​Next Steps

Deploy a Cluster

Node Groups

Access Cluster

Kubernetes Admin Guide

Overview

Template Fields Reference

Create a Cluster Template

Network Driver Comparison

Manage Existing Templates

Next Steps