Scale Up/Down

This guide covers scaling your cluster at both the infrastructure and Kubernetes levels.

Scale Infrastructure

Add worker nodes

1. Edit terraform.tfvars – update worker_node_types:

   worker_node_types = [
     { type = "cx23", count = 2 },
     { type = "cx33", count = 1 },  # 3 workers total, mixed types
   ]
   

2. Apply changes:

   tofu apply
   

3. Regenerate Ansible inventory:

   ./scripts/generate-ansible-inventory.sh
   

4. Run Ansible playbooks on the new nodes – see Server Management (Ansible) for the full workflow.

Add replica control nodes

Same pattern using control_node_types:

control_node_types = [
  { type = "cx23", count = 2 },  # 2 replicas → 3 total control nodes
]

Then tofu apply, regenerate inventory, and run Ansible playbooks.

Remove nodes

1. Drain and remove from Kubernetes first (see Remove nodes from Kubernetes below)
2. Update terraform.tfvars to reduce node counts
3. Run tofu apply

Scale Kubernetes

Join new worker nodes

After provisioning and running Ansible playbooks on new nodes, join them to the cluster. Follow Step 2 of the Kubernetes guide to run the kubeadm join command.

Remove nodes from Kubernetes

Before removing infrastructure, drain and delete the node from Kubernetes:

kubectl drain <node-name> --ignore-daemonsets --delete-emptydir-data
kubectl delete node <node-name>

Then update terraform.tfvars and run tofu apply to remove the infrastructure.

Examples

Master-only (no replicas, no workers)

# terraform.tfvars
master_control_node_type = "cx23"
control_node_types = []
worker_node_types  = []

Add 2 workers

# terraform.tfvars
worker_node_types = [
  { type = "cx23", count = 2 },
]

Mixed server types

# terraform.tfvars
control_node_types = [
  { type = "cx23", count = 2 },
]
worker_node_types = [
  { type = "cx23", count = 2 },
  { type = "cx33", count = 1 },
]