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API load balancer

Two small VMs run HAProxy and Keepalived. OpenTofu downloads an Ubuntu 24.04 cloud image and configures the VMs with Proxmox cloud-init. HAProxy checks /readyz on each control plane node over HTTPS and routes only to nodes that respond. Keepalived advertises a virtual IP used by the Domain Name System (DNS) record api.<cluster-domain>.

Configuration​

Add the virtual IP and load balancer nodes in config.auto.tfvars.

network = {
  api_lb_vip = "10.25.150.9"
}

lb_nodes = {
  lb-00 = {
    host_node   = "host3"
    ip          = "10.25.150.5"
    mac_address = "bc:24:11:aa:aa:05"
    vm_id       = 8005
  }
  lb-01 = {
    host_node   = "host3"
    ip          = "10.25.150.6"
    mac_address = "bc:24:11:aa:aa:06"
    vm_id       = 8006
  }
}

Create a Domain Name System (DNS) A record api.<cluster-domain> pointing at api_lb_vip.

Verification​

After planning the infrastructure, verify the API responds.

curl -k "https://api.<cluster-domain>:6443/readyz"

The command prints ok when the API is ready.