Load balance to bare-metal nodes

A Hetzner load balancer serves bare-metal (Robot) nodes exactly like Cloud nodes. The CCM handles both natively, so there is nothing extra to do for bare metal. Point a type: LoadBalancer Service at a pool that includes Robot servers and it works. The rest of this page explains how the CCM adds each kind and how the standard settings behave, so a mixed pool is easy to reason about.

Server targets and IP targets

The CCM adds the two machine kinds as different target types:

• Hetzner Cloud nodes join as server targets. The CCM references the cloud server by its ID, and Hetzner tracks it.
• Bare-metal (Robot) nodes join as IP targets. The CCM adds the Robot server by its public IPv4 address.

Both back the same type: LoadBalancer Service, so a mixed pool of Cloud and Robot nodes works, and the load balancer spreads traffic across both.

Bare-metal targets stay IPv4

By default the platform pins bare-metal targets to IPv4, with HCLOUD_LOAD_BALANCERS_ROBOT_TARGET_ADDRESS_FAMILY=ipv4 on the CCM. This is the same reason the rest of the cluster runs IPv4: nodes have no usable IPv6, so an IPv6 target would never pass its health check and would remain permanently unhealthy. On an IPv4-only cluster the default is the correct setting, and you leave it unchanged.

You can set the family per Service with the robot-target-address-family annotation:

		metadata:
  annotations:
    load-balancer.hetzner.cloud/robot-target-address-family: ipv4
	

Traffic policies on bare-metal servers

Service traffic policies behave identically on bare-metal and cloud nodes. For deep dives on how externalTrafficPolicy impacts packet hops and source IP preservation, see Preserve the client source IP .

When configuring externalTrafficPolicy: Local on bare-metal nodes:

• Schedule pods on all target servers: The load balancer will only route traffic to bare-metal servers running a ready replica. Ensure your pods are evenly distributed (or deployed via a DaemonSet) so physical servers do not sit idle.
• Tune health checks: See Tune health checks for node replacement to ensure fast target pool ejection during maintenance.

For why you would run bare metal at all, and how to add it, see Bare metal, cloud, and accelerators and Add bare-metal servers .