Load balancer with control plane nodes only?

[tboerger]

I got a small cluster where control plane nodes also act as worker nodes, the load balancer gets created, but it doesn't have any target? Can somebody give me a hint how the load balancer takes the control plane nodes as a target?

[gris-gris]

up

[tboerger]

For those who came here for a solution, just set this feature gate within your hcloud ccm deployment and it will work: --feature-gates=LegacyNodeRoleBehavior=false

[mysticaltech]

@tboerger This seems to have been removed in the latest CCM (probably due to the upgrade of inner Kube libs that removes that in 1.22), as I get this error now:

Error: invalid argument "LegacyNodeRoleBehavior=false" for "--feature-gates" flag: unrecognized feature gate: LegacyNodeRoleBehavior
Usage:
  cloud-controller-manager [flags]

What is the new way of achieving the above?

[mysticaltech]

I would propose re-opening this issue, as it no longer works and is causing an issue with our project https://github.com/kube-hetzner/terraform-hcloud-kube-hetzner/issues/311; any help in solving this would be appreciated!

CC. @LKaemmerling 🙏

[tboerger]

Great that I haven't updated yet

[mysticaltech]

@tboerger, I feel that the feature-gates page holds the key to getting this to work with the new CCM; especially interesting seem the ServiceNodeExclusion feature gate.

It says:

ServiceNodeExclusion: Enable the exclusion of nodes from load balancers created by a cloud provider. A node is eligible for exclusion if labelled with "node.kubernetes.io/exclude-from-external-load-balancers".

From the above, I would deduce that with the new setup, the "master" / "control-plane" label is not looked at by the CCM to deal with LBs if the ServiceNodeExclusion is set to true. It will only exclude nodes if they have the "exclude-from-external-load-balancers" label.

What do you think? Now probably a good idea to test. I will do it as soon as I have some time for this.

[mysticaltech]

@tboerger The fix is just to remove this feature gate thing, it's just no longer needed all together! Updating to the latest CCM will just abide by the control-plane label by default, if you remove it on the control-plane nodes, those will show up as targets in LBs.

This can be closed for good!