Configure your clusters to use OpenStack

GKE on Bare Metal supports the OpenStack Kubernetes Cloud provider. Use this feature to automatically provision OpenStack Load Balancing as a Service (LBaaS) resources. Those resources can replace the MetalLB resources to easily expose services running on your Anthos on bare metal clusters to other OpenStack tenants or outside the OpenStack network.

Before you begin

Decide the Anthos clusters that need to use OpenStack LBaaS resources.

Ensure you have access to the machines you are trying to configure.

Learn more about running the cloud-controller-manager in the Kubernetes documentation.

Change your clusters' configuration file

The OpenStack Kubernetes Cloud Provider requires that kubelet runs on all the nodes with the following argument:

cloud-provider: "external"

To ensure your Anthos clusters easily meet this requirement, add the baremetal.cluster.gke.io/external-cloud-provider: "true" annotation to your clusters' configuration file under the metadata section before initializing them.

The entry in your configuration file should look like the following example:

apiVersion: baremetal.cluster.gke.io/v1
kind: Cluster
metadata:
  name: cluster1
  namespace: cluster-cluster1
  annotations:
    baremetal.cluster.gke.io/external-cloud-provider: "true"
spec:
  ..

Some cloud providers on other cloud platforms require a special format for providerID, GKE on Bare Metal will generate a providerID for each machine. The format is like baremetal://MACHINE_ADDRESS. If you want to have a different providerID, you can specify one for each node along with the IP address. The configuration will look like:

 apiVersion: baremetal.cluster.gke.io/v1
 kind: Cluster
 metadata:
   name: cluster1
   namespace: cluster-cluster1
 spec:
   clusterNetwork:
     pods:
       cidrBlocks:
       - 192.168.0.0/16
     services:
       cidrBlocks:
       - 10.96.0.0/20
   controlPlane:
     nodePoolSpec:
       nodes:
       - address: 10.200.0.1
+        providerID: some-prefix://unique-string
       - address: 10.200.0.2
+        providerID: some-prefix2://unique-string2
  ...

---
 apiVersion: baremetal.cluster.gke.io/v1
 kind: NodePool
 metadata:
   name: nodepool1
   namespace: cluster-admin1
 spec:
   clusterName: admin1
   nodes:
   - address: 172.18.0.2
+    providerID: some-prefix3://unique-string3

After you edit the configuration file, use the following command to initialize your cluster:

bmctl create cluster -c cluster1

Now, all nodes in cluster1 run with the required argument: cloud-provider: "external"

All nodes also have the following fields added to their configuration files:

taints:
- effect: NoSchedule
  key: node.cloudprovider.kubernetes.io/uninitialized
  value: "true"

These fields are removed after you initialize your cloud provider on this cluster.

kubelet will run with your provided providerID if you specified one for this node.