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Create a Liquid Metal cluster

We will use clusterctl again to generate a manifest for our workload cluster.

Configure​

First, we need to configure some options:

export CLUSTER_NAME=lm-demo
export CONTROL_PLANE_MACHINE_COUNT=1
export WORKER_MACHINE_COUNT=5

This will result in a cluster with a single control plane, and 5 worker nodes. You may change these values to whatever you wish.

CAPMVM will use kube-vip to assign a virtual IP to our Liquid Metal cluster. Choose an address from outside the range we set as the dhcp pool back in the Prep the network section. In my case I did not make any changes to the XML example file, so I will use 192.168.100.9.

export CONTROL_PLANE_VIP="192.168.100.9" # update to suit your network

Lastly we set the address that the flintlockd service we started earlier is listening on. We set the address to 0.0.0.0, so the endpoint here will be the internal IP of the machine you are running on attached to the default interface. You can discover this with either hostname -I or ip link ls. In my case this is 192.168.1.130.

export HOST_ENDPOINT="192.168.1.130:9090" # don't forget to include the port!

Generate​

Now we can use clusterctl to generate a cluster manifest:

clusterctl generate cluster -i microvm:$CAPMVM_VERSION -f cilium $CLUSTER_NAME > cluster.yaml

We need to edit the file to change the network mode for the created MicroVMs. You'll recall that one of the reasons we created our own network was so that MicroVMs can be accessed from the same machine they were created on. To do this we need to ensure that MicroVMs are created with the correct network interface type.

This can be configured on the MicrovmMachineTemplate spec at spec.template.spec.networkInterfaces[0].type. There will be 2 instances of MicrovmMachineTemplate, one named lm-demo-control-plane and the other lm-demo-md-0. Change both types for the eth1 network interface from macvtap to tap.

Expand to see required file changes
...
---
apiVersion: infrastructure.cluster.x-k8s.io/v1alpha1
kind: MicrovmMachineTemplate
metadata:
  name: lm-demo-control-plane
  namespace: default
spec:
  template:
    spec:
      kernel:
        filename: boot/vmlinux
        image: ghcr.io/weaveworks-liquidmetal/flintlock-kernel:5.10.77
      kernelCmdline: {}
      memoryMb: 2048
      networkInterfaces:
      - guestDeviceName: eth1
        type: tap # <- this should be tap
...
---
apiVersion: infrastructure.cluster.x-k8s.io/v1alpha1
kind: MicrovmMachineTemplate
metadata:
  name: lm-demo-md-0
  namespace: default
spec:
  template:
    spec:
      kernel:
        filename: boot/vmlinux
        image: ghcr.io/weaveworks-liquidmetal/flintlock-kernel:5.10.77
      kernelCmdline: {}
      memoryMb: 2048
      networkInterfaces:
      - guestDeviceName: eth1
        type: tap # <- this should be tap
...

Once you have made those changes, save and close the file.

Apply​

Once you are happy with the manifest, use kubectl to apply it to your management cluster:

kubectl apply -f cluster.yaml
Output
cluster.cluster.x-k8s.io/lm-demo created
microvmcluster.infrastructure.cluster.x-k8s.io/lm-demo created
kubeadmcontrolplane.controlplane.cluster.x-k8s.io/lm-demo-control-plane created
microvmmachinetemplate.infrastructure.cluster.x-k8s.io/lm-demo-control-plane created
machinedeployment.cluster.x-k8s.io/lm-demo-md-0 created
microvmmachinetemplate.infrastructure.cluster.x-k8s.io/lm-demo-md-0 created
kubeadmconfigtemplate.bootstrap.cluster.x-k8s.io/lm-demo-md-0 created
clusterresourceset.addons.cluster.x-k8s.io/crs-cilium created
configmap/cilium-addon created

Use​

After a moment, you can fetch the MicroVMs workload cluster's kubeconfig from your management cluster. This kubeconfig is written to a secret by CAPI:

kubectl get secret $CLUSTER_NAME-kubeconfig -o json | jq -r .data.value | base64 -d > config.yaml

With that kubeconfig we can target the Liquid Metal cluster with kubectl:

kubectl --kubeconfig config.yaml get nodes
tip

This may not return anything for a few moments; we need to wait for the MicroVMs to start and for the cluster control-plane to then be bootstrapped. Prepend the command with watch and eventually (<=5m) you will see the errors stop and the cluster come up.

An expected error for the first 2-3 minutes is:

Unable to connect to the server: dial tcp 192.168.100.9:6443: connect: no route to host
Output
NAME                          STATUS   ROLES                  AGE     VERSION
lm-demo-control-plane-hdpkj   Ready    control-plane,master   4m35s   v1.21.8
lm-demo-md-0-9444f            Ready    <none>                 3m41s   v1.21.8
lm-demo-md-0-bdqwj            Ready    <none>                 3m43s   v1.21.8
lm-demo-md-0-gfgbq            Ready    <none>                 3m41s   v1.21.8
lm-demo-md-0-pxkk6            Ready    <none>                 3m41s   v1.21.8
lm-demo-md-0-qpzwn            Ready    <none>                 3m43s   v1.21.8

Continue to the next page to learn how to inspect the environment and see what a Liquid Metal Platform and Cluster look like in action.