51 Downstream cluster provisioning with Directed network provisioning (single-node) #

This section describes the workflow used to automate the provisioning of a single-node downstream cluster using directed network provisioning. This is the simplest way to automate the provisioning of a downstream cluster.

Requirements

The image generated using EIB, as described in the previous section (Chapter 49, Prepare downstream cluster image for connected scenarios), with the minimal configuration to set up the downstream cluster has to be located in the management cluster exactly on the path you configured on this section (Note).
The management server created and available to be used on the following sections. For more information, refer to the Management Cluster section Part V, “Setting up the management cluster”.

Workflow

The following diagram shows the workflow used to automate the provisioning of a single-node downstream cluster using directed network provisioning:

There are two different steps to automate the provisioning of a single-node downstream cluster using directed network provisioning:

Enroll the bare-metal host to make it available for the provisioning process.
Provision the bare-metal host to install and configure the operating system and the Kubernetes cluster.

Enroll the bare-metal host

The first step is to enroll the new bare-metal host in the management cluster to make it available to be provisioned. To do that, the following file (bmh-example.yaml) has to be created in the management cluster, to specify the BMC credentials to be used and the BaremetalHost object to be enrolled:

apiVersion: v1
kind: Secret
metadata:
  name: example-demo-credentials
type: Opaque
data:
  username: ${BMC_USERNAME}
  password: ${BMC_PASSWORD}
---
apiVersion: metal3.io/v1alpha1
kind: BareMetalHost
metadata:
  name: example-demo
  labels:
    cluster-role: control-plane
spec:
  architecture: x86_64
  online: true
  bootMACAddress: ${BMC_MAC}
  rootDeviceHints:
    deviceName: /dev/nvme0n1
  bmc:
    address: ${BMC_ADDRESS}
    disableCertificateVerification: true
    credentialsName: example-demo-credentials

where:

${BMC_USERNAME} — The user name for the BMC of the new bare-metal host.
${BMC_PASSWORD} — The password for the BMC of the new bare-metal host.
${BMC_MAC} — The MAC address of the new bare-metal host to be used.
${BMC_ADDRESS} — The URL for the bare-metal host BMC (for example, redfish-virtualmedia://192.168.200.75/redfish/v1/Systems/1/). To learn more about the different options available depending on your hardware provider, check the following link.

Note

Architecture must be either x86_64 or aarch64, depending on the architecture of the bare-metal host to be enrolled.
If no network configuration for the host has been specified, either at image build time or through the BareMetalHost definition, an autoconfiguration mechanism (DHCP, DHCPv6, SLAAC) will be used. For more details or complex configurations, check the Chapter 53, Advanced Network Configuration.

Once the file is created, the following command has to be executed in the management cluster to start enrolling the new bare-metal host in the management cluster:

$ kubectl apply -f bmh-example.yaml

The new bare-metal host object will be enrolled, changing its state from registering to inspecting and available. The changes can be checked using the following command:

$ kubectl get bmh

Note

The BaremetalHost object is in the registering state until the BMC credentials are validated. Once the credentials are validated, the BaremetalHost object changes its state to inspecting, and this step could take some time depending on the hardware (up to 20 minutes). During the inspecting phase, the hardware information is retrieved and the Kubernetes object is updated. Check the information using the following command: kubectl get bmh -o yaml.

Provision step

Once the bare-metal host is enrolled and available, the next step is to provision the bare-metal host to install and configure the operating system and the Kubernetes cluster. To do that, the following file (capi-provisioning-example.yaml) has to be created in the management-cluster with the following information (the capi-provisioning-example.yaml can be generated by joining the following blocks).

Note

Only values between $\{…\} must be replaced with the real values.

The following block is the cluster definition, where the networking can be configured using the pods and the services blocks. Also, it contains the references to the control plane and the infrastructure (using the Metal³ provider) objects to be used.

apiVersion: cluster.x-k8s.io/v1beta2
kind: Cluster
metadata:
  name: single-node-cluster
  namespace: default
  labels:
    cluster-api.cattle.io/rancher-auto-import: "true"
spec:
  clusterNetwork:
    pods:
      cidrBlocks:
        - 192.168.0.0/18
        - fd00:bad:cafe::/48
    services:
      cidrBlocks:
        - 10.96.0.0/12
        - fd00:bad:bad:cafe::/112
  controlPlaneRef:
    apiVersion: controlplane.cluster.x-k8s.io/v1beta2
    kind: RKE2ControlPlane
    name: single-node-cluster
  infrastructureRef:
    apiVersion: infrastructure.cluster.x-k8s.io/v1beta2
    kind: Metal3Cluster
    name: single-node-cluster

Note

Both single-stack and dual-stack deployments are possible, remove the IPv6 CIDRs from the above definition for an IPv4 only cluster.
Single-stack IPv6 deployments are in tech preview status and not yet officially supported.
Adding the label cluster-api.cattle.io/rancher-auto-import: "true" to the cluster.x-k8s.io objects will import the cluster into Rancher (by creating a corresponding clusters.management.cattle.io object). See the Cluster API documentation for more information.

The Metal3Cluster object specifies the control-plane endpoint (replacing the ${DOWNSTREAM_CONTROL_PLANE_IPV4}) to be configured and the noCloudProvider because a bare-metal node is used.

apiVersion: infrastructure.cluster.x-k8s.io/v1beta2
kind: Metal3Cluster
metadata:
  name: single-node-cluster
  namespace: default
spec:
  controlPlaneEndpoint:
    host: ${DOWNSTREAM_CONTROL_PLANE_IPV4}
    port: 6443
  noCloudProvider: true

The RKE2ControlPlane object specifies the control-plane configuration to be used and the Metal3MachineTemplate object specifies the control-plane image to be used. Also, it contains the information about the number of replicas to be used (in this case, one) and the CNI plug-in to be used (in this case, Cilium). The agentConfig block contains the Ignition format to be used and the additionalUserData to be used to configure the RKE2 node with information like a systemd named rke2-preinstall.service to replace automatically the BAREMETALHOST_UUID and node-name during the provisioning process using the Ironic information. To enable multus with cilium a file is created in the rke2 server manifests directory named rke2-cilium-config.yaml with the configuration to be used. The last block of information contains the Kubernetes version to be used. ${RKE2_VERSION} is the version of RKE2 to be used replacing this value (for example, v1.35.3+rke2r3).

apiVersion: controlplane.cluster.x-k8s.io/v1beta2
kind: RKE2ControlPlane
metadata:
  name: single-node-cluster
  namespace: default
  annotations: {
    rke2.controlplane.cluster.x-k8s.io/load-balancer-exclusion: "true"
  }
spec:
  machineTemplate:
  infrastructureRef:
    apiVersion: infrastructure.cluster.x-k8s.io/v1beta2
    kind: Metal3MachineTemplate
    name: single-node-cluster-controlplane
  replicas: 1
  version: ${RKE2_VERSION}
  rolloutStrategy:
    type: "RollingUpdate"
    rollingUpdate:
      maxSurge: 0
  serverConfig:
    cni: cilium
  agentConfig:
    format: ignition
    additionalUserData:
      config: |
        variant: fcos
        version: 1.4.0
        systemd:
          units:
          - name: rke2-preinstall.service
            enabled: true
            contents: |
              [Unit]
              Description=rke2-preinstall
              Wants=network-online.target
              Before=rke2-install.service
              ConditionPathExists=!/run/cluster-api/bootstrap-success.complete
              [Service]
              Type=oneshot
              User=root
              ExecStartPre=/bin/sh -c "mount -L config-2 /mnt"
              ExecStart=/bin/sh -c "sed -i \"s/BAREMETALHOST_UUID/$(jq -r .uuid /mnt/openstack/latest/meta_data.json)/\" /etc/rancher/rke2/config.yaml"
              ExecStart=/bin/sh -c "echo \"node-name: $(jq -r .name /mnt/openstack/latest/meta_data.json)\" >> /etc/rancher/rke2/config.yaml"
              ExecStart=/bin/sh -c "echo \"node-label:\" >> /etc/rancher/rke2/config.yaml"
              ExecStart=/bin/sh -c "echo \"  - metal3.io/uuid=$(jq -r .uuid /mnt/openstack/latest/meta_data.json)\" >> /etc/rancher/rke2/config.yaml"
              ExecStartPost=/bin/sh -c "umount /mnt"
              [Install]
              WantedBy=multi-user.target
          # rke2-traefik-deployment.service unit to be removed once "traefik" being the default ingress controller (starting with RKE2 v1.36)
          - name: rke2-traefik-deployment.service
            enabled: true
            contents: |
              [Unit]
              Description=rke2-traefik-deployment
              Wants=rke2-preinstall.service
              Before=rke2-install.service
              ConditionPathExists=!/run/cluster-api/bootstrap-success.complete
              [Service]
              Type=oneshot
              User=root
              ExecStart=/bin/sh -c "echo \"ingress-controller: traefik\" >> /etc/rancher/rke2/config.yaml"
              [Install]
              WantedBy=multi-user.target
        storage:
          directories:
          - path: /var/lib/rancher/rke2/server/manifests
            overwrite: true
          files:
          # https://docs.rke2.io/networking/multus_sriov#using-multus-with-cilium
          - path: /var/lib/rancher/rke2/server/manifests/rke2-cilium-config.yaml
            overwrite: true
            contents:
              inline: |
                apiVersion: helm.cattle.io/v1
                kind: HelmChartConfig
                metadata:
                  name: rke2-cilium
                  namespace: kube-system
                spec:
                  valuesContent: |-
                    cni:
                      exclusive: false
            mode: 0644
            user:
              name: root
            group:
              name: root
          - path: /var/lib/rancher/rke2/server/manifests/rke2-traefik-config.yaml
            overwrite: true
            contents:
              inline: |
                apiVersion: helm.cattle.io/v1
                kind: HelmChartConfig
                metadata:
                  name: rke2-traefik
                  namespace: kube-system
                spec:
                  valuesContent: |-
                    ingressClass:
                      isDefaultClass: true
                    ports:
                      web:
                        hostPort: null    # disallow hostPort
                        exposedPort: 80
                      websecure:
                        hostPort: null    # disallow hostPort
                        exposedPort: 443
                    service:
                      enabled: true
                      type: LoadBalancer
                      spec:
                        externalTrafficPolicy: Local
                        allocateLoadBalancerNodePorts: false  # k8s GA from 1.24; supported by MetalLB
            mode: 0644
            user:
              name: root
            group:
              name: root
    kubelet:
      extraArgs:
      - provider-id=metal3://BAREMETALHOST_UUID
    nodeName: "localhost.localdomain"

The Metal3MachineTemplate object specifies the following information:

The dataTemplate to be used as a reference to the template.
The hostSelector to be used matching with the label created during the enrollment process.
The image to be used as a reference to the image generated using EIB on the previous section (Chapter 49, Prepare downstream cluster image for connected scenarios), and the checksum and checksumType to be used to validate the image.

apiVersion: infrastructure.cluster.x-k8s.io/v1beta2
kind: Metal3MachineTemplate
metadata:
  name: single-node-cluster-controlplane
  namespace: default
spec:
  template:
    spec:
      dataTemplate:
        name: single-node-cluster-controlplane-template
      hostSelector:
        matchLabels:
          cluster-role: control-plane
      image:
        checksum: http://imagecache.local:8080/eibimage-output-telco.raw.sha256
        checksumType: sha256
        format: raw
        url: http://imagecache.local:8080/eibimage-output-telco.raw

The Metal3DataTemplate object specifies the metaData for the downstream cluster.

apiVersion: infrastructure.cluster.x-k8s.io/v1beta2
kind: Metal3DataTemplate
metadata:
  name: single-node-cluster-controlplane-template
  namespace: default
spec:
  clusterName: single-node-cluster
  metaData:
    objectNames:
      - key: name
        object: machine
      - key: local-hostname
        object: machine
      - key: local_hostname
        object: machine

Once the file is created by joining the previous blocks, the following command must be executed in the management cluster to start provisioning the new bare-metal host:

$ kubectl apply -f capi-provisioning-example.yaml