Version: main 🚧

Machine Config Templates

A MachineConfigTemplate is a reusable, cluster-scoped resource that holds a Go template for either a cloud-init (user data) document or a network-data document. A node provider renders the template when it provisions a Machine, so you can define provisioning configuration once and reference it by name from any node type or Machine instead of inlining it on each one. The platform ships with a few predefined templates that you can use as a starting point.

A template defines a cloudInitTemplate, a networkDataTemplate, or both. A node provider renders the matching field when a property references the template; if that field is unset, provisioning fails.

Create a MachineConfigTemplate

A cloud-init template renders into a cloud-config document. The platform appends the vCluster join command and the resolved SSH keys to the rendered output before applying it to the Machine.

apiVersion: management.loft.sh/v1
kind: MachineConfigTemplate
metadata:
  name: ubuntu-cloud-init
spec:
  displayName: "Ubuntu cloud-init"
  cloudInitTemplate: |
    #cloud-config
    hostname: {{ .Values.NodeClaim.Name }}
    users:
      - name: ubuntu
        sudo: ALL=(ALL) NOPASSWD:ALL
        ssh_authorized_keys:
        {{- range .Values.SSHKeys }}
          - {{ . }}
        {{- end }}
    runcmd:
      - echo "Provisioning {{ .Values.NodeClaim.Name }} in project {{ .Values.Project }}"

A network-data template renders into a cloud-init network-config document. The provider supplies the allocated IP and gateway for the Machine as template variables.

apiVersion: management.loft.sh/v1
kind: MachineConfigTemplate
metadata:
  name: static-network
spec:
  displayName: "Static network"
  networkDataTemplate: |
    version: 2
    ethernets:
      enp1s0:
        # AllocatedIP, PrefixLength, and Gateway are supplied during IP allocation.
        addresses:
          - {{ .Values.AllocatedIP }}/{{ .Values.PrefixLength }}
        gateway4: {{ .Values.Gateway }}
        nameservers:
          addresses: [8.8.8.8, 8.8.4.4]

Fields

Field	Description
`spec.displayName`	Human-readable name shown in the UI.
`spec.cloudInitTemplate`	Go template that renders a `cloud-config` document.
`spec.networkDataTemplate`	Go template that renders a cloud-init `network-config` document.
`spec.owner`	Optional user or team that owns this resource.
`spec.access`	Optional access control list.

Template syntax

Templates use Go text/template syntax with the sprig function library. The root object is .Values. The available fields depend on the template kind and the node provider that renders it.

Cloud-init templates

Variable	Description
`.Values.NodeClaim`	The NodeClaim (Machine) being provisioned.
`.Values.Project`	The project the Machine belongs to.
`.Values.Properties`	Merged properties from the NodeProvider, NodeType, NodeEnvironment, and NodeClaim.
`.Values.SSHKeys`	List of SSH public keys (strings) resolved from the `vcluster.com/ssh-keys` property.

The Metal3 provider additionally exposes .Values.BareMetalHost (the selected BareMetalHost), .Values.AllocatedIP, .Values.PrefixLength, and .Values.Gateway.

Network-data templates

Variable	Description
`.Values.NodeClaim`	The NodeClaim (Machine) being provisioned.
`.Values.Project`	The project the Machine belongs to.
`.Values.Properties`	Merged properties from the NodeProvider, NodeType, NodeEnvironment, and NodeClaim.
`.Values.AllocatedIP`	IP allocated for the Machine from the configured network.
`.Values.PrefixLength`	Network prefix length for the allocated IP. Exposed by the KubeVirt and Metal3 providers.
`.Values.Gateway`	Default gateway for the allocated network.

The Metal3 provider additionally exposes .Values.BareMetalHost (the selected BareMetalHost).

Reference a template

Reference a MachineConfigTemplate by name from the properties of a node type (applies to every Machine of that type) or directly on a Machine:

Property	Renders
`vcluster.com/user-data-template-config`	The referenced template's `cloudInitTemplate`.
`vcluster.com/network-data-template-config`	The referenced template's `networkDataTemplate`.

properties:
  vcluster.com/user-data-template-config: ubuntu-cloud-init
  vcluster.com/network-data-template-config: static-network

The referenced template must define the matching field. A template referenced by vcluster.com/user-data-template-config must set cloudInitTemplate, and one referenced by vcluster.com/network-data-template-config must set networkDataTemplate.

Access control

MachineConfigTemplate resources are cluster-scoped. Use the spec.owner and spec.access fields to control who can use or modify them:

apiVersion: management.loft.sh/v1
kind: MachineConfigTemplate
metadata:
  name: ubuntu-cloud-init
spec:
  displayName: "Ubuntu cloud-init"
  cloudInitTemplate: |
    #cloud-config
    hostname: {{ .Values.NodeClaim.Name }}
  owner:
    user: admin
  access:
    - users:
        - "*"
      verbs:
        - get

Create a MachineConfigTemplate​

Fields​

Template syntax​

Cloud-init templates​

Network-data templates​

Reference a template​

Access control​