Azure Quickstart Part 2

This guide walks you through building and accessing a custom API with Crossplane.

Prerequisites

• Complete quickstart part 1 connecting Kubernetes to Azure.
• an Azure account with permissions to create an Azure Virtual Machine, Resource Group and Virtual Networking.

1helm repo add \
2crossplane-stable https://charts.crossplane.io/stable
3helm repo update
4&&
5helm install crossplane \
6crossplane-stable/crossplane \
7--namespace crossplane-system \
8--create-namespace

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apiVersion: pkg.crossplane.io/v1
kind: Provider
metadata:
  name: provider-azure-network
spec:
  package: xpkg.crossplane.io/crossplane-contrib/provider-azure-network:v1.11.2

1kubectl apply -f https://deploy-preview-1086--crossplane.netlify.app/v1.20/manifests/getting-started/azure-part-2/provider-azure-network.yaml

1az ad sp create-for-rbac \
2--sdk-auth \
3--role Owner \
4--scopes /subscriptions/

1kubectl create secret \
2generic azure-secret \
3-n crossplane-system \
4--from-file=creds=./azure-credentials.json

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apiVersion: azure.upbound.io/v1beta1
metadata:
  name: default
kind: ProviderConfig
spec:
  credentials:
    source: Secret
    secretRef:
      namespace: crossplane-system
      name: azure-secret
      key: creds

1kubectl apply -f https://deploy-preview-1086--crossplane.netlify.app/v1.20/manifests/getting-started/azure-part-2/providerconfig.yaml

Create a custom API

Crossplane allows you to build your own custom APIs for your users, abstracting away details about the cloud provider and their resources. You can make your API as complex or simple as you wish.

The custom API is a Kubernetes object. Here is an example custom API.

1apiVersion: compute.example.com/v1alpha1
2kind: VirtualMachine
3metadata:
4  name: my-vm
5spec:
6  location: "US"

Like any Kubernetes object the API has a version, kind and spec.

Define a group and version

To create your own API start by defining an API group and version.

The group can be any value, but common convention is to map to a fully qualified domain name.

The version shows how mature or stable the API is and increments when changing, adding or removing fields in the API.

Crossplane doesn’t require specific versions or a specific version naming convention, but following Kubernetes API versioning guidelines is strongly recommended.

• v1alpha1 - A new API that may change at any time.
• v1beta1 - An existing API that’s considered stable. Breaking changes are strongly discouraged.
• v1 - A stable API that doesn’t have breaking changes.

This guide uses the group compute.example.com.

Because this is the first version of the API, this guide uses the version v1alpha1.

1apiVersion: compute.example.com/v1alpha1

Define a kind

The API group is a logical collection of related APIs. In a group are individual kinds representing different resources.

For example a compute group may have a VirtualMachine and BareMetal kinds.

The kind can be anything, but it must be UpperCamelCased.

This API’s kind is VirtualMachine

1apiVersion: compute.example.com/v1alpha1
2kind: VirtualMachine

Define a spec

The most important part of an API is the schema. The schema defines the inputs accepted from users.

This API allows users to provide a location of where to run their cloud resources.

All other resource settings can’t be configurable by the users. This allows Crossplane to enforce any policies and standards without worrying about user errors.

1apiVersion: compute.example.com/v1alpha1
2kind: VirtualMachine
3spec:
4  location: "US"

Apply the API

Crossplane uses Composite Resource Definitions (also called an XRD) to install your custom API in Kubernetes.

The XRD spec contains all the information about the API including the group, version, kind and schema.

The XRD’s name must be the combination of the plural and group.

The schema uses the OpenAPIv3 specification to define the API spec.

The API defines a location that must be oneOf either EU or US.

Apply this XRD to create the custom API in your Kubernetes cluster.

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apiVersion: apiextensions.crossplane.io/v1
kind: CompositeResourceDefinition
metadata:
  name: virtualmachines.compute.example.com
spec:
  group: compute.example.com
  names:
    kind: VirtualMachine
    plural: virtualmachines
  versions:
  - name: v1alpha1
    schema:
      openAPIV3Schema:
        type: object
        properties:
          spec:
            type: object
            properties:
              location:
                type: string
                oneOf:
                  - pattern: '^EU$'
                  - pattern: '^US$'
            required:
              - location
    served: true
    referenceable: true
  claimNames:
    kind: VirtualMachineClaim
    plural: virtualmachineclaims

1kubectl apply -f https://deploy-preview-1086--crossplane.netlify.app/v1.20/manifests/getting-started/azure-part-2/virtualmachines.compute.example.com.yaml

Adding the claimNames allows users to access this API either at the cluster level with the VirtualMachine endpoint or in a namespace with the VirtualMachineClaim endpoint.

The namespace scoped API is a Crossplane Claim.

View the installed XRD with kubectl get xrd.

1kubectl get xrd
2NAME                                  ESTABLISHED   OFFERED   AGE
3virtualmachines.compute.example.com   True          True      43s

View the new custom API endpoints with kubectl api-resources | grep VirtualMachine

1kubectl api-resources | grep VirtualMachine
2virtualmachineclaims              compute.example.com/v1alpha1           true         VirtualMachineClaim
3virtualmachines                   compute.example.com/v1alpha1           false        VirtualMachine

Create a deployment template

When users access the custom API Crossplane takes their inputs and combines them with a template describing what infrastructure to deploy. Crossplane calls this template a Composition.

The Composition defines all the cloud resources to deploy. Each entry in the template is a full resource definitions, defining all the resource settings and metadata like labels and annotations.

This template creates an Azure LinuxVirtualMachine NetworkInterface, Subnet VirtualNetwork and ResourceGroup.

This Composition takes the user’s location input and uses it as the location used in the individual resource.

Apply this Composition to your cluster.

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apiVersion: apiextensions.crossplane.io/v1
kind: Composition
metadata:
  name: crossplane-quickstart-vm-with-network
spec:
  mode: Pipeline
  pipeline:
  - step: patch-and-transform
    functionRef:
      name: function-patch-and-transform
    input:
      apiVersion: pt.fn.crossplane.io/v1beta1
      kind: Resources
      resources:
        - name: quickstart-vm
          base:
            apiVersion: compute.azure.upbound.io/v1beta1
            kind: LinuxVirtualMachine
            spec:
              forProvider:
                adminUsername: adminuser
                adminSshKey:
                  - publicKey: ssh-rsa
                      AAAAB3NzaC1yc2EAAAADAQABAAABAQC+wWK73dCr+jgQOAxNsHAnNNNMEMWOHYEccp6wJm2gotpr9katuF/ZAdou5AaW1C61slRkHRkpRRX9FA9CYBiitZgvCCz+3nWNN7l/Up54Zps/pHWGZLHNJZRYyAB6j5yVLMVHIHriY49d/GZTZVNB8GoJv9Gakwc/fuEZYYl4YDFiGMBP///TzlI4jhiJzjKnEvqPFki5p2ZRJqcbCiF4pJrxUQR/RXqVFQdbRLZgYfJ8xGB878RENq3yQ39d8dVOkq4edbkzwcUmwwwkYVPIoDGsYLaRHnG+To7FvMeyO7xDVQkMKzopTQV8AuKpyvpqu0a9pWOMaiCyDytO7GGN
                      example@docs.crossplane.io
                    username: adminuser
                location: "Central US"
                osDisk:
                  - caching: ReadWrite
                    storageAccountType: Standard_LRS
                resourceGroupNameSelector:
                  matchControllerRef: true
                size: Standard_B1ms
                sourceImageReference:
                  - offer: debian-11
                    publisher: Debian
                    sku: 11-backports-gen2
                    version: latest
                networkInterfaceIdsSelector:
                  matchControllerRef: true
          patches:
            - type: FromCompositeFieldPath
              fromFieldPath: "spec.location"
              toFieldPath: "spec.forProvider.location"
              transforms:
                - type: map
                  map:
                    EU: "Sweden Central"
                    US: "Central US"
        - name: quickstart-nic
          base:
            apiVersion: network.azure.upbound.io/v1beta1
            kind: NetworkInterface
            spec:
              forProvider:
                ipConfiguration:
                  - name: crossplane-quickstart-configuration
                    privateIpAddressAllocation: Dynamic
                    subnetIdSelector:
                      matchControllerRef: true
                location: "Central US"
                resourceGroupNameSelector:
                  matchControllerRef: true
          patches:
            - type: FromCompositeFieldPath
              fromFieldPath: "spec.location"
              toFieldPath: "spec.forProvider.location"
              transforms:
                - type: map
                  map:
                    EU: "Sweden Central"
                    US: "Central US"
        - name: quickstart-subnet
          base:
            apiVersion: network.azure.upbound.io/v1beta1
            kind: Subnet
            spec:
              forProvider:
                addressPrefixes:
                  - 10.0.1.0/24
                virtualNetworkNameSelector:
                  matchControllerRef: true
                resourceGroupNameSelector:
                  matchControllerRef: true
        - name: quickstart-network
          base:
            apiVersion: network.azure.upbound.io/v1beta1
            kind: VirtualNetwork
            spec:
              forProvider:
                addressSpace:
                  - 10.0.0.0/16
                location: "Central US"
                resourceGroupNameSelector:
                  matchControllerRef: true
          patches:
            - type: FromCompositeFieldPath
              fromFieldPath: "spec.location"
              toFieldPath: "spec.forProvider.location"
              transforms:
                - type: map
                  map:
                    EU: "Sweden Central"
                    US: "Central US"
        - name: crossplane-resourcegroup
          base:
            apiVersion: azure.upbound.io/v1beta1
            kind: ResourceGroup
            spec:
              forProvider:
                location: Central US
          patches:
            - type: FromCompositeFieldPath
              fromFieldPath: "spec.location"
              toFieldPath: "spec.forProvider.location"
              transforms:
                - type: map
                  map:
                    EU: "Sweden Central"
                    US: "Central US"
  compositeTypeRef:
    apiVersion: compute.example.com/v1alpha1
    kind: VirtualMachine

1kubectl apply -f https://deploy-preview-1086--crossplane.netlify.app/v1.20/manifests/getting-started/azure-part-2/crossplane-quickstart-vm-with-network.yaml

The compositeTypeRef defines which custom APIs can use this template to create resources.

A Composition uses a pipeline of composition functions to define the cloud resources to deploy. This template uses function-patch-and-transform. You must install the function before you can use it in a Composition.

Apply this Function to install function-patch-and-transform:

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apiVersion: pkg.crossplane.io/v1
kind: Function
metadata:
  name: function-patch-and-transform
spec:
  package: xpkg.crossplane.io/crossplane-contrib/function-patch-and-transform:v0.8.2

1kubectl apply -f https://deploy-preview-1086--crossplane.netlify.app/v1.20/manifests/getting-started/azure-part-2/function-patch-and-transform.yaml

View the Composition with kubectl get composition

1kubectl get composition
2NAME                                    XR-KIND           XR-APIVERSION                     AGE
3crossplane-quickstart-vm-with-network   XVirtualMachine   custom-api.example.org/v1alpha1   77s

Install the Azure virtual machine provider

Part 1 only installed the Azure Virtual Network Provider. To deploying virtual machines requires the Azure Compute provider as well.

Add the new Provider to the cluster.

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apiVersion: pkg.crossplane.io/v1
kind: Provider
metadata:
  name: provider-azure-compute
spec:
  package: xpkg.crossplane.io/crossplane-contrib/provider-azure-compute:v1.11.2

1kubectl apply -f https://deploy-preview-1086--crossplane.netlify.app/v1.20/manifests/getting-started/azure-part-2/provider-azure-compute.yaml

View the new Compute provider with kubectl get providers.

1kubectl get providers
2NAME                                       INSTALLED   HEALTHY   PACKAGE                                                                AGE
3crossplane-contrib-provider-family-azure   True        True      xpkg.crossplane.io/crossplane-contrib/provider-family-azure:v1.11.2    23m
4provider-azure-compute                     True        True      xpkg.crossplane.io/crossplane-contrib/provider-azure-compute:v1.11.2   2m54s
5provider-azure-network                     True        True      xpkg.crossplane.io/crossplane-contrib/provider-azure-network:v1.11.2   23m

Access the custom API

With the custom API (XRD) installed and associated to a resource template (Composition) users can access the API to create resources.

Create a VirtualMachine object to create the cloud resources.

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apiVersion: compute.example.com/v1alpha1
kind: VirtualMachine
metadata:
  name: my-vm
spec:
  location: "EU"

1kubectl apply -f https://deploy-preview-1086--crossplane.netlify.app/v1.20/manifests/getting-started/azure-part-2/virtualmachine-my-vm.yaml

View the resource with kubectl get VirtualMachine.

1kubectl get VirtualMachine
2NAME    SYNCED   READY   COMPOSITION                             AGE
3my-vm   True     True    crossplane-quickstart-vm-with-network   3m3s

This object is a Crossplane composite resource (also called an XR). It’s a single object representing the collection of resources created from the Composition template.

View the individual resources with kubectl get managed

 1kubectl get managed
 2NAME                                         READY   SYNCED   EXTERNAL-NAME   AGE
 3resourcegroup.azure.upbound.io/my-vm-7jb4n   True    True     my-vm-7jb4n     3m43s
 4
 5NAME                                                       READY   SYNCED   EXTERNAL-NAME   AGE
 6linuxvirtualmachine.compute.azure.upbound.io/my-vm-5h7p4   True    True     my-vm-5h7p4     3m43s
 7
 8NAME                                                    READY   SYNCED   EXTERNAL-NAME   AGE
 9networkinterface.network.azure.upbound.io/my-vm-j7fpx   True    True     my-vm-j7fpx     3m43s
10
11NAME                                          READY   SYNCED   EXTERNAL-NAME   AGE
12subnet.network.azure.upbound.io/my-vm-b2dqt   True    True     my-vm-b2dqt     3m43s
13
14NAME                                                  READY   SYNCED   EXTERNAL-NAME   AGE
15virtualnetwork.network.azure.upbound.io/my-vm-pd2sw   True    True     my-vm-pd2sw     3m43s

Accessing the API created all five resources defined in the template and linked them together.

Look at a specific resource to see it’s created in the location used in the API.

1kubectl describe linuxvirtualmachine | grep Location
2    Location:                         Sweden Central
3    Location:                         swedencentral

Delete the resources with kubectl delete VirtualMachine.

1kubectl delete VirtualMachine my-vm
2virtualmachine.compute.example.com "my-vm" deleted

Verify Crossplane deleted the resources with kubectl get managed

1kubectl get managed
2No resources found

Using the API with namespaces

Accessing the API VirtualMachine happens at the cluster scope. Most organizations isolate their users into namespaces.

A Crossplane Claim is the custom API in a namespace.

Creating a Claim is just like accessing the custom API endpoint, but with the kind from the custom API’s claimNames.

Create a new namespace to test create a Claim in.

1kubectl create namespace crossplane-test

Then create a Claim in the crossplane-test namespace.

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apiVersion: compute.example.com/v1alpha1
kind: VirtualMachineClaim
metadata:
  name: my-namespaced-vm
  namespace: crossplane-test
spec:
  location: "EU"

1kubectl apply -f https://deploy-preview-1086--crossplane.netlify.app/v1.20/manifests/getting-started/azure-part-2/virtualmachineclaim-my-namespaced-vm.yaml

1kubectl get claim -n crossplane-test
2NAME               SYNCED   READY   CONNECTION-SECRET   AGE
3my-namespaced-vm   True     True                        5m11s

The Claim automatically creates a composite resource, which creates the managed resources.

View the Crossplane created composite resource with kubectl get composite.

1kubectl get composite
2NAME                     SYNCED   READY   COMPOSITION                             AGE
3my-namespaced-vm-r7gdr   True     True    crossplane-quickstart-vm-with-network   5m33s

Again, view the managed resources with kubectl get managed.

 1NAME                                                          READY   SYNCED   EXTERNAL-NAME                  AGE
 2resourcegroup.azure.upbound.io/my-namespaced-vm-r7gdr-cvzw6   True    True     my-namespaced-vm-r7gdr-cvzw6   5m51s
 3
 4NAME                                                                        READY   SYNCED   EXTERNAL-NAME                  AGE
 5linuxvirtualmachine.compute.azure.upbound.io/my-namespaced-vm-r7gdr-vrbgb   True    True     my-namespaced-vm-r7gdr-vrbgb   5m51s
 6
 7NAME                                                                     READY   SYNCED   EXTERNAL-NAME                  AGE
 8networkinterface.network.azure.upbound.io/my-namespaced-vm-r7gdr-hwrb8   True    True     my-namespaced-vm-r7gdr-hwrb8   5m51s
 9
10NAME                                                           READY   SYNCED   EXTERNAL-NAME                  AGE
11subnet.network.azure.upbound.io/my-namespaced-vm-r7gdr-gh468   True    True     my-namespaced-vm-r7gdr-gh468   5m51s
12
13NAME                                                                   READY   SYNCED   EXTERNAL-NAME                  AGE
14virtualnetwork.network.azure.upbound.io/my-namespaced-vm-r7gdr-5qhz7   True    True     my-namespaced-vm-r7gdr-5qhz7   5m51s

Deleting the Claim deletes all the Crossplane generated resources.

kubectl delete claim -n crossplane-test my-VirtualMachine-database

1kubectl delete claim -n crossplane-test my-namespaced-vm
2virtualmachineclaim.compute.example.com "my-namespaced-vm" deleted

Verify Crossplane deleted the composite resource with kubectl get composite.

1kubectl get composite
2No resources found

Verify Crossplane deleted the managed resources with kubectl get managed.

1kubectl get managed
2No resources found

Next steps

• Explore Azure resources that Crossplane can configure in the Provider CRD reference.
• Join the Crossplane Slack and connect with Crossplane users and contributors.
• Read more about the Crossplane concepts to find out what else you can do with Crossplane.