Azure Quickstart Part 2

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Important

This guide is part 2 of a series.

Part 1 covers to installing Crossplane and connect your Kubernetes cluster to Azure.

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.

Add the Crossplane Helm repository and install Crossplane

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

When the Crossplane pods finish installing and are ready, apply the Azure Provider

1cat <<EOF | kubectl apply -f -
2apiVersion: pkg.crossplane.io/v1
3kind: Provider
4metadata:
5  name: provider-azure-network
6spec:
7  package: xpkg.upbound.io/upbound/provider-azure-network:v0.42.1
8EOF

Use the Azure CLI to create a service principal and save the JSON output as azure-crednetials.json

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

Create a Kubernetes secret from the Azure JSON file.

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

Create a ProviderConfig

 1cat <<EOF | kubectl apply -f -
 2apiVersion: azure.upbound.io/v1beta1
 3metadata:
 4  name: default
 5kind: ProviderConfig
 6spec:
 7  credentials:
 8    source: Secret
 9    secretRef:
10      namespace: crossplane-system
11      name: azure-secret
12      key: creds
13EOF

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.

 1cat <<EOF | kubectl apply -f -
 2apiVersion: apiextensions.crossplane.io/v1
 3kind: CompositeResourceDefinition
 4metadata:
 5  name: virtualmachines.compute.example.com
 6spec:
 7  group: compute.example.com
 8  names:
 9    kind: VirtualMachine
10    plural: virtualmachines
11  versions:
12  - name: v1alpha1
13    schema:
14      openAPIV3Schema:
15        type: object
16        properties:
17          spec:
18            type: object
19            properties:
20              location:
21                type: string
22                oneOf:
23                  - pattern: '^EU$'
24                  - pattern: '^US$'
25            required:
26              - location
27    served: true
28    referenceable: true
29  claimNames:
30    kind: VirtualMachineClaim
31    plural: virtualmachineclaims
32EOF

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.

Tip

For more details on the fields and options of Composite Resource Definitions read the XRD documentation.

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.

Important

This Composition uses an array of resource templates. You can patch each template with data copied from the custom API. Crossplane calls this a Patch and Transform Composition.

You don’t have to use Patch and Transform. Crossplane supports a variety of alternatives, including Go Templating and CUE. You can also write a function in Go or Python to template your resources.

Read the Composition documentation for more information on configuring Compositions and all the available options.

Apply this Composition to your cluster.

  1cat <<EOF | kubectl apply -f -
  2apiVersion: apiextensions.crossplane.io/v1
  3kind: Composition
  4metadata:
  5  name: crossplane-quickstart-vm-with-network
  6spec:
  7  mode: Pipeline
  8  pipeline:
  9  - step: patch-and-transform
 10    functionRef:
 11      name: function-patch-and-transform
 12    input:
 13      apiVersion: pt.fn.crossplane.io/v1beta1
 14      kind: Resources
 15      resources:
 16        - name: quickstart-vm
 17          base:
 18            apiVersion: compute.azure.upbound.io/v1beta1
 19            kind: LinuxVirtualMachine
 20            spec:
 21              forProvider:
 22                adminUsername: adminuser
 23                adminSshKey:
 24                  - publicKey: ssh-rsa
 25                      AAAAB3NzaC1yc2EAAAADAQABAAABAQC+wWK73dCr+jgQOAxNsHAnNNNMEMWOHYEccp6wJm2gotpr9katuF/ZAdou5AaW1C61slRkHRkpRRX9FA9CYBiitZgvCCz+3nWNN7l/Up54Zps/pHWGZLHNJZRYyAB6j5yVLMVHIHriY49d/GZTZVNB8GoJv9Gakwc/fuEZYYl4YDFiGMBP///TzlI4jhiJzjKnEvqPFki5p2ZRJqcbCiF4pJrxUQR/RXqVFQdbRLZgYfJ8xGB878RENq3yQ39d8dVOkq4edbkzwcUmwwwkYVPIoDGsYLaRHnG+To7FvMeyO7xDVQkMKzopTQV8AuKpyvpqu0a9pWOMaiCyDytO7GGN
 26                      example@docs.crossplane.io
 27                    username: adminuser
 28                location: "Central US"
 29                osDisk:
 30                  - caching: ReadWrite
 31                    storageAccountType: Standard_LRS
 32                resourceGroupNameSelector:
 33                  matchControllerRef: true
 34                size: Standard_B1ms
 35                sourceImageReference:
 36                  - offer: debian-11
 37                    publisher: Debian
 38                    sku: 11-backports-gen2
 39                    version: latest
 40                networkInterfaceIdsSelector:
 41                  matchControllerRef: true
 42          patches:
 43            - type: FromCompositeFieldPath
 44              fromFieldPath: "spec.location"
 45              toFieldPath: "spec.forProvider.location"
 46              transforms:
 47                - type: map
 48                  map: 
 49                    EU: "Sweden Central"
 50                    US: "Central US"
 51        - name: quickstart-nic
 52          base:
 53            apiVersion: network.azure.upbound.io/v1beta1
 54            kind: NetworkInterface
 55            spec:
 56              forProvider:
 57                ipConfiguration:
 58                  - name: crossplane-quickstart-configuration
 59                    privateIpAddressAllocation: Dynamic
 60                    subnetIdSelector:
 61                      matchControllerRef: true
 62                location: "Central US"
 63                resourceGroupNameSelector:
 64                  matchControllerRef: true
 65          patches:
 66            - type: FromCompositeFieldPath
 67              fromFieldPath: "spec.location"
 68              toFieldPath: "spec.forProvider.location"
 69              transforms:
 70                - type: map
 71                  map: 
 72                    EU: "Sweden Central"
 73                    US: "Central US"            
 74        - name: quickstart-subnet
 75          base:
 76            apiVersion: network.azure.upbound.io/v1beta1
 77            kind: Subnet
 78            spec:
 79              forProvider:
 80                addressPrefixes:
 81                  - 10.0.1.0/24
 82                virtualNetworkNameSelector:
 83                  matchControllerRef: true
 84                resourceGroupNameSelector:
 85                  matchControllerRef: true
 86        - name: quickstart-network
 87          base:
 88            apiVersion: network.azure.upbound.io/v1beta1
 89            kind: VirtualNetwork
 90            spec:
 91              forProvider:
 92                addressSpace:
 93                  - 10.0.0.0/16
 94                location: "Central US"
 95                resourceGroupNameSelector:
 96                  matchControllerRef: true
 97          patches:
 98            - type: FromCompositeFieldPath
 99              fromFieldPath: "spec.location"
100              toFieldPath: "spec.forProvider.location"
101              transforms:
102                - type: map
103                  map: 
104                    EU: "Sweden Central"
105                    US: "Central US"
106        - name: crossplane-resourcegroup
107          base:
108            apiVersion: azure.upbound.io/v1beta1
109            kind: ResourceGroup
110            spec:
111              forProvider:
112                location: Central US
113          patches:
114            - type: FromCompositeFieldPath
115              fromFieldPath: "spec.location"
116              toFieldPath: "spec.forProvider.location"
117              transforms:
118                - type: map
119                  map: 
120                    EU: "Sweden Central"
121                    US: "Central US"
122  compositeTypeRef:
123    apiVersion: compute.example.com/v1alpha1
124    kind: VirtualMachine
125EOF

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:

1cat <<EOF | kubectl apply -f -
2apiVersion: pkg.crossplane.io/v1
3kind: Function
4metadata:
5  name: function-patch-and-transform
6spec:
7  package: xpkg.upbound.io/crossplane-contrib/function-patch-and-transform:v0.1.4
8EOF

Tip

Read the Composition documentation for more information on configuring Compositions and all the available options.

Read the Patch and Transform function documentation for more information on how it uses patches to map user inputs to Composition resource templates.

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.

1cat <<EOF | kubectl apply -f -
2apiVersion: pkg.crossplane.io/v1
3kind: Provider
4metadata:
5  name: provider-azure-compute
6spec:
7  package: xpkg.upbound.io/upbound/provider-azure-compute:v0.42.1
8EOF

View the new Compute provider with kubectl get providers.

1kubectl get providers
2NAME                            INSTALLED   HEALTHY   PACKAGE                                                  AGE
3provider-azure-compute          True        True      xpkg.upbound.io/upbound/provider-azure-compute:v0.42.1   25s
4provider-azure-network          True        True      xpkg.upbound.io/upbound/provider-azure-network:v0.42.1   3h
5upbound-provider-family-azure   True        True      xpkg.upbound.io/upbound/provider-family-azure:v0.42.1    3h

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.

1cat <<EOF | kubectl apply -f -
2apiVersion: compute.example.com/v1alpha1
3kind: VirtualMachine
4metadata:
5  name: my-vm
6spec: 
7  location: "EU"
8EOF

View the resource with kubectl get VirtualMachine.

Note

It may take up to five minutes for the resources to provision.

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

Note

It may take up to 5 minutes to delete the resources.

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.

1cat <<EOF | kubectl apply -f -
2apiVersion: compute.example.com/v1alpha1
3kind: VirtualMachineClaim
4metadata:
5  name: my-namespaced-vm
6  namespace: crossplane-test
7spec: 
8  location: "EU"
9EOF

View the Claim with kubectl get claim -n crossplane-test.

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

Note

It may take up to 5 minutes to delete the resources.

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.

Azure Quickstart Part 2

Prerequisites

Skip part 1 and just get started

Create a custom API

Define a group and version

Define a kind

Define a spec

Apply the API

Create a deployment template

Install the Azure virtual machine provider

Access the custom API

Using the API with namespaces

Next steps