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provider-aws-part-2.md

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AWS Quickstart Part 2
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{{< hint "important" >}} This guide is part 2 of a series.

[Part 1]({{<ref "provider-aws" >}}) covers to installing Crossplane and connect your Kubernetes cluster to AWS.

{{< /hint >}}

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

Prerequisites

  • Complete [quickstart part 1]({{<ref "provider-aws" >}}) connecting Kubernetes to AWS.
  • an AWS account with permissions to create an AWS S3 storage bucket and a DynamoDB instance

{{<expand "Skip part 1 and just get started" >}}

  1. Add the Crossplane Helm repository and install Crossplane
helm repo add \
crossplane-stable https://charts.crossplane.io/stable
helm repo update

helm install crossplane \
crossplane-stable/crossplane \
--namespace crossplane-system \
--create-namespace
  1. When the Crossplane pods finish installing and are ready, apply the AWS Provider
cat <<EOF | kubectl apply -f -
apiVersion: pkg.crossplane.io/v1
kind: Provider
metadata:
  name: provider-aws-s3
spec:
  package: xpkg.crossplane.io/crossplane-contrib/provider-aws-s3:v1.21.1
EOF
  1. Create a file with your AWS keys
[default]
aws_access_key_id = <aws_access_key>
aws_secret_access_key = <aws_secret_key>
  1. Create a Kubernetes secret from the AWS keys
kubectl create secret \
generic aws-secret \
-n crossplane-system \
--from-file=creds=./aws-credentials.txt
  1. Create a ProviderConfig
cat <<EOF | kubectl apply -f -
apiVersion: aws.upbound.io/v1beta1
kind: ProviderConfig
metadata:
  name: default
spec:
  credentials:
    source: Secret
    secretRef:
      namespace: crossplane-system
      name: aws-secret
      key: creds
EOF

{{}}

Install the DynamoDB Provider

Part 1 only installed the AWS S3 Provider. This section deploys an S3 bucket along with a DynamoDB Table. Deploying a DynamoDB Table requires the DynamoDB Provider as well.

Add the new Provider to the cluster.

cat <<EOF | kubectl apply -f -
apiVersion: pkg.crossplane.io/v1
kind: Provider
metadata:
  name: provider-aws-dynamodb
spec:
  package: xpkg.crossplane.io/crossplane-contrib/provider-aws-dynamodb:v1.21.1
EOF

View the new DynamoDB provider with kubectl get providers.

kubectl get providers
NAME                                     INSTALLED   HEALTHY   PACKAGE                                                               AGE
crossplane-contrib-provider-family-aws   True        True      xpkg.crossplane.io/crossplane-contrib/provider-family-aws:v1.21.1     15m
provider-aws-dynamodb                    True        True      xpkg.crossplane.io/crossplane-contrib/provider-aws-dynamodb:v1.21.1   22s
provider-aws-s3                          True        True      xpkg.crossplane.io/crossplane-contrib/provider-aws-s3:v1.21.1         15m

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.

apiVersion: database.example.com/v1alpha1
kind: NoSQL
metadata:
  name: my-nosql-database
spec:
  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 {{}}database.example.com{{}}.

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

apiVersion: database.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 database group may have a Relational and NoSQL kinds.

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

This API's kind is {{}}NoSQL{{}}

apiVersion: database.example.com/v1alpha1
kind: NoSQL

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.

apiVersion: database.example.com/v1alpha1
kind: NoSQL
spec:
  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.

cat <<EOF | kubectl apply -f -
apiVersion: apiextensions.crossplane.io/v1
kind: CompositeResourceDefinition
metadata:
  name: nosqls.database.example.com
spec:
  group: database.example.com
  names:
    kind: NoSQL
    plural: nosqls
  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: NoSQLClaim
    plural: nosqlclaim
EOF

Adding the {{}}claimNames{{}} allows users to access this API either at the cluster level with the {{}}nosql{{}} endpoint or in a namespace with the {{}}nosqlclaim{{}} endpoint.

The namespace scoped API is a Crossplane Claim.

{{<hint "tip" >}} For more details on the fields and options of Composite Resource Definitions read the [XRD documentation]({{<ref "../concepts/composite-resource-definitions">}}). {{< /hint >}}

View the installed XRD with kubectl get xrd.

kubectl get xrd
NAME                          ESTABLISHED   OFFERED   AGE
nosqls.database.example.com   True          True      2s

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

kubectl api-resources | grep nosql
nosqlclaim                                     database.example.com/v1alpha1          true         NoSQLClaim
nosqls                                         database.example.com/v1alpha1          false        NoSQL

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 definition, defining all the resource settings and metadata like labels and annotations.

This template creates an AWS {{}}S3{{}} {{}}Bucket{{}} and a {{}}DynamoDB{{}} {{}}Table{{}}.

This Composition takes the user's {{}}location{{}} input and uses it as the {{}}region{{}} used in the individual resource.

{{<hint "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]({{<ref "../concepts/compositions">}}) for more information on configuring Compositions and all the available options. {{< /hint >}}

Apply this Composition to your cluster.

cat <<EOF | kubectl apply -f -
apiVersion: apiextensions.crossplane.io/v1
kind: Composition
metadata:
  name: dynamo-with-bucket
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: s3Bucket
          base:
            apiVersion: s3.aws.upbound.io/v1beta1
            kind: Bucket
            spec:
              forProvider:
                region: us-east-2
              providerConfigRef:
                name: default
          patches:
            - type: FromCompositeFieldPath
              fromFieldPath: "spec.location"
              toFieldPath: "spec.forProvider.region"
              transforms:
                - type: map
                  map:
                    EU: "eu-north-1"
                    US: "us-east-2"
        - name: dynamoDB
          base:
            apiVersion: dynamodb.aws.upbound.io/v1beta1
            kind: Table
            spec:
              forProvider:
                region: "us-east-2"
                writeCapacity: 1
                readCapacity: 1
                attribute:
                  - name: S3ID
                    type: S
                hashKey: S3ID
              providerConfigRef:
                name: default
          patches:
            - type: FromCompositeFieldPath
              fromFieldPath: "spec.location"
              toFieldPath: "spec.forProvider.region"
              transforms:
                - type: map
                  map:
                    EU: "eu-north-1"
                    US: "us-east-2"
  compositeTypeRef:
    apiVersion: database.example.com/v1alpha1
    kind: NoSQL
EOF

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:

cat <<EOF | kubectl apply -f -
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
EOF

{{<hint "tip" >}} Read the [Composition documentation]({{<ref "../concepts/compositions">}}) for more information on configuring Compositions and all the available options.

Read the [Patch and Transform function documentation]({{<ref "../guides/function-patch-and-transform">}}) for more information on how it uses patches to map user inputs to Composition resource templates. {{< /hint >}}

View the Composition with kubectl get composition

kubectl get composition
NAME                 XR-KIND   XR-APIVERSION                   AGE
dynamo-with-bucket   NoSQL     database.example.com/v1alpha1   3s

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 {{}}NoSQL{{}} object to create the cloud resources.

cat <<EOF | kubectl apply -f -
apiVersion: database.example.com/v1alpha1
kind: NoSQL
metadata:
  name: my-nosql-database
spec:
  location: "US"
EOF

View the resource with kubectl get nosql.

kubectl get nosql
NAME                SYNCED   READY   COMPOSITION          AGE
my-nosql-database   True     True    dynamo-with-bucket   14s

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

kubectl get managed
NAME                                                    READY   SYNCED   EXTERNAL-NAME             AGE
table.dynamodb.aws.upbound.io/my-nosql-database-t5wtx   True    True     my-nosql-database-t5wtx   33s

NAME                                               READY   SYNCED   EXTERNAL-NAME             AGE
bucket.s3.aws.upbound.io/my-nosql-database-xtzph   True    True     my-nosql-database-xtzph   33s

Delete the resources with kubectl delete nosql.

kubectl delete nosql my-nosql-database
nosql.database.example.com "my-nosql-database" deleted

Verify Crossplane deleted the resources with kubectl get managed

{{<hint "note" >}} It may take up to 5 minutes to delete the resources. {{< /hint >}}

kubectl get managed
No resources found

Using the API with namespaces

Accessing the API nosql 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.

kubectl create namespace crossplane-test

Then create a Claim in the crossplane-test namespace.

cat <<EOF | kubectl apply -f -
apiVersion: database.example.com/v1alpha1
kind: NoSQLClaim
metadata:
  name: my-nosql-database
  namespace: crossplane-test
spec:
  location: "US"
EOF

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

kubectl get claim -n crossplane-test
NAME                SYNCED   READY   CONNECTION-SECRET   AGE
my-nosql-database   True     True                        17s

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

View the Crossplane created composite resource with kubectl get composite.

kubectl get composite
NAME                      SYNCED   READY   COMPOSITION          AGE
my-nosql-database-t9qrw   True     True    dynamo-with-bucket   77s

Again, view the managed resources with kubectl get managed.

kubectl get managed
NAME                                                          READY   SYNCED   EXTERNAL-NAME                   AGE
table.dynamodb.aws.upbound.io/my-nosql-database-t9qrw-dcpwv   True    True     my-nosql-database-t9qrw-dcpwv   116s

NAME                                                     READY   SYNCED   EXTERNAL-NAME                   AGE
bucket.s3.aws.upbound.io/my-nosql-database-t9qrw-g98lv   True    True     my-nosql-database-t9qrw-g98lv   117s

Deleting the Claim deletes all the Crossplane generated resources.

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

kubectl delete claim -n crossplane-test my-nosql-database
nosqlclaim.database.example.com "my-nosql-database" deleted

{{<hint "note" >}} It may take up to 5 minutes to delete the resources. {{< /hint >}}

Verify Crossplane deleted the composite resource with kubectl get composite.

kubectl get composite
No resources found

Verify Crossplane deleted the managed resources with kubectl get managed.

kubectl get managed
No resources found

Next steps

  • Explore AWS 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]({{<ref "../concepts">}}) to find out what else you can do with Crossplane.