Crossplane configuration

After installing Crossplane, you must configure it for use. The process of configuring Crossplane includes:

Configure RBAC permissions.
Configure Crossplane with a cloud provider.
Configure managed service access.
Set up Resource classes.
Use Auto DevOps configuration options.
Connect to the PostgreSQL instance.

To allow Crossplane to provision cloud services such as PostgreSQL, the cloud provider stack must be configured with a user account. For example:

A service account for GCP.
An IAM user for AWS.

Some important notes:

This guide uses GCP as an example, but the processes for AWS and Azure are similar.
Crossplane requires the Kubernetes cluster to be VPC native with Alias IPs enabled, so the IP addresses of the pods can be routed within the GCP network.

First, declare some environment variables with configuration for use in this guide:

export PROJECT_ID=crossplane-playground # the GCP project where all resources reside.
export NETWORK_NAME=default # the GCP network where your GKE is provisioned.
export REGION=us-central1 # the GCP region where the GKE cluster is provisioned.

Configure RBAC permissions

For GitLab-managed clusters, role-based access control (RBAC) is configured automatically.

For non-GitLab managed clusters, ensure that the service account for the token provided can manage resources in the database.crossplane.io API group:

Save the following YAML as crossplane-database-role.yaml:

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: crossplane-database-role
  labels:
    rbac.authorization.k8s.io/aggregate-to-edit: "true"
rules:
  - apiGroups:
      - database.crossplane.io
    resources:
      - postgresqlinstances
    verbs:
      - get
      - list
      - create
      - update
      - delete
      - patch
      - watch

Apply the cluster role to the cluster:

kubectl apply -f crossplane-database-role.yaml

Configure Crossplane with a cloud provider

See Configure Your Cloud Provider Account to configure the installed cloud provider stack with a user account.

The Secret, and the Provider resource referencing the Secret, must be applied to the gitlab-managed-apps namespace in the guide. Make sure you change that while following the process.

Configure Managed Service Access

Next, configure connectivity between the PostgreSQL database and the GKE cluster by either:

Using Crossplane as demonstrated below.
Directly in the GCP console by configuring private services access.

Run the following command, which creates a network.yaml file, and configures GlobalAddress and connection resources:

cat > network.yaml <<EOF
---
# gitlab-ad-globaladdress defines the IP range that will be allocated
# for cloud services connecting to the instances in the given Network.

apiVersion: compute.gcp.crossplane.io/v1alpha3
kind: GlobalAddress
metadata:
  name: gitlab-ad-globaladdress
spec:
  providerRef:
    name: gcp-provider
  reclaimPolicy: Delete
  name: gitlab-ad-globaladdress
  purpose: VPC_PEERING
  addressType: INTERNAL
  prefixLength: 16
  network: projects/$PROJECT_ID/global/networks/$NETWORK_NAME
---
# gitlab-ad-connection is what allows cloud services to use the allocated
# GlobalAddress for communication. Behind the scenes, it creates a VPC peering
# to the network that those service instances actually live.

apiVersion: servicenetworking.gcp.crossplane.io/v1alpha3
kind: Connection
metadata:
  name: gitlab-ad-connection
spec:
  providerRef:
    name: gcp-provider
  reclaimPolicy: Delete
  parent: services/servicenetworking.googleapis.com
  network: projects/$PROJECT_ID/global/networks/$NETWORK_NAME
  reservedPeeringRangeRefs:
    - name: gitlab-ad-globaladdress
EOF

Apply the settings specified in the file with the following command:
```
kubectl apply -f network.yaml
```

Verify the creation of the network resources, and that both resources are ready and synced.

kubectl describe connection.servicenetworking.gcp.crossplane.io gitlab-ad-connection
kubectl describe globaladdress.compute.gcp.crossplane.io gitlab-ad-globaladdress

Setting up Resource classes

Use resource classes to define a configuration for the required managed service. This example defines the PostgreSQL Resource class:

Run the following command, which define a gcp-postgres-standard.yaml resource class containing a default CloudSQLInstanceClass with labels:

cat > gcp-postgres-standard.yaml <<EOF
apiVersion: database.gcp.crossplane.io/v1beta1
kind: CloudSQLInstanceClass
metadata:
  name: cloudsqlinstancepostgresql-standard
  labels:
    gitlab-ad-demo: "true"
specTemplate:
  writeConnectionSecretsToNamespace: gitlab-managed-apps
  forProvider:
    databaseVersion: POSTGRES_11_7
    region: $REGION
    settings:
      tier: db-custom-1-3840
      dataDiskType: PD_SSD
      dataDiskSizeGb: 10
      ipConfiguration:
        privateNetwork: projects/$PROJECT_ID/global/networks/$NETWORK_NAME
  # this should match the name of the provider created in the above step
  providerRef:
    name: gcp-provider
  reclaimPolicy: Delete
---
apiVersion: database.gcp.crossplane.io/v1beta1
kind: CloudSQLInstanceClass
metadata:
  name: cloudsqlinstancepostgresql-standard-default
  annotations:
    resourceclass.crossplane.io/is-default-class: "true"
specTemplate:
  writeConnectionSecretsToNamespace: gitlab-managed-apps
  forProvider:
    databaseVersion: POSTGRES_11_7
    region: $REGION
    settings:
      tier: db-custom-1-3840
      dataDiskType: PD_SSD
      dataDiskSizeGb: 10
      ipConfiguration:
        privateNetwork: projects/$PROJECT_ID/global/networks/$NETWORK_NAME
  # this should match the name of the provider created in the above step
  providerRef:
    name: gcp-provider
  reclaimPolicy: Delete
EOF

Apply the resource class configuration with the following command:
```
kubectl apply -f gcp-postgres-standard.yaml
```
Verify creation of the Resource class with the following command:
```
kubectl get cloudsqlinstanceclasses
```

The Resource Classes allow you to define classes of service for a managed service. We could create another CloudSQLInstanceClass which requests for a larger or a faster disk. It could also request for a specific version of the database.

Auto DevOps Configuration Options

You can run the Auto DevOps pipeline with either of the following options:

Setting the Environment variables AUTO_DEVOPS_POSTGRES_MANAGED and AUTO_DEVOPS_POSTGRES_MANAGED_CLASS_SELECTOR to provision PostgreSQL using Crossplane.
Overriding values for the Helm chart:
- Set postgres.managed to true, which selects a default resource class. Mark the resource class with the annotation resourceclass.crossplane.io/is-default-class: "true". The CloudSQLInstanceClass cloudsqlinstancepostgresql-standard-default is used to satisfy the claim.
- Set postgres.managed to true with postgres.managedClassSelector providing the resource class to choose, based on labels. In this case, the value of postgres.managedClassSelector.matchLabels.gitlab-ad-demo="true" selects the CloudSQLInstance class cloudsqlinstancepostgresql-standard to satisfy the claim request.

The Auto DevOps pipeline should provision a PostgresqlInstance when it runs successfully.

To verify the PostgreSQL instance was created, run this command. When the STATUS field of the PostgresqlInstance changes to BOUND, it's successfully provisioned:

$ kubectl get postgresqlinstance

NAME            STATUS   CLASS-KIND              CLASS-NAME                            RESOURCE-KIND      RESOURCE-NAME                               AGE
staging-test8   Bound    CloudSQLInstanceClass   cloudsqlinstancepostgresql-standard   CloudSQLInstance   xp-ad-demo-24-staging-staging-test8-jj55c   9m

The endpoint of the PostgreSQL instance, and the user credentials, are present in a secret called app-postgres within the same project namespace. You can verify the secret with the following command:

$ kubectl describe secret app-postgres

Name:         app-postgres
Namespace:    xp-ad-demo-24-staging
Labels:       <none>
Annotations:  crossplane.io/propagate-from-name: 108e460e-06c7-11ea-b907-42010a8000bd
              crossplane.io/propagate-from-namespace: gitlab-managed-apps
              crossplane.io/propagate-from-uid: 10c79605-06c7-11ea-b907-42010a8000bd

Type:  Opaque

Data
====
privateIP:                            8 bytes
publicIP:                             13 bytes
serverCACertificateCert:              1272 bytes
serverCACertificateCertSerialNumber:  1 bytes
serverCACertificateCreateTime:        24 bytes
serverCACertificateExpirationTime:    24 bytes
username:                             8 bytes
endpoint:                             8 bytes
password:                             27 bytes
serverCACertificateCommonName:        98 bytes
serverCACertificateInstance:          41 bytes
serverCACertificateSha1Fingerprint:   40 bytes

Connect to the PostgreSQL instance

Follow this GCP guide if you would like to connect to the newly provisioned PostgreSQL database instance on CloudSQL.