# Crossplane configuration

Once Crossplane [is installed](applications.md#crossplane), it must be configured for
use.

The process of configuring Crossplane includes:

1. Configuring RBAC permissions.
1. Configuring Crossplane with a cloud provider.
1. Configure managed service access.
1. Setting up Resource classes.
1. Using Auto DevOps configuration options.
1. 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.

Important notes:

- This guide uses GCP as an example. However, the process for AWS and Azure will be
similar.
- Crossplane requires the Kubernetes cluster to be VPC native with Alias IPs enabled so
that the IP address of the pods are routable within the GCP network.

First, we need to declare some environment variables with configuration that will be used throughout this guide:

```shell
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, 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:

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

      ```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
      ```

  1. Apply the cluster role to the cluster:

      ```shell
      kubectl apply -f crossplane-database-role.yaml
      ```

## Configure Crossplane with a cloud provider

See [Configure Your Cloud Provider Account](https://crossplane.io/docs/v0.4/cloud-providers.html)
to configure the installed cloud provider stack with a user account.

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

[Configure Providers](https://crossplane.io/docs/v0.4/cloud-providers.html)

## Configure Managed Service Access

We need to configure connectivity between the PostgreSQL database and the GKE cluster.
This can done by either:

- Using Crossplane as demonstrated below.
- Directly in the GCP console by
[configuring private services access](https://cloud.google.com/vpc/docs/configure-private-services-access).
Create a GlobalAddress and Connection resources:

```shell
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:

```shell
kubectl apply -f network.yaml
```

You can verify creation of the network resources with the following commands.
Verify that the status of both of these resources is ready and is synced.

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

## Setting up Resource classes

Resource classes are a way of defining a configuration for the required managed service. We will define the Postgres Resource class

- Define a gcp-postgres-standard.yaml resourceclass which contains

1. A default CloudSQLInstanceClass.
1. A CloudSQLInstanceClass with labels.

```shell
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_9_6
    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_9_6
    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:

```shell
kubectl apply -f gcp-postgres-standard.yaml
```

Verify creation of the Resource class with the following command:

```shell
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

The Auto DevOps pipeline can be run with the following options:

The Environment variables, `AUTO_DEVOPS_POSTGRES_MANAGED` and `AUTO_DEVOPS_POSTGRES_MANAGED_CLASS_SELECTOR` need to be set to provision PostgreSQL using Crossplane

Alternatively, the following options can be overridden from the values for the Helm chart.

- `postgres.managed` set to true which will select a default resource class.
     The resource class needs to be marked with the annotation
     `resourceclass.crossplane.io/is-default-class: "true"`. The CloudSQLInstanceClass
     `cloudsqlinstancepostgresql-standard-default` will be used to satisfy the claim.

- `postgres.managed` set 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"`
     will select the CloudSQLInstance class `cloudsqlinstancepostgresql-standard`
     to satisfy the claim request.

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

Verify creation of the PostgreSQL Instance.

```shell
kubectl get postgresqlinstance
```

Sample Output: The `STATUS` field of the PostgresqlInstance transitions to `BOUND` when it is successfully provisioned.

```plaintext
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.

Verify the secret with the database information is created with the following command:

```shell
kubectl describe secret app-postgres
```

Sample Output:

```plaintext
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](https://cloud.google.com/sql/docs/postgres/connect-kubernetes-engine) if you
would like to connect to the newly provisioned Postgres database instance on CloudSQL.
