crossplane

# Crossplane

Crossplane extends Kubernetes to provision and manage cloud infrastructure using Custom Resource Definitions (CRDs).

## Installation

```bash
# Install Crossplane with Helm
helm repo add crossplane-stable https://charts.crossplane.io/stable
helm repo update

helm install crossplane crossplane-stable/crossplane \
  --namespace crossplane-system \
  --create-namespace

# Verify installation
kubectl get pods -n crossplane-system
kubectl api-resources | grep crossplane
```

## AWS Provider

```yaml
# providers/aws-provider.yaml — Install AWS provider
apiVersion: pkg.crossplane.io/v1
kind: Provider
metadata:
  name: provider-aws
spec:
  package: xpkg.upbound.io/upbound/provider-aws-ec2:v1.1.0
---
apiVersion: pkg.crossplane.io/v1
kind: Provider
metadata:
  name: provider-aws-s3
spec:
  package: xpkg.upbound.io/upbound/provider-aws-s3:v1.1.0
---
apiVersion: pkg.crossplane.io/v1
kind: Provider
metadata:
  name: provider-aws-rds
spec:
  package: xpkg.upbound.io/upbound/provider-aws-rds:v1.1.0
```

```yaml
# providers/aws-config.yaml — AWS provider credentials configuration
apiVersion: v1
kind: Secret
metadata:
  name: aws-creds
  namespace: crossplane-system
type: Opaque
stringData:
  credentials: |
    [default]
    aws_access_key_id = AKIA...
    aws_secret_access_key = ...
---
apiVersion: aws.upbound.io/v1beta1
kind: ProviderConfig
metadata:
  name: default
spec:
  credentials:
    source: Secret
    secretRef:
      namespace: crossplane-system
      name: aws-creds
      key: credentials
```

## Managed Resources

```yaml
# resources/s3-bucket.yaml — Provision S3 bucket via Crossplane
apiVersion: s3.aws.upbound.io/v1beta1
kind: Bucket
metadata:
  name: my-app-data
spec:
  forProvider:
    region: us-east-1
    tags:
      Environment: production
      ManagedBy: crossplane
  providerConfigRef:
    name: default
---
apiVersion: s3.aws.upbound.io/v1beta1
kind: BucketVersioning
metadata:
  name: my-app-data-versioning
spec:
  forProvider:
    region: us-east-1
    bucketRef:
      name: my-app-data
    versioningConfiguration:
      - status: Enabled
```

```yaml
# resources/rds-instance.yaml — Provision RDS PostgreSQL via Crossplane
apiVersion: rds.aws.upbound.io/v1beta1
kind: Instance
metadata:
  name: production-db
spec:
  forProvider:
    region: us-east-1
    engine: postgres
    engineVersion: "15"
    instanceClass: db.t3.medium
    allocatedStorage: 100
    storageType: gp3
    storageEncrypted: true
    dbName: appdb
    username: admin
    passwordSecretRef:
      name: db-password
      namespace: default
      key: password
    multiAz: true
    backupRetentionPeriod: 7
    skipFinalSnapshot: false
  writeConnectionSecretToRef:
    name: production-db-conn
    namespace: default
```

## Compositions

```yaml
# compositions/database-definition.yaml — XRD for database abstraction
apiVersion: apiextensions.crossplane.io/v1
kind: CompositeResourceDefinition
metadata:
  name: xdatabases.platform.example.com
spec:
  group: platform.example.com
  names:
    kind: XDatabase
    plural: xdatabases
  claimNames:
    kind: Database
    plural: databases
  versions:
    - name: v1alpha1
      served: true
      referenceable: true
      schema:
        openAPIV3Schema:
          type: object
          properties:
            spec:
              type: object
              properties:
                size:
                  type: string
                  enum: ["small", "medium", "large"]
                engine:
                  type: string
                  enum: ["postgres", "mysql"]
                  default: postgres
              required:
                - size
```

```yaml
# compositions/database-composition.yaml — Compose RDS from XDatabase claim
apiVersion: apiextensions.crossplane.io/v1
kind: Composition
metadata:
  name: database-aws
  labels:
    provider: aws
spec:
  compositeTypeRef:
    apiVersion: platform.example.com/v1alpha1
    kind: XDatabase
  resources:
    - name: rds-instance
      base:
        apiVersion: rds.aws.upbound.io/v1beta1
        kind: Instance
        spec:
          forProvider:
            region: us-east-1
            engine: postgres
            storageEncrypted: true
            skipFinalSnapshot: false
      patches:
        - type: FromCompositeFieldPath
          fromFieldPath: spec.size
          toFieldPath: spec.forProvider.instanceClass
          transforms:
            - type: map
              map:
                small: db.t3.micro
                medium: db.t3.medium
                large: db.r6g.large
        - type: FromCompositeFieldPath
          fromFieldPath: spec.engine
          toFieldPath: spec.forProvider.engine
```

## Claims

```yaml
# claims/my-database.yaml — Developer claims a database through platform API
apiVersion: platform.example.com/v1alpha1
kind: Database
metadata:
  name: orders-db
  namespace: team-a
spec:
  size: medium
  engine: postgres
  compositionSelector:
    matchLabels:
      provider: aws
```

## GCP Provider

```yaml
# providers/gcp-provider.yaml — Install and configure GCP provider
apiVersion: pkg.crossplane.io/v1
kind: Provider
metadata:
  name: provider-gcp
spec:
  package: xpkg.upbound.io/upbound/provider-gcp-storage:v1.0.0
---
apiVersion: gcp.upbound.io/v1beta1
kind: ProviderConfig
metadata:
  name: default
spec:
  projectID: my-gcp-project
  credentials:
    source: Secret
    secretRef:
      namespace: crossplane-system
      name: gcp-creds
      key: credentials.json
```

## Common Commands

```bash
# Check providers
kubectl get providers
kubectl get providerconfigs

# Check managed resources
kubectl get managed
kubectl describe bucket my-app-data

# Check compositions
kubectl get compositions
kubectl get compositeresourcedefinitions
kubectl get composite
kubectl get claim --all-namespaces

# Debug
kubectl get events --field-selector involvedObject.name=my-app-data
crossplane beta trace database orders-db -n team-a
```