DocumentDB Kubernetes Operator

The DocumentDB Kubernetes Operator is an open-source project to run and manage DocumentDB on Kubernetes. DocumentDB is the engine powering vCore-based Azure Cosmos DB for MongoDB. It is built on top of PostgreSQL and offers a native implementation of document-oriented NoSQL database, enabling CRUD operations on BSON data types.

As part of a DocumentDB cluster installation, the operator deploys and manages a set of PostgreSQL instance(s), the DocumentDB Gateway, as well as other Kubernetes resources. While PostgreSQL is used as the underlying storage engine, the gateway ensures that you can connect to the DocumentDB cluster using MongoDB-compatible drivers, APIs, and tools.

Note: This project is under active development but not yet recommended for production use. We welcome your feedback and contributions!

Quickstart

This quickstart guide will walk you through the steps to install the operator, deploy a DocumentDB cluster, access it using mongosh, and perform basic operations.

Prerequisites

• Helm installed.
• kubectl installed.
• A local Kubernetes cluster such as minikube, or kind installed. You are free to use any other Kubernetes cluster, but that's not a requirement for this quickstart.
• Install mongosh to connect to the DocumentDB cluster.

Start a local Kubernetes cluster

If you are using minikube, use the following command:

minikube start

If you are using kind, use the following command:

kind create cluster

Install cert-manager

cert-manager is used to manage TLS certificates for the DocumentDB cluster.

If you already have cert-manager installed, you can skip this step.

helm repo add jetstack https://charts.jetstack.io
helm repo update
helm install cert-manager jetstack/cert-manager --namespace cert-manager --create-namespace --set installCRDs=true

Verify that cert-manager is installed correctly:

kubectl get pods -n cert-manager

Output:

NAMESPACE           NAME                                            READY   STATUS    RESTARTS
cert-manager        cert-manager-6794b8d569-d7lwd                   1/1     Running   0
cert-manager        cert-manager-cainjector-7f69cd69f7-pd9bc        1/1     Running   0          
cert-manager        cert-manager-webhook-6cc5dccc4b-7jmrh           1/1     Running   0          

Install documentdb-operator using the Helm chart

The DocumentDB operator utilizes the CloudNativePG operator behind the scenes, and installs it in the cnpg-system namespace. At this point, it is assumed that the CloudNativePG operator is not pre-installed in your cluster.

Use the following command to install the DocumentDB operator:

helm install documentdb-operator oci://ghcr.io/microsoft/documentdb-kubernetes-operator/documentdb-operator --version 0.0.1 --namespace documentdb-operator --create-namespace

This will install the operator in the documentdb-operator namespace. Verify that it is running:

kubectl get deployment -n documentdb-operator

Output:

NAME                  READY   UP-TO-DATE   AVAILABLE   AGE
documentdb-operator   1/1     1            1           113s

You should also see the DocumentDB operator CRDs installed in the cluster:

kubectl get crd | grep documentdb

Output:

documentdbs.db.microsoft.com

Deploy a DocumentDB cluster

Create a single-node DocumentDB cluster:

cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Namespace
metadata:
  name: documentdb-preview-ns
---
apiVersion: db.microsoft.com/preview
kind: DocumentDB
metadata:
  name: documentdb-preview
  namespace: documentdb-preview-ns
spec:
  nodeCount: 1
  instancesPerNode: 1
  documentDBImage: ghcr.io/microsoft/documentdb/documentdb-local:16
  resource:
    pvcSize: 10Gi
  publicLoadBalancer:
    enabled: false
EOF

Wait for the DocumentDB cluster to be fully initialized. Verify that it is running:

kubectl get pods -n documentdb-preview-ns

Output:

NAME                   READY   STATUS    RESTARTS   AGE
documentdb-preview-1   2/2     Running   0          26m

You can also check the DocumentDB CRD instance:

kubectl get DocumentDB -n documentdb-preview-ns

Output:

NAME                 AGE
documentdb-preview   28m

Connect to the DocumentDB cluster

The DocumentDB Pod has the Gateway container running as a sidecar. To keep things simple, the quickstart does not use a public load balancer. So you can connect to the DocumentDB instance directly through the Gateway port 10260. For both minikube and kind, this can be easily done using port forwarding:

kubectl port-forward pod/documentdb-preview-1 10260:10260 -n documentdb-preview-ns

Connect using mongosh:

mongosh 127.0.0.1:10260 -u default_user -p Admin100 --authenticationMechanism SCRAM-SHA-256 --tls --tlsAllowInvalidCertificates

Execute the following commands to create a database and a collection, and insert some documents:

use testdb

db.createCollection("test_collection")

db.test_collection.insertMany([
  { name: "Alice", age: 30 },
  { name: "Bob", age: 25 },
  { name: "Charlie", age: 35 }
])

db.test_collection.find()

Output:

[direct: mongos] test> use testdb
switched to db testdb
[direct: mongos] testdb> db.createCollection("test_collection")
{ ok: 1 }
[direct: mongos] testdb> db.test_collection.insertMany([
...   { name: "Alice", age: 30 },
...   { name: "Bob", age: 25 },
...   { name: "Charlie", age: 35 }
... ])
{
  acknowledged: true,
  insertedIds: {
    '0': ObjectId('682c3b06491dc99ae02b3fed'),
    '1': ObjectId('682c3b06491dc99ae02b3fee'),
    '2': ObjectId('682c3b06491dc99ae02b3fef')
  }
}
[direct: mongos] testdb> db.test_collection.find()
[
  { _id: ObjectId('682c3b06491dc99ae02b3fed'), name: 'Alice', age: 30 },
  { _id: ObjectId('682c3b06491dc99ae02b3fee'), name: 'Bob', age: 25 },
  {
    _id: ObjectId('682c3b06491dc99ae02b3fef'),
    name: 'Charlie',
    age: 35
  }
]

Other options: Try the sample Python app and LoadBalancer service

Connect to DocumentDB using a Python app

In addition to mongosh, you can also use the sample Python program (that uses the PyMongo client) in the GitHub repository to execute operations on the DocumentDB instance. It inserts a sample document to a movies collection inside the sample_mflix database.

git clone https://github.com/microsoft/documentdb-kubernetes-operator
cd documentdb-kubernetes-operator/scripts/test-scripts

pip3 install pymongo

python3 mongo-python-data-pusher.py

Output:

Inserted document ID: 682c54f9505b85fba77ed154
{'_id': ObjectId('682c54f9505b85fba77ed154'),
 'cast': ['Olivia Colman', 'Emma Stone', 'Rachel Weisz'],
 'directors': ['Yorgos Lanthimos'],
 'genres': ['Drama', 'History'],
 'rated': 'R',
 'runtime': 121,
 'title': 'The Favourite MongoDB Movie',
 'type': 'movie',
 'year': 2018}

You can verify this using the mongosh shell:

use sample_mflix
db.movies.find()

Output:

[direct: mongos] testdb> use sample_mflix
switched to db sample_mflix
[direct: mongos] sample_mflix> 

[direct: mongos] sample_mflix> db.movies.find()
[
  {
    _id: ObjectId('682c54f9505b85fba77ed154'),
    title: 'The Favourite MongoDB Movie',
    genres: [ 'Drama', 'History' ],
    runtime: 121,
    rated: 'R',
    year: 2018,
    directors: [ 'Yorgos Lanthimos' ],
    cast: [ 'Olivia Colman', 'Emma Stone', 'Rachel Weisz' ],
    type: 'movie'
  }
]

Use a LoadBalancer service

For the quickstart, you connected to DocumentDB using port forwarding. If you are using a Kubernetes cluster in the cloud (for example, Azure Kubernetes Service), and want to use a LoadBalancer service instead, enable it in the DocumentDB spec as follows:

publicLoadBalancer:
    enabled: true

LoadBalancer service is also supported in minikube and kind.

List the Services and verify:

kubectl get services -n documentdb-preview-ns

This will create a LoadBalancer service named documentdb-service-documentdb-preview for the DocumentDB cluster. You can then access the DocumentDB instance using the external IP of the service.

NAME                                    TYPE           CLUSTER-IP     EXTERNAL-IP     PORT(S)           AGE
documentdb-preview-r                    ClusterIP      10.0.216.38    <none>          5432/TCP          26m
documentdb-preview-ro                   ClusterIP      10.0.31.103    <none>          5432/TCP          26m
documentdb-preview-rw                   ClusterIP      10.0.118.26    <none>          5432/TCP          26m
documentdb-service-documentdb-preview   LoadBalancer   10.0.228.243   52.149.56.216   10260:30312/TCP   27m

If you are using the Python program to connect to DocumentDB, make sure to update the script's host variable with the external IP of your documentdb-service-documentdb-preview LoadBalancer service. Additionally, ensure that you update the default password in the script or, preferably, use environment variables to securely manage sensitive information like passwords.

Delete the DocumentDB cluster and other resources

kubectl delete DocumentDB documentdb-preview -n documentdb-preview-ns

The Pod should now be terminated:

kubectl get pods -n documentdb-preview-ns

Uninstall the DocumentDB operator:

helm uninstall documentdb-operator --namespace documentdb-operator

Output:

These resources were kept due to the resource policy:
[CustomResourceDefinition] poolers.postgresql.cnpg.io
[CustomResourceDefinition] publications.postgresql.cnpg.io
[CustomResourceDefinition] scheduledbackups.postgresql.cnpg.io
[CustomResourceDefinition] subscriptions.postgresql.cnpg.io
[CustomResourceDefinition] backups.postgresql.cnpg.io
[CustomResourceDefinition] clusterimagecatalogs.postgresql.cnpg.io
[CustomResourceDefinition] clusters.postgresql.cnpg.io
[CustomResourceDefinition] databases.postgresql.cnpg.io
[CustomResourceDefinition] imagecatalogs.postgresql.cnpg.io

release "documentdb-operator" uninstalled

Verify that the Pod is removed:

kubectl get pods -n documentdb-preview-ns

Delete namespace, and CRDs:

kubectl delete namespace documentdb-operator

kubectl delete crd backups.postgresql.cnpg.io \
  clusterimagecatalogs.postgresql.cnpg.io \
  clusters.postgresql.cnpg.io \
  databases.postgresql.cnpg.io \
  imagecatalogs.postgresql.cnpg.io \
  poolers.postgresql.cnpg.io \
  publications.postgresql.cnpg.io \
  scheduledbackups.postgresql.cnpg.io \
  subscriptions.postgresql.cnpg.io \
  documentdbs.db.microsoft.com