Connect to MongoDB from Outside Kubernetes

The following procedure describes how to connect to a MongoDB resource deployed by Kubernetes from outside of the Kubernetes cluster.

Create external MongoDB services

Setup firewall

Setup Robo3T

Connecting to MongoDB replicaset PRIMARY member

Create external MongoDB services

By default, MongoDB is internally accessible on port 27017. In Kubernetes, if you want to expose a port to the outside world, you can use Service with Type NodePort.

Step 1: Lookup the swimlane namespace and save it as an environment variable

$ kubectl get ns $ export NAMESPACE=<swimlane-namespace>

Step 2: Create new service for mongo pod 0

$ vi mongodb-service-0.yaml apiVersion: v1 kind: Service metadata: name: mongodb-service-0 labels: app: mongodb-replicaset spec: type: NodePort selector: statefulset.kubernetes.io/pod-name: swimlane-sw-mongo-0 ports: - port: 27017 nodePort: 32000 $ kubectl apply -f mongodb-service-0.yaml -n $NAMESPACE

In line nodePort: 32000, we specified the external port. There, any port from the range 30000-32767 can be used.

Step 3: Create new service for mongo pod 1

$ vi mongodb-service-1.yaml apiVersion: v1 kind: Service metadata: name: mongodb-service-1 labels: app: mongodb-replicaset spec: type: NodePort selector: statefulset.kubernetes.io/pod-name: swimlane-sw-mongo-1 ports: - port: 27017 nodePort: 32001 $ kubectl apply -f mongodb-service-1.yaml -n $NAMESPACE

In line nodePort: 32001, we specified the external port. There, any port from the range 30000-32767 can be used.

Step 4: Create new service for mongo pod 2

$ vi mongodb-service-2.yaml apiVersion: v1 kind: Service metadata: name: mongodb-service-2 labels: app: mongodb-replicaset spec: type: NodePort selector: statefulset.kubernetes.io/pod-name: swimlane-sw-mongo-2 ports: - port: 27017 nodePort: 32002 $ kubectl apply -f mongodb-service-2.yaml -n $NAMESPACE

For the line "nodePort: 32002", we specified the external port. From there, any port from the range 30000-32767 can be used.

Step 5: Confirm services are working kubectl get svc -l app=mongodb-replicaset -n $NAMESPACE

Setup firewall

Step 1: Lookup IP addresses

kubectl get nodes -o wide

Step 2: Open firewall to nodePort(s)

You need to use the IP address of any node and grant TCP access to ports from the nodePort line, not from the port line. In our example, we need to open ports 32000, 320001, and 320002.

Setup Robo3T

Now, you can connect to MongoDB using Robo3T or any other client tools using the node IP addresses on which you opened ports 32000, 320001, and 320002. NOTE: Once Swimlane's Mongo version is updated to 4.2.2, you also need to upgrade Robo3T to 1.3.1. Older versions of Robo3T will be unable to connect to Mongo 4.2.2

Step 1 : Create a new MongoDB Connections for swimlane-sw-mongo-0

Name: swimlane-sw-mongo-0

Address: <node internal ip>:32000

Authentication: Enable

Step 2 : Create a new MongoDB Connections for swimlane-sw-mongo-1

Name: swimlane-sw-mongo-1

Address: <node internal ip>:32001

Step 3 : Create a new MongoDB Connections for swimlane-sw-mongo-2

Name: swimlane-sw-mongo-2

Address: <node internal ip>:32002

Note:

Enable Authentication and SSL

Connecting to MongoDB replicaset PRIMARY member

Step 1: Lookup the swimlane namespace and save it as an environment variable

$ kubectl get ns $ export NAMESPACE=<swimlane-namespace>

Step 2: Lookup MongoDB Admin password

$ export MONGO_ADMIN_PASSWORD= <Password_Here> # confirm the export $ echo $MONGO_ADMIN_PASSWORD

Step 3: Determine MongoDB replica set PRIMARY member

kubectl -n $NAMESPACE exec swimlane-sw-mongo-0 -- mongo -u Admin -p $MONGO_ADMIN_PASSWORD --authenticationDatabase admin --ssl --sslAllowInvalidHostnames --sslAllowInvalidCertificates admin --eval="rs.status();" | grep PRIMARY -B5

From the output, note the name of the mongo pod (swimlane-sw-mongo-0 or swimlane-sw-mongo-1 or swimlane-sw-mongo-2) with stateStr is equal to PRIMARY.

Step 4: Access MongoDB replicaset member PRIMARY from Robo3T

Now that you know which pod is running the MongoDB replicaset member PRIMARY, use the corresponding MongoDB connections created above to connect to the member.