Multi-tenant k8s app example

The goal is to demonstrate one of the ways to deploy a multi tenant app via k8s.

The app is a simple nodejs app that returns the current date and time. The format of the date and time depends on the tenant. The app is deployed as a docker image.

You can however run it locally without docker.

cd multi-tenant-app 
npm i
npm run start:dev

Then visit the following urls:

curl localhost:3000/date

The configuration of the app is done via environment variables. To deploy it for the first tenant, you can run the following command:

TENANT_ID=tenantOne npm run start:dev

And for the second one:

TENANT_ID=tenantTwo npm run start:dev

You can observe that the returned date format is different.

Our goal is to deploy this into k8, using microk8s.

We are going to use the same helm chart with different values file to deploy 2 deployments. In our imaginary case, the second tenant has more usage so we are going to have two replacas for the second tenant.

Build the docker image

docker build -t multi-tenant .

Import inside microk8s

docker save --output multi-tenant.tar multi-tenant
microk8s ctr image import  multi-tenant.tar

# Make sure it is imported
microk8s ctr images ls

Install the helm chart for the multi-tenant app. This will create a deployment and a service for the multi-tenant app for each one of the two tenants.

microk8s.helm install -f multitenant-helm/values_tenantOne.yaml multi-tenant-app-tenantone multi-tenant-helm/
microk8s.helm install -f multitenant-helm/values_tenantTwo.yaml multi-tenant-app-tenanttwo multi-tenant-helm/

Test the app

#Get the ClusterIP of the service out of the listed services
microk8s.kubectl get service

#Then verify the date format is different for each tenant
curl http://<ClusterIP>:3000/date
curl http://<ClusterIP>:3000/date

Clean up

microk8s.helm delete multi-tenant-app-tenantone
microk8s.helm delete multi-tenant-app-tenanttwo
microk8s ctr images rm docker.io/library/multi-tenant:latest