This sample code shows how to deploy an application to the EnSaaS 4.0 environment and connect to the the database (Postgresql) and message broker (RabbitMQ) services provided by the platform.

• Container Orchestration: Kubernetes
• Package Manager: Helm

• Application Architecture
• Ingress Layout
• Quick Start
  • Downloading the Project
  • Installing a Release
  • Retrieving the URL of the Application
• Customizing the Application
  • Building & Pushing the Images
  • Configuring the Helm Chart
  • Installing a Release
• Upgrade & Rollback

$ git clone [email protected]:WISE-PaaS/mqtt-postgres-k8s.git
$ cd mqtt-postgres-k8s/helm-chart

First, make sure you are working in the EnSaaS 4.0 environment.

$ kubectl config get-contexts

Switch to the correct environment if you are not currently in the EnSaaS environment.

$ kubectl config use-context [CONTEXT]

Install the applicaiton to the platform.

$ helm install demo .

Show the list of installed applications.

$ helm ls

Now, you have completed the deployment, and your app is good to go!

$ kubectl get ingress

In the output, you can find the hostname of the application.

$ kubectl get ing
NAME                     HOSTS                                              ADDRESS                      PORTS   AGE
demo-iot-home-dave-lee   iot-home-dave-lee.devspace.eks004.en.internal      10.0.9.4,10.0.9.5,10.0.9.6   80      108s

The naming convention for the HOSTS while you are deploying the app to EnSaaS. You can set up these required valus in your Helm Chart.

{Host}.{Namespace}.{ClusterName}.en.internal

From the HOSTS, you can derive the external URL with the following format:

https://{Host}-{Namespace}-{ClusterName}.sa.wise-paas.com

In this example, we can access the application by going to:

https://iot-home-dave-lee-devspace-eks004.sa.wise-paas.com

$ cd server/
$ docker build {DockerHubAccount}/{ImageName}:{Tag} .
$ docker push {DockerHubAccount}/{ImageName}:{Tag}

$ cd ../iothub-mqtt/
$ docker build {DockerHubAccount}/{ImageName}:{Tag} .
$ docker push {DockerHubAccount}/{ImageName}:{Tag}

$ cd ../helm-chart/

Inside Chart.yaml, customize your Chart Name and Versions.

The Chart Name and Chart Version will be displayed in the helm list as soon as you install a release.

Inside Values.yaml, you can tune the following options:

• namespace

  Set this value according to the namespace that has been created in your workspace.

• replicaCount

  Increase this value to scale out the application.

  

• repository

  Your DockerHub account

• imageNmae & tag

  Change these values if you have built your own images.

• resources

  Fine-tune resource usage according to your need.

  

• global.database.secretName

  Name of the secret that you will use for these deployments.

  Naming convention for the secret: {ChartName}-{Namespace}-secret

  {ChartName} is defined in the Chart.yaml inside the helm-chart directory. The example shown below has iot-home-k8s as the Chart name and devspace as the namespace.

• global.url.host

  Naming convention for host: .{Namespace}.{ClusterName}.en.internal

  en.internal at the end is a fixed string. And also notice that there is dot (.) at the beginning of the host value. In the following example, once you install a helm release, this host will be combined with the ingress.hosts[0].host and become the external URL as iothome.devspace.eks004.sa.wise-paas.com. We can see that the en.internal has been replaced with sa.wise-paas.com.

  

As mentioned in the first section, install the release using helm install once you have finished your customized.

# Under helm-chart directory
$ helm install {ReleaseName} .

One way to upgrade your release is to set up all the values that you want change in a file and then apply this file using the following command.

$ helm upgrade [RELEASE] [CHART] -f [YAML_FILE]

We can use the example file that has been included in this repository as a demonstration.

$ helm upgrade demo . -f newvalue.yaml

Inside newvalue.yaml:

deployParams:
  iothubMqtt:
    replicaCount: 2

This upgrade will scale out the application by adding another Pod that runs the mqtt container.

Now, we can check what velues have been changed.

$ helm get values demo
USER-SUPPLIED VALUES:
deployParams:
  iothubMqtt:
    replicaCount: 2

You can also rollback the Release to the previous Revision using the following command.

Let's check the revision history first.

$ helm history demo
REVISION	UPDATED                 	STATUS    	CHART             	APP VERSION	DESCRIPTION
1       	Wed Feb 19 12:22:56 2020	superseded	iot-home-k8s-0.3.0	1.0.0      	Install complete
2       	Wed Feb 19 13:34:45 2020	superseded	iot-home-k8s-0.3.1	1.0.0      	Upgrade complete
3       	Wed Feb 19 15:21:20 2020	deployed  	iot-home-k8s-0.3.2	1.0.0      	Upgrade complete

Roll back to the revision No. 2.

$ helm rollback demo 2
Rollback was a success! Happy Helming!

Now, check the deployment again and we can see that the application has been scaled in by rolling back to the previous status.