Lab: Helm Setup and Deploy Application

In this lab we will setup Helm in our AKS cluster and deploy our application with Helm charts.

Prerequisites

Helm Version 3+
Clone this repo in Azure Cloud Shell.
Complete previous labs:
- Azure Kubernetes Service
- Build Application Components in Azure Container Registry

Instructions

Note: The following lab assumes Helm version 3. Run the following to confirm your Helm version: ```bash helm version

Example Output:

version.BuildInfo{Version:”v3.8.0”, GitCommit:”d14138609b01886f544b2025f5000351c9eb092e”, GitTreeState:”clean”, GoVersion:”go1.17.5”} ```

Review the Helm Chart components

In this repo, there is a folder for charts with a sub-folder for each specific app chart. In our case each application has its own chart.

The values.yaml file has the parameters that allow you to customize release. This file has the defaults, but they can be overridden on the command line.

The templates folder holds the yaml files for the specific kubernetes resources for our application. Here you will see how Helm inserts the parameters into resources with this bracketed notation: eg - ``
Customize Chart Parameters

In each chart we will need to update the values file with our specific Azure Container Registry.
- Get the value of your ACR Login Server:
```
  az acr list -o table --query "[].loginServer" -g $RGNAME

  Result
  -------------------
  youracr.azurecr.io
```
- Replace the acrServer value below with the Login server from previous step. In the Azure Cloud Shell, select the file editor ‘{}’. Navigate to the yaml files below. To save changes, select the elipticals on the right hand side and select Save. You will make this change in all of the charts below:
  
  Replace all acrServer values:
```
  export ACRSERVER=$(az acr list -g $RGNAME -o table --query "[].loginServer" --output json | jq -r '.[]')
  echo "export ACRSERVER=$ACRSERVER" >> ~/workshopvars.env
  find charts -name values.yaml -exec sed -i 's/youracr.azurecr.io/'${ACRSERVER}'/g' {} \;
```
  charts/service-tracker-ui/values.yaml
  
  charts/weather-api/values.yaml
  
  charts/flights-api/values.yaml
  
  charts/quakes-api/values.yaml
  
  charts/data-api/values.yaml
  
  Example:
```
  # Default values for chart

  service:
  type: ClusterIP
  port: 3009

  deploy:
  name: data-api
  replicas: 1
  acrServer: "youracr.azurecr.io"
  imageTag: "1.0"
  containerPort: 3009
```
- Validate that the imageTag parameter matches the tag you created in Azure Container Registry in the previous lab.
- Add imagePullSecret to each deployment.yaml file for each microservice
  
  NOTE: Only do if the Service Principal role assignment in Build Application lab failed. You will need to add the Docker Registry secret that was created to each deployment via a mechanism called an imagePullSecret.
  
  charts/service-tracker-ui/templates/deployment.yaml
  
  charts/weather-api/templates/deployment.yaml
  
  charts/flights-api/templates/deployment.yaml
  
  charts/quakes-api/templates/deployment.yaml
  
  charts/data-api/templates/deployment.yaml
  
  Example Before:
```
  ...

  containers:
    - image: "/hackfest/weather-api:"
      imagePullPolicy: Always

  ...
```
  Example After (2 imagePullSecrets lines added):
```
  ...

  imagePullSecrets:
  - name: regcred
  containers:
    - image: "/hackfest/weather-api:"
      imagePullPolicy: Always

  ...
```
Deploy MongoDB
```
 kubectl apply -f charts/mongo/.
```
Wait for the mongo pod to be in ‘Ready’ state before deploying the rest of the application. You can watch the pod status with the following:
```
 watch kubectl get pods -n hackfest
```

Deploy Charts

Ensure namespace was created earlier:

 kubectl get ns hackfest

 NAME       STATUS    AGE
 hackfest   Active    4m

Install each chart as below (note: the following commands expect your working directory to be /kubernetes-hackfest you may need to return to this if you have changed workind directory in previous steps):

 # Application charts

 helm upgrade --install data-api charts/data-api --namespace hackfest
 helm upgrade --install quakes-api charts/quakes-api --namespace hackfest
 helm upgrade --install weather-api charts/weather-api --namespace hackfest
 helm upgrade --install flights-api charts/flights-api --namespace hackfest
 helm upgrade --install service-tracker-ui charts/service-tracker-ui --namespace hackfest

Initialize application

First check to see if pods and services are working correctly

 kubectl get pod,svc -n hackfest

 NAME                                     READY   STATUS    RESTARTS   AGE
 pod/data-api-5bdc5c94b4-8xfq2            1/1     Running   3          5d3h
 pod/flights-api-77f77464df-n7jb4         1/1     Running   4          5d15h
 pod/quakes-api-7c8b96b594-vm5qd          1/1     Running   4          5d15h
 pod/service-tracker-ui-c4476d778-hpn5q   1/1     Running   3          5d6h
 pod/weather-api-56d6c57b89-cds8v         1/1     Running   4          5d15h

 NAME                         TYPE           CLUSTER-IP     EXTERNAL-IP   PORT(S)          AGE
 service/data-api             ClusterIP      10.0.179.206   <none>        3009/TCP         7d4h
 service/flights-api          ClusterIP      10.0.255.59    <none>        3003/TCP         7d4h
 service/quakes-api           ClusterIP      10.0.122.46    <none>        3012/TCP         7d4h
 service/service-tracker-ui   LoadBalancer   10.0.24.184    40.71.20.1    8080:30757/TCP   5d6h
 service/weather-api          ClusterIP      10.0.124.80    <none>        3015/TCP         7d4h

Browse to the web UI

 kubectl get service service-tracker-ui -n hackfest

 NAME                 TYPE           CLUSTER-IP    EXTERNAL-IP   PORT(S)          AGE
 service-tracker-ui   LoadBalancer   10.0.24.184   40.71.20.1    8080:30757/TCP   5d6h

Open the browser to http://40.71.20.1:8080 (your IP will be different #obvious)

You will need to click “REFRESH DATA” for each service to load the data sets.
Browse each map view and have some fun.

Troubleshooting / Debugging

Make sure Helm version on the client and server are the same to ensure compatibility.

Docs / References

Helm