Go Voting App

Overview

A simple web app consisting of a Go (lang) server and Redis store, deployed to Azure Kubernetes Service (AKS).

Voting

POST a vote

POST /vote/dogs
# or 
POST /vote/cats

GET votes

GET /votes

Running on Docker

docker-compose up -d

Create a Kubernetes Cluster

Option 1: Create Kubernetes Cluster with Terraform

Create an AZ service principal.

az ad sp create-for-rbac --name <service_principal_name> --role Contributor

Store the result somewhere as we'll need appId and password later for client_id and client_secret respectively.

$env:ARM_CLIENT_ID="<service_principal_app_id>"
$env:ARM_SUBSCRIPTION_ID="<azure_subscription_id>"
$env:ARM_TENANT_ID="<azure_subscription_tenant_id>"
$env:ARM_CLIENT_SECRET="<service_principal_password>"
$env:TR_VAR_client_secret="<service_principal_password>"
$env:TR_VAR_client_id="<service_principal_app_id>"

Create the storage backend for terraform state.

cd ./infra/create-remote-storage
terraform init
terrmaform apply

Copy the storage account name and an access key from the Azure CLI

az storage account list --query "[].name"
az storage account keys list --resource-group tfstate --account-name <account name>

Initialize terraform pointed to our new storage backend.

$ terraform init -backend-config="storage_account_name=<account name>" -backend-config="container_name=tfstate" -backend-config="access_key=<access key>" -backend-config="key=codelab.microsoft.tfstate"
...
You may now begin working with Terraform. 

Change to the infra directory

cd ..

Verify that terraform will create the correct resources.

terraform plan -out out.plan

...
Terraform will perform the following actions:

# azurerm_kubernetes_cluster.k8s will be created
+ resource "azurerm_kubernetes_cluster" "k8s" {
...

Apply the terraform plan. This will take a long time, get yourself a drink.

terraform apply out.plan

Option 2: Crate Kubernetes cluster using Azure CLI

First you will need to setup a service principal which has the correct roles required to create the cluster and pull from the container registry.

Get full ACR id

az acr show --name bensacr --query "id"

Create a service principal, copy the and username as you'll need these later.

az ad sp create-for-rbac --name acr-service-principal --scopes <acrName> --role acrpull --query "password"
az ad sp list --display-name acr-service-principal --query "[].appId"

Login to docker with the acr service principal.

docker login bensacr.azurecr.io --username <appId> --password=<password>

Finally, create the cluster!

az aks create --resource-group myResourceGroup --name myAKSCluster  --node-count 2 --generate-ssh-keys --attach-acr bensacr --service-principal <appId> --client-secret <password>

Install the AKS CLI (kubectl)

az aks install-cli

Configure kubectl with Azure credentials

az aks get-credentials --resource-group myResourceGroup --name myAKSCluster

List Nodes

$ kubectl get nodes
NAME                                STATUS   ROLES   AGE     VERSION
aks-nodepool1-10041079-vmss000000   Ready    agent   9m16s   v1.20.9
aks-nodepool1-10041079-vmss000001   Ready    agent   9m34s   v1.20.9

Push app image to Azure container registry

Build and tag image

docker build --tag go-voting-app .
docker tag go-voting-app:latest bensacr.azurecr.io/go-voting-app:latest

Create a container registry. Note that <acrName> is your globally unique registry name.

az acr create --resource-group myResourceGroup --name <acrName> --sku Basic

Push to container registry

az acr login --name <acrName>
docker push <acrName>/go-voting-app:latest

Verify the image has been pushed

az acr repository list --name <acrName> --output table

Deploy to Kubernetes

Run these commands from the k8s-configuration directory.

Create a secret for the redis password. Add your base64 encoded password to secrets.template.yaml, rename the file to secrets.yaml and apply changes to the cluster.

kubectl apply -f ./secrets.yaml

Create a new k8s deployment

$ kubectl apply -f .\deployment.yaml
deployment.apps/voting-redis created
service/voting-redis created
deployment.apps/go-voting-app created
service/go-voting-app created

Obtain the external IP

$ kubectl get service go-voting-app
NAME            TYPE           CLUSTER-IP     EXTERNAL-IP      PORT(S)        AGE
go-voting-app   LoadBalancer   10.0.225.190   52.226.211.179   80:31742/TCP   101s

Check that the website is up and running at the external IP of the service

In future it would be nice to have more production ready features like k8s ingress and a dns name.