Remove the firewall rule previously created to create the database from AZ CLI.

As the access from VMs to the database will use the private endpoint connection, we don't need it anymore. Was required just to be able to connet to MySQL from AZ CLI and create the Wordpress database.

az mysql server firewall-rule delete --name AllowAll --resource-group $resourceGroupName --server-name $mysqlServerName -y

Generate cloud-init

At this step the cloud-init will be generated to create the configuration inside the VMs and install required packages.

cat <<EOF > cloud-init.txt
#cloud-config
package_upgrade: true
packages:
  - nginx
  - php-curl
  - php-gd
  - php-intl
  - php-mbstring
  - php-soap
  - php-xml
  - php-xmlrpc
  - php-zip
  - php-fpm
  - php-mysql
  - nfs-common

write_files:
- path: /tmp/wp-config.php
  content: |
      <?php
      define('DB_NAME', '$dbname');
      define('DB_USER', '$dbuser');
      define('DB_PASSWORD', '$dbpassword');
      define('DB_HOST', '$mysqlServerName.mysql.database.azure.com');
      \$table_prefix = 'wp_';
      if ( ! defined( 'ABSPATH' ) ) {
        define( 'ABSPATH', __DIR__ . '/' );
      }
      require_once ABSPATH . 'wp-settings.php';
      ?>


- path: /tmp/wordpress.conf
  content: |
   server {
      listen 80;
      server_name _;
      root /data/nfs/wordpress;

      index index.html index.htm index.php;

      location / {
          try_files \$uri \$uri/ /index.php\$is_args\$args;
      }

      location ~ \.php$ {
          include snippets/fastcgi-php.conf;
          fastcgi_pass unix:/var/run/php/php7.2-fpm.sock;
      }

      location = /favicon.ico { log_not_found off; access_log off; }
      location = /robots.txt { log_not_found off; access_log off; allow all; }
      location ~* \.(css|gif|ico|jpeg|jpg|js|png)$ {
        expires max;
        log_not_found off;
      }

      location ~ /\.ht {
          deny all;
      }

   }

runcmd: 
  - mkdir -p /data/nfs/wordpress
  - mount -t nfs $storageAccountName.file.core.windows.net:/$storageAccountName/$shareName /data/nfs -o vers=4,minorversion=1,sec=sys
  - wget http://wordpress.org/latest.tar.gz -P /data/nfs/wordpress
  - tar xzvf /data/nfs/wordpress/latest.tar.gz -C /data/nfs/wordpress --strip-components=1
  - cp /tmp/wp-config.php /data/nfs/wordpress/wp-config.php
  - cp /tmp/wordpress.conf  /etc/nginx/conf.d/wordpress.conf
  - chown -R www-data:www-data /data/nfs/wordpress
  - rm /etc/nginx/sites-enabled/default
  - rm /etc/nginx/sites-available/default
  - systemctl restart nginx
EOF

Create a Virtual Machine Scale Set

az vmss create \
  --name $ScaleSetName \
  --resource-group $resourceGroupName \
  --image UbuntuLTS \
  --admin-username azureuser \
  --generate-ssh-keys \
  --instance-count 3 \
  --vnet-name $VNETName \
  --subnet $BackendSubnetName \
  --vm-sku Standard_DS2_v2 \
  --upgrade-policy-mode Automatic \
  --app-gateway $AppGatewayName \
  --custom-data cloud-init.txt \
  --backend-pool-name appGatewayBackendPool \
  --zones 1 2 3

az network public-ip show \
  --resource-group $resourceGroupName \
  --name $AppGWPublicIPAddressName \
  --query [ipAddress] \
  --output tsv

http://application_gateway_public_ip

az vmss scale  --name myScaleSet --new-capacity 5 --resource-group $resourceGroupName

az monitor autoscale create \
  --resource-group $resourceGroupName \
  --resource $ScaleSetName \
  --resource-type Microsoft.Compute/virtualMachineScaleSets \
  --name autoscale \
  --min-count 3 \
  --max-count 10 \
  --count 3

az monitor autoscale rule create \
  --resource-group $resourceGroupName \
  --autoscale-name autoscale \
  --condition "Percentage CPU > 70 avg 5m" \
  --scale out 3

az monitor autoscale rule create \
  --resource-group $resourceGroupName \
  --autoscale-name autoscale \
  --condition "Percentage CPU < 30 avg 5m" \
  --scale in 1