Backend pools and health probes in Azure - Mini Project: Build & Apply

Backend pools and health probes

📖 Scenario: You are setting up a simple Azure Load Balancer configuration for a web application. The load balancer will distribute traffic to backend virtual machines. To ensure traffic is only sent to healthy machines, you need to configure backend address pools and health probes.

🎯 Goal: Build an Azure Load Balancer configuration with a backend address pool containing two virtual machines and a health probe that checks their health on port 80.

📋 What You'll Learn

Create a backend address pool named myBackendPool with two IP addresses: 10.0.0.4 and 10.0.0.5.

Create a health probe named myHealthProbe that checks TCP port 80 every 15 seconds with a timeout of 5 seconds.

Associate the health probe with the backend address pool.

Use valid Azure Resource Manager (ARM) JSON syntax.

💡 Why This Matters

🌍 Real World

Load balancers distribute traffic to multiple servers to improve availability and performance. Health probes ensure traffic is only sent to healthy servers.

💼 Career

Understanding backend pools and health probes is essential for cloud engineers managing Azure networking and load balancing.

1

Create the backend address pool

Create a JSON object called backendAddressPool with the name myBackendPool and include two backend IP addresses: 10.0.0.4 and 10.0.0.5.

Azure

{
  "name": "myBackendPool",
  "properties": {
    "backendAddresses": [
      { "ipAddress": "10.0.0.4" },
      { "ipAddress": "10.0.0.5" }
    ]
  }
}
# Your code here

Need a hint?

Use the backendAddresses array inside properties to list the IPs.

2

Create the health probe configuration

Create a JSON object called healthProbe with the name myHealthProbe. Set the protocol to Tcp, the port to 80, the interval to 15 seconds, and the number of unhealthy threshold retries to 2. Set the timeout to 5 seconds.

Azure

{
  "name": "myBackendPool",
  "properties": {
    "backendAddresses": [
      { "ipAddress": "10.0.0.4" },
      { "ipAddress": "10.0.0.5" }
    ]
  }
}

{
  "name": "myHealthProbe",
  "properties": {
    "protocol": "Tcp",
    "port": 80,
    "intervalInSeconds": 15,
    "numberOfProbes": 2,
    "requestPath": null,
    "timeoutInSeconds": 5
  }
}
# Your code here

Need a hint?

Set protocol to Tcp and specify the port and timing values inside properties.

3

Associate the health probe with the load balancer configuration

Create a JSON object called loadBalancer that includes the backendAddressPools array containing myBackendPool and the probes array containing myHealthProbe.

Azure

{
  "backendAddressPools": [
    {
      "name": "myBackendPool",
      "properties": {
        "backendAddresses": [
          { "ipAddress": "10.0.0.4" },
          { "ipAddress": "10.0.0.5" }
        ]
      }
    }
  ],
  "probes": [
    {
      "name": "myHealthProbe",
      "properties": {
        "protocol": "Tcp",
        "port": 80,
        "intervalInSeconds": 15,
        "numberOfProbes": 2,
        "timeoutInSeconds": 5
      }
    }
  ]
}
# Your code here

Need a hint?

Put the backend pool and health probe inside their respective arrays in the load balancer JSON.

4

Complete the load balancer resource with frontend IP configuration

Add a frontendIPConfigurations array to the loadBalancer JSON object with one entry named myFrontEnd and an privateIPAddress of 10.0.0.10.

Azure

{
  "backendAddressPools": [
    {
      "name": "myBackendPool",
      "properties": {
        "backendAddresses": [
          { "ipAddress": "10.0.0.4" },
          { "ipAddress": "10.0.0.5" }
        ]
      }
    }
  ],
  "probes": [
    {
      "name": "myHealthProbe",
      "properties": {
        "protocol": "Tcp",
        "port": 80,
        "intervalInSeconds": 15,
        "numberOfProbes": 2,
        "timeoutInSeconds": 5
      }
    }
  ],
  "frontendIPConfigurations": [
    {
      "name": "myFrontEnd",
      "properties": {
        "privateIPAddress": "10.0.0.10"
      }
    }
  ]
}
# Your code here

Need a hint?

Add the frontend IP configuration as an array with the specified name and IP address.