Implementing Azure Load Balancer for web traffic

Posted on by Panther

Introduction

Azure Load Balancer is a highly available and scalable load balancing service provided by Microsoft Azure to distribute incoming internet traffic across multiple virtual machines or cloud services. With the use of Azure Load Balancer, we can efficiently handle high traffic loads and prevent downtime for our cloud application. In this tutorial, we will implement Azure Load Balancer for web traffic to ensure high availability, scalability, and the distribution of traffic across multiple virtual machines.

Prerequisites

Before implementing Azure Load Balancer, we need to ensure the following prerequisites:

  • A valid Azure account
  • Virtual machines (VMs) deployed in Azure
  • At least two VMs deployed in a single Availability Set or a Virtual Machine Scale Set
  • Installed web servers such as Apache or Nginx on VMs
  • Public IP addresses assigned to VMs

If you haven’t already done so, please ensure that you have satisfied the above prerequisites.

Overview of Azure Load Balancer

Azure Load Balancer is a Layer 4 (TCP/UDP) load balancer that provides high availability by evenly distributing incoming traffic over multiple virtual machines. It works by analyzing the incoming traffic and choosing the appropriate virtual machine to handle the request based on the configured rule sets.

Azure Load Balancer supports two modes of distribution:

  • Default, which is used for distributing traffic equally across all available virtual machines
  • Source IP hash, which distributes traffic based on the client IP address, allowing traffic from the same client to be directed to the same virtual machine.

Azure Load Balancer also provides support for various protocols, including TCP, UDP, and HTTP/HTTPS. This makes it possible to use it for different types of applications, such as web servers, database servers, and custom applications.

Step-by-Step Guide

In this step-by-step guide, we will implement Azure Load Balancer for web traffic. We will assume that you have created at least two VMs with web servers installed, and they are assigned static public IP addresses.

If you don’t have any VMs set up in Azure, you can follow Microsoft Azure’s documentation to create them.

Step 1: Create an Azure Load Balancer

Open the Azure portal and navigate to the “Load Balancers” option in the left-hand menu. Then click on the “Add” button.

Create Load Balancer

Configure the following settings:

  • Subscription: Select the subscription that contains your VMs.
  • Resource group: Choose or create a new resource group to hold your load balancer.
  • Name: Give your load balancer a name.
  • Region: Choose the region where you want your load balancer to be deployed.
  • Type: Choose “Public” or “Internal” depending on whether you want to expose the endpoints publicly or privately.
  • SKU: Choose a standard tier SKU for your load balancer.

Configure Load Balancer Settings

Once the configuration is complete, click on the “Review + create” button to proceed. Then, click “Create” to deploy your load balancer.

Step 2: Create a Backend Pool

Now we need to create a backend pool for the load balancer to distribute traffic to. This backend pool will contain the IP addresses of the VMs that will serve as web servers.

Click on the “Backend pools” option in the “Settings” menu of your load balancer. Then click on the “Add” button to create a new backend pool.

Create Backend Pool

Configure the following settings:

  • Name: Give the backend pool a name.
  • Associated health probe: Choose a health probe to monitor the health of the VMs in the backend pool.
  • Add backend pool: Add the IP addresses of the VMs that will serve as web servers.

Configure Backend Pool Settings

Once the configuration is complete, click the “Add” button to create the backend pool.

Step 3: Create a Health Probe

To ensure that the backend pool only contains healthy VMs, we need to create a health probe. This health probe will actively monitor the health of the VMs and remove any unhealthy VMs from the backend pool.

Click on the “Health probes” option in the “Settings” menu of your load balancer. Then click on the “Add” button to create a new health probe.

Create Health Probe

Configure the following settings:

  • Name: Give the health probe a name.
  • Protocol: Choose the protocol used by your web servers. For example, HTTP or HTTPS.
  • Port: Choose the port used by your web servers. For example, port 80 or port 443.
  • Interval: Choose the interval at which the health probe will check the health of the backend VMs.
  • Unhealthy threshold: The number of consecutive failed health probes required to mark a VM as unhealthy.
  • Path: Specify the path of the health check endpoint on the web server.

Configure Health Probe Settings

Once the configuration is complete, click the “Add” button to create the health probe.

Step 4: Create a Load Balancing Rule

Now that our backend pool and health probe are created, we need to create a load balancing rule. This rule will define how traffic will be distributed to the backend pool.

Click on the “Load balancing rules” option in the “Settings” menu of your load balancer. Then click on the “Add” button to create a new load balancing rule.

Create Load Balancing Rule

Configure the following settings:

  • Name: Give the load balancing rule a name.
  • Protocol: Choose the protocol used for load balancing. For example, HTTP or HTTPS.
  • Frontend IP address: Choose the IP address associated with the load balancer.
  • Frontend port: Choose the port associated with the load balancer.
  • Backend pool: Choose the backend pool created earlier.
  • Health probe: Choose the health probe created earlier.

Configure Load Balancing Rule Settings

Once the configuration is complete, click the “Add” button to create the load balancing rule.

Step 5: Configure Network Security Group

To allow traffic to flow through the load balancer to the backend pool, we need to configure the network security group associated with the backend VMs.

Click on the “Network security group” option in the left-hand menu. Then click on the network security group associated with the backend VMs.

Click Network Security Group

Then click on the “Inbound security rules” option in the “Settings” menu. Click on the “Add” button to create a new inbound security rule.

Create Inbound Security Rule

Configure the following settings:

  • Name: Give the inbound security rule a name.
  • Protocol: Choose the protocol used for web traffic. For example, HTTP or HTTPS.
  • Source: Choose the source range of IP addresses that should be allowed to access the web servers.
  • Destination: Choose the destination IP address of the backend pool.
  • Destination port range: Choose the port range used for web traffic. For example, port 80 or port 443.

Configure Inbound Security Rule Settings

Once the configuration is complete, click the “Add” button to create the inbound security rule.

Step 6: Test the Load Balancer

After completing the above steps, your Azure Load Balancer should be ready to distribute traffic evenly across the backend VMs. You can test the load balancer by navigating to the public IP address associated with your load balancer.

Conclusion

In this tutorial, we have implemented Azure Load Balancer for web traffic. We created a load balancer, a backend pool, a health probe, a load balancing rule, and configured the network security group to allow traffic to flow through to the backend pool. With these steps complete, we have successfully created a highly available, scalable, and reliable load balancing solution for our cloud application.

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