Deploy and Configure an Internal Load Balancer in Azure

Lab Overview

In this lab, you’ll learn how to deploy and configure an internal load balancer in Microsoft Azure.

An internal load balancer allows you to distribute network traffic among multiple virtual machines within a private network. This ensures high availability, fault tolerance, and scalability for your internal applications.

You’ll go through the process of configuring frontend and backend pools, setting up inbound rules, and creating health probes to monitor your virtual machines.

By the end of the lab, you will have a fully functional internal load balancer that can manage traffic across your backend servers.

Learning Objectives

Understand how to deploy an internal load balancer in Azure.
Learn how to configure frontend IP settings and static IPs for traffic routing.
Gain hands-on experience setting up backend pools to distribute traffic to virtual machines.
Configure inbound load balancing rules for HTTP traffic.
Set up health probes to monitor the status of backend servers.
Review and manage load balancer settings, including frontend IPs, backend pools, health probes, and load balancing rules.

Exam Relevance

The skills you learn in this lab are necessary to pass the following Azure certification exams:

AZ-104
AZ-305
AZ-700

This feature is available to labITpro Supporters only.

Azure VM Scale Sets — Quick Reference

Fast lookup for orchestration modes, autoscaling, load balancing, updates & CLI.

Core Benefits

Create & manage groups of identical or heterogeneous VMs.
Automatic scaling based on demand or schedule.
Load balance traffic across instances.
HA across fault domains & availability zones.
Pay only for VMs; no charge for scale set itself.

Scale sets can handle up to 1,000 VMs (Marketplace/Gallery images).

Orchestration Modes

Mode	Profile	Best For
Flexible	Standard Azure VMs	New workloads (default)
Uniform	Identical VMs	Legacy large-scale workloads

Flexible: Full standard VM APIs, dynamic mixing (Spot+on-demand), 1,000 VMs. Uniform: Locked after creation; up to 1,000 VMs (Marketplace) or 600 (custom images).

Orchestration Comparison

Feature	Flexible	Uniform
Standard VM APIs	Yes	No
Mix instance types	Yes	No
RBAC per VM	Yes	No
Azure Backup	Yes	No
Site Recovery	Yes	No
Fault domains	1–3	1–5

Autoscaling Metrics

Host metrics: CPU, memory, disk (no agent needed).
Guest metrics: Custom counters (Azure Diagnostics Extension).
App Insights: Application-level performance metrics.
Rules: Min/max capacity, scale-out/in thresholds, cooldown periods.

Autoscale rules use metrics from Load Balancer, Diagnostics, or App Insights.

Load Balancing

Type	Layer	Best For
Internal LB	L4	Backend pools
Public LB	L4	External traffic
App Gateway	L7	HTTP/HTTPS + WAF

Large scale sets (>100 VMs) require Load Balancer Standard SKU.

Availability & Zones

Single zone: All VMs in one availability zone.
Zone-redundant: VMs spread across 1, 2, or 3 zones in region.
Zone balance: Auto-spread VMs evenly across zones (±1 VM).
Fault domains: 1–3 per zone for best-effort resilience.

Use availability zones for datacenter-level failure protection.

Upgrade Policies (Uniform)

Policy	Rollout	Use
Automatic	Batch	App can tolerate disruption
Rolling	Controlled	Gradual, managed updates
Manual	On-demand	Full control; explicit API calls

Flexible mode uses standard VM updates; no built-in rolling.

Application Deployment

Custom image: Preinstall app; faster provisioning.
Custom Script Extension: Download & run scripts post-deploy.
Azure VM Applications: Package & manage centrally (new).
PowerShell DSC: Desired State Configuration for consistency.

Custom images: 600 VMs max; Marketplace images: 1,000 VMs.

Planned Maintenance & Health

Azure Patch Manager: Automated guest OS patching.
Application Health Extension: Monitor app heartbeat; auto-replace unhealthy.
Health probes (Uniform): Monitor via load balancer.
Platform updates coordinated; typically brief interruption.

Deploy an Internal Load Balancer in Azure

Lab Overview

Learning Objectives

Exam Relevance