Ingress in Azure Container Apps (ACA): Routing External Traffic to Workloads

Introduction

When deploying containerized applications to the cloud, one of the first challenges developers and DevOps engineers face is exposing those apps to external traffic safely and efficiently. In traditional Kubernetes setups, this involves configuring Ingress Controllers, Load Balancers, or Services. However, with Azure Container Apps (ACA), Microsoft simplifies this entire networking model by offering built-in Ingress support.

In this blog, we will explore:

• What Ingress in ACA is
• Why you need it
• How it works internally
• Different ingress configuration options
• Practical examples for real-world scenarios

By the end, you’ll have a clear understanding of how to securely expose your ACA apps to the internet or keep them private based on your requirements.

What is Ingress in Azure Container Apps?

Ingress in ACA is the entry point for external (or internal) network traffic that needs to reach your containerized app.

Think of Ingress as the front door of your application.

In traditional Kubernetes, configuring ingress often involves setting up an Ingress Controller (like NGINX or Traefik), LoadBalancer services, and external DNS mapping. In ACA, Azure handles all of this for you behind the scenes.

✅ In one line:
ACA Ingress = Managed, built-in HTTP ingress that routes external requests to your containers.

Why Do You Need Ingress?

Whenever your application needs to receive HTTP(s) traffic, such as:

• Public APIs
• Web apps
• Webhooks
• Mobile backends
• Internal APIs (inside your VNet)

You need a way for Azure to route external or internal requests to the correct container running inside ACA.

Types of Ingress in ACA: External vs Internal

Azure Container Apps offers two main ingress visibility modes:

Default Behavior:
If you don’t configure ingress explicitly, ACA apps are internal and not accessible externally.

How Does Ingress Work Technically in ACA?

Here’s what happens when someone accesses your ACA app via its ingress endpoint:

1. Azure manages a built-in Application Gateway / Envoy-based Ingress layer (you don’t see or manage it directly).
2. Incoming HTTP(S) traffic first reaches Azure’s edge load balancers.
3. Traffic routes through the ingress layer of ACA, which then forwards it to the correct container replica.
4. The container responds back through the ingress path.

✅ Important:
You don’t manage ports, load balancer rules, or ingress controllers yourself. ACA does that for you.

Ingress Configuration Options in ACA

You can configure Ingress for an ACA app during creation or update.

Here are the key settings you control:

Example 1: Public (External) Ingress for a Web API

Let’s say you have a Node.js REST API listening on port 3000.

YAML Configuration:

ingress:
  external: true
  targetPort: 3000
  allowInsecure: false

CLI Deployment:

az containerapp create \
  --name public-api \
  --resource-group my-rg \
  --environment my-aca-env \
  --image myregistry.azurecr.io/nodeapi:latest \
  --ingress external \
  --target-port 3000 \
  --transport http

Result:
Azure gives you a public HTTPS endpoint like:
https://public-api.randomhash.region.azurecontainerapps.io

Example 2: Internal Ingress for Private Microservice

For internal microservices that shouldn’t be exposed publicly, use internal ingress.

ingress:
  external: false
  targetPort: 5000

This app is only accessible within the same VNet or from other ACA apps deployed in the same environment.

Summary: Why ACA Ingress is Developer-Friendly

Here’s a quick recap of why Ingress in Azure Container Apps makes life easier:

✅Final Thoughts

Azure Container Apps Ingress abstracts away the complexity of container networking and exposure, letting developers focus on their application logic instead of networking infrastructure.

Whether you’re building public APIs, private microservices, or hybrid workloads, ACA Ingress provides a simple yet powerful way to control traffic flow into your container apps.