How to deploy a serverless container with Azure Container Apps

Azure Container Apps runs containers serverlessly on top of Kubernetes and KEDA without exposing that complexity. It supports scale-to-zero, event-driven scaling, and revision-based rollouts, making it a strong middle ground between Azure Functions and full AKS.

Prerequisites

• An Azure subscription and the Azure CLI.
• A container image in a registry (ACR or Docker Hub).

Steps

1. Install the extension

az extension add --name containerapp --upgrade
az provider register --namespace Microsoft.App

2. Create an environment

The environment is a secure boundary that apps share for networking and logging:

az containerapp env create --name app-env --resource-group rg-app --location eastus

3. Deploy the app

az containerapp create --name web --resource-group rg-app --environment app-env \
  --image myregistry.azurecr.io/web:1 --target-port 8080 --ingress external

4. Configure ingress

External ingress assigns a public HTTPS URL with a managed certificate. Use internal ingress for service-to-service calls that should not be public.

5. Set scale rules

Scale on HTTP concurrency or a queue depth, and allow scale to zero:

az containerapp update --name web --resource-group rg-app \
  --min-replicas 0 --max-replicas 10 --scale-rule-name http --scale-rule-http-concurrency 50

6. Roll out a revision

Each config or image change creates a revision. Run multiple revisions and split traffic for canary releases:

az containerapp ingress traffic set --name web --resource-group rg-app \
  --revision-weight latest=20 <previous-revision>=80

Verification

Call the app's ingress URL and confirm a response. Stop sending traffic and confirm replicas drop to zero after the cooldown (no billing while idle). Deploy a new image, split traffic, and confirm both revisions serve in the expected proportion.

Next Steps

Add Dapr for service discovery and pub/sub, bind secrets from Key Vault, and connect to a private VNet for backend access.