Containerized solutions
Where it sits in the route
This module begins the AZ-204 runtime path. It follows shell, Git, packages, ports, HTTP, and the container image concept and comes before App Service container deployment and pipeline promotion.
Plain-language outcomes
You should be able to explain why an image is immutable packaging rather than a running container, trace an image from build to registry to runtime, and choose among ACI and Container Apps for different workload shapes.
Concept sequence and relationships
- A build assembles layers into an image and records a tag or digest.
- Azure Container Registry stores the image; the runtime authenticates before pulling it.
- Azure Container Instances runs an isolated task; Container Apps runs a managed application with revisions, ingress, and scaling.
- A deployment promotes the same tested image into a runtime; Application Insights observes the result.
The registry-to-runtime handoff is an identity and network boundary. A successful image build does not prove that the runtime can pull it. Wrong image references, missing pull permission, unsupported architecture, and blocked ingress are distinct failures.
Worked scenario
A thumbnail worker runs for a few minutes after a message arrives. Package the worker as an image and choose a task-oriented runtime. A customer-facing API needs revisions, ingress, and demand-based scaling, so choose a managed container application. In both cases record the image digest, grant only pull access, and inspect logs at the runtime boundary.
Distinctions and troubleshooting
- Image versus container: a file/package versus a running process.
- ACR versus ACI: storage and distribution versus execution.
- ACI versus Container Apps: isolated task versus managed application lifecycle.
- Registry authorization failure versus application crash: pull logs fail before process logs exist.
Conceptual checkpoint
Draw the build → image → ACR → runtime → telemetry chain, label the identity handoff, and explain which observation proves each stage. Then choose ACI or Container Apps for three workloads and justify the decision.
Hands-on / what to try
Use a local image or a written configuration exercise; do not create Azure resources for this repository task. Record the intended image digest, registry permission, runtime ingress, expected health signal, and cleanup scope. The procedure is designed but not live-verified.
Sources and re-audit
- Implement containerized solutions objectives, skills measured 2026-01-14; checked 2026-08-31.
- Container Instances overview, checked 2026-08-31.
- Container Apps overview, checked 2026-08-31.
Re-audit when image pull authorization, runtime capabilities, ingress, or scaling behavior changes.