Update the container image

Overview

To release a new version with a different tag, update the configured image tag with the CLI. App Service restarts the web app automatically and pulls the new image on each instance.

Short notes (exam revision)

• Change tag → az webapp config container set --container-image-name ...
• New/different tag = App Service restarts and pulls automatically
• Same tag (latest) overwritten = App Service does not detect the change by itself
• To pick up same-tag updates: manual restart or continuous deployment webhook
• On restart, docker pull runs and pulls only changed layers

Update with a new tag

az webapp config container set \
  --resource-group myResourceGroup \
  --name myDocumentProcessor \
  --container-image-name myregistry.azurecr.io/docprocessor:v2

App Service restarts and pulls docprocessor:v2 on every instance.

Same-tag updates (for example latest)

If you push a new image to the same tag, App Service does not detect the change automatically. Behavior on restart:

• Runs docker pull
• Pulls only changed layers
• Uses cached layers when nothing changed

To get the new bits for the same tag:

1. Restart the web app manually, or
2. Enable continuous deployment so a registry webhook triggers the restart

Use cases

• Promote AI API docprocessor:v1 → docprocessor:v2 with a deterministic tag bump
• Hotfix pushed to latest during a lab — know you must restart or CD, not just push
• Rollout script that only changes --container-image-name and relies on automatic restart

Exam tips

• Different tag → config container set is enough (auto restart)
• Same tag → not auto-detected; restart or CD required
• Prefer versioned tags for reliable, exam-safe deployments

Learn more

• Update a custom container
• az webapp config container
• AI-200 study guide