LEARN. PRACTICE. GROW.Concept and mechanism
An image is a versioned artifact; a reused tag can change content. For production, associate the build, manifest, and approved configuration using a digest or protected unique tag. ACR Tasks can rebuild images after code changes, base-image changes, or a schedule, but the result still needs validation and promotion. App Service can supply runtime configuration without embedding targets and secrets in the image. In Container Apps, revisions represent configuration versions; traffic distribution between ready revisions requires the appropriate mode. Event-driven scaling should use a work-related signal such as backlog and respect downstream capacity. Adding replicas does not automatically fix a saturated database.
Guided application
In a fictional incident, separate image pull, startup, readiness, endpoint selection, and connectivity. ImagePullBackOff occurs before application code: check image reference, networking, and kubelet identity. With ACR using RBAC Registry + ABAC Repository Permissions, do not assume attach-acr with AcrPull; access requires the appropriate Repository Reader role. If pods are Ready but the Service has no endpoints, compare selectors and labels. For slow loading, review the startup probe before removing health controls. Checkpoints on disposable storage do not necessarily survive replica replacement. During an error-producing canary, remove candidate traffic when the previous version and data contract support recovery, retaining diagnostic evidence.
Candidate revision with 10% traffic and errors: recovery depends on an identified, healthy previous revision compatible with the data.
Common pitfalls
Stable tag as frozen content; application identity as kubelet pull identity; more replicas as unlimited capacity; readiness as liveness.
Related topics: Cosmos DB, vectors, and change feed · PostgreSQL, vectors, and caching · Messages, events, and Functions
Control the artifact, configuration, and health before increasing traffic.
Reference: Container Apps revisions and traffic · AI-200 current guide updated2026-05-05; Azure technical documentation2026-09-30