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Log Streaming

Use live log streaming when you need to watch the current behavior of a running container app, revision, or replica before you move into longer-window KQL analysis.

Prerequisites

  • A running container app revision
  • Azure CLI with the Container Apps extension installed
  • Permission to read app logs
export RG="rg-aca-prod"
export APP_NAME="app-python-api-prod"

When to Use

  • During active incidents
  • During rollout validation for a new revision
  • When a single replica or container is failing right now

Procedure

Start a basic live stream:

az containerapp logs show \
  --name "$APP_NAME" \
  --resource-group "$RG" \
  --follow

Use filters when you already know the failing scope:

az containerapp logs show \
  --name "$APP_NAME" \
  --resource-group "$RG" \
  --revision "${APP_NAME}--stable" \
  --follow

az containerapp logs show \
  --name "$APP_NAME" \
  --resource-group "$RG" \
  --container "$APP_NAME" \
  --replica "${APP_NAME}--stable-abc123" \
  --follow

Streaming is best for current output. Log Analytics is better when you need:

  • retained history
  • counts and aggregations
  • cross-app or cross-revision queries
  • scheduled-query alerts
flowchart TD
    A[Need log data] --> B{Happening now?}
    B -->|Yes| C[Use az containerapp logs show]
    B -->|No| D[Use Log Analytics query]
    C --> E[Filter by revision, replica, or container]
    D --> F[Summarize trends and alerts]

Verification

  • Confirm that streaming returns recent application output.
  • Confirm that filters isolate the expected revision, replica, or container.
  • Confirm that incident timestamps line up with later workspace queries.

Rollback / Troubleshooting

  • If the stream is empty, verify the app is running and writing to stdout or stderr.
  • If a filtered stream is empty, re-check the exact revision or replica name.
  • If you need historical comparison, switch to Log Analytics instead of continuing to tail.

See Also

Sources