07 - Revisions and Traffic Splitting¶

Azure Container Apps revisions provide immutable deployment snapshots of your .NET application. Use them for safe releases, canary traffic, and quick rollback to a known-good state.

flowchart TD
    INET[Internet] -->|HTTPS| CA["Container App\nConsumption\nLinux .NET 8"]

    subgraph VNET["VNet 10.0.0.0/16"]
        subgraph ENV_SUB["Environment Subnet 10.0.0.0/23\nDelegation: Microsoft.App/environments"]
            CAE[Container Apps Environment]
            CA
        end
        subgraph PE_SUB["Private Endpoint Subnet 10.0.2.0/24"]
            PE_ACR[PE: ACR]
            PE_KV[PE: Key Vault]
            PE_ST[PE: Storage]
        end
    end

    PE_ACR --> ACR[Azure Container Registry]
    PE_KV --> KV[Key Vault]
    PE_ST --> ST[Storage Account]

    subgraph DNS[Private DNS Zones]
        DNS_ACR[privatelink.azurecr.io]
        DNS_KV[privatelink.vaultcore.azure.net]
        DNS_ST[privatelink.blob.core.windows.net]
    end

    PE_ACR -.-> DNS_ACR
    PE_KV -.-> DNS_KV
    PE_ST -.-> DNS_ST

    CA -.->|System-Assigned MI| ENTRA[Microsoft Entra ID]
    CAE --> LOG[Log Analytics]
    CA --> AI[Application Insights]

    style CA fill:#107c10,color:#fff
    style VNET fill:#E8F5E9,stroke:#4CAF50
    style DNS fill:#E3F2FD

Revision Traffic Splitting¶

graph TD
    INGRESS[Ingress] -->|90%| V1[Revision v1]
    INGRESS -->|10%| V2[Revision v2]

Prerequisites¶

• Completed 06 - CI/CD with GitHub Actions
• At least two deployed images/tags in your ACR
• Container App currently running in multiple revision mode or ready to switch

Step-by-step¶

1. Set standard variables

RG="rg-dotnet-guide"
DEPLOYMENT_NAME="main"
BASE_NAME="dotnet-guide"

APP_NAME=$(az deployment group show \
  --name "$DEPLOYMENT_NAME" \
  --resource-group "$RG" \
  --query "properties.outputs.containerAppName.value" \
  --output tsv)

ACR_NAME=$(az deployment group show \
  --name "$DEPLOYMENT_NAME" \
  --resource-group "$RG" \
  --query "properties.outputs.containerRegistryName.value" \
  --output tsv)

ACR_LOGIN_SERVER=$(az deployment group show \
  --name "$DEPLOYMENT_NAME" \
  --resource-group "$RG" \
  --query "properties.outputs.containerRegistryLoginServer.value" \
  --output tsv)

| Command | Purpose |
|---|---|
| `APP_NAME=$(az deployment group show --name "$DEPLOYMENT_NAME" --resource-group "$RG" --query "properties.outputs.containerAppName.value" --output tsv)` | Captures the deployed app name so revision and traffic commands apply to the correct .NET app. |
| `ACR_NAME=$(az deployment group show --name "$DEPLOYMENT_NAME" --resource-group "$RG" --query "properties.outputs.containerRegistryName.value" --output tsv)` | Captures the registry name that stores the revision images referenced during promotion steps. |
| `ACR_LOGIN_SERVER=$(az deployment group show --name "$DEPLOYMENT_NAME" --resource-group "$RG" --query "properties.outputs.containerRegistryLoginServer.value" --output tsv)` | Captures the registry login server used to assemble image tags for new revisions. |

1. Switch to multiple revision mode

By default, Container Apps operate in single revision mode (100% traffic to the latest). To split traffic, you must enable multiple mode.

az containerapp revision set-mode \
  --name "$APP_NAME" \
  --resource-group "$RG" \
  --mode multiple

???+ example "Expected output"

"Multiple"

1. Deploy a new version to create a new revision

az acr build --registry "$ACR_NAME" --image "$BASE_NAME:v3" ./apps/dotnet-aspnetcore

az containerapp update \
  --name "$APP_NAME" \
  --resource-group "$RG" \
  --image "$ACR_LOGIN_SERVER/$BASE_NAME:v3"

???+ example "Expected output"

{
  "latestRevision": "<your-app-name>--xxxxxxx",
  "name": "<your-app-name>",
  "provisioningState": "Succeeded"
}

1. List revisions and identify target names

az containerapp revision list \
  --name "$APP_NAME" \
  --resource-group "$RG" \
  --query "[].{name:name,active:properties.active,createdTime:properties.createdTime}" \
  --output table

???+ example "Expected output"

Name                               Active    CreatedTime
---------------------------------  --------  -------------------------
<your-app-name>--0000001           True      2026-04-04T16:00:00+00:00
<your-app-name>--0000002           True      2026-04-04T16:30:00+00:00

1. Apply canary traffic split (90/10)

Capture the revision names from the list above, then apply traffic weights:

# Replace with your actual revision names from Step 4
OLD_REV="${APP_NAME}--0000001"
NEW_REV="${APP_NAME}--0000002"

az containerapp ingress traffic set \
  --name "$APP_NAME" \
  --resource-group "$RG" \
  --revision-weight "$OLD_REV=90" "$NEW_REV=10"

???+ example "Expected output"

[
  {
    "revisionName": "<your-app-name>--0000001",
    "weight": 90
  },
  {
    "revisionName": "<your-app-name>--0000002",
    "weight": 10
  }
]

1. Verify applied traffic routing

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

???+ example "Expected output"

{
  "fqdn": "<your-app-name>.<env-suffix>.koreacentral.azurecontainerapps.io",
  "traffic": [
    { "revisionName": "<your-app-name>--0000001", "weight": 90 },
    { "revisionName": "<your-app-name>--0000002", "weight": 10 }
  ]
}

1. Rollback instantly if .NET exceptions increase

If the canary revision shows high error rates in Log Analytics, move all traffic back to the stable revision.

az containerapp ingress traffic set \
  --name "$APP_NAME" \
  --resource-group "$RG" \
  --revision-weight "$OLD_REV=100"

1. Deactivate the bad revision

az containerapp revision deactivate \
  --name "$APP_NAME" \
  --resource-group "$RG" \
  --revision "$NEW_REV"

Verify revisions and traffic in Azure Portal¶

[Observed] ca-dotnet-d38538. Container App. Revisions and replicas. Create new revision. Save. Refresh. Deployment mode. Send us your feedback. Learn more. Active revisions. Inactive revisions. Replicas. Name. Date created. Running status. View Logs. Label. Traffic. ca-dotnet-d38538--0000001. 6/4/2026, 5:39:30 PM. Running. View details. Show Logs. 100. %. 1. Show replicas. Application. Revisions and replicas. Containers. Scale. Volumes. Settings. Networking. Ingress. Custom domains. CORS. Security. Monitoring. Log stream. Logs. Console. Alerts. Metrics.

[Inferred] The Deployment mode toolbar action appears to map to the same lever set by az containerapp revision set-mode --mode multiple in Step-by-step Step 2. The Create new revision toolbar action is consistent with the new-revision effect of az containerapp update --image in Step-by-step Step 3. The Active revisions and Inactive revisions tabs are consistent with the revision list and revision deactivate operations in Step-by-step Steps 4 and 8. The Traffic column value 100 % for ca-dotnet-d38538--0000001 appears to map to the per-revision weight set by az containerapp ingress traffic set --revision-weight in Step-by-step Steps 5 and 6.

[Not Proven] Additional revision detail and traffic-split detail are not visible on this view.

Operational Guidance for .NET¶

• Health Probes: Ensure your liveness and readiness probes (/health) are correctly configured so Container Apps doesn't route traffic to a revision that hasn't finished its .NET runtime startup.
• Graceful Shutdown: ASP.NET Core handles SIGTERM signals. When you shift traffic away from a revision, the platform waits for active connections to finish (up to the termination grace period) before stopping the container.
• Session state: If your .NET app uses in-memory sessions, revision changes and replica movement can disrupt state. Use an external provider such as Redis instead of relying on revision traffic splitting or sticky sessions as the state boundary.

Advanced Topics¶

• Blue/Green Deployment: Use labels to route traffic to specific revisions without modifying weights until the "Green" revision is fully verified.
• Dapr service invocation: Dapr can be configured to respect traffic splitting or route to specific revisions using headers.
• Automated Promotion: Use GitHub Actions to increase traffic weight automatically if health checks and telemetry thresholds are met.

See Also¶

• 04 - Logging, Monitoring, and Observability
• 06 - CI/CD with GitHub Actions
• Revision Management Operations

Sources¶

• Revisions in Azure Container Apps (Microsoft Learn)
• Traffic splitting (Microsoft Learn)