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04 - Logging and Monitoring

Azure Container Apps provides native support for observability through Azure Monitor, Log Analytics, and Application Insights. This guide covers how to configure structured logging and monitor your Spring Boot application in production.

Infrastructure Context

Service: Container Apps (Consumption) | Network: VNet integrated | VNet: ✅

This tutorial assumes a production-ready Container Apps deployment with a custom VNet, ACR with managed identity pull, and private endpoints for backend services.

flowchart TD
    INET[Internet] -->|HTTPS| CA["Container App\nConsumption\nLinux Java 17"]

    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

Monitoring Workflow

graph LR
    APP[Spring Boot App] --> STDOUT[Console Output]
    APP --> OTLP[OpenTelemetry]
    STDOUT --> LOGS[Log Analytics]
    OTLP --> APPI[Application Insights]
    LOGS --> DASH[Azure Monitor Dashboards]
    APPI --> DASH

Prerequisites

  • Existing Azure Container App (created in 02 - First Deploy)
  • Azure CLI 2.57+
  • Azure Monitor Workspace (created automatically with ACA environment)

Structured Logging

For production, Spring Boot should output logs to stdout in a format that's easy for log collectors to parse. JSON format is recommended.

1. Logback Configuration

The reference application includes a src/main/resources/logback-spring.xml file configured for structured logging.

<!-- Example logback-spring.xml snippet -->
<configuration>
    <appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
        <encoder class="net.logstash.logback.encoder.LogstashEncoder">
            <!-- Custom fields for Azure integration -->
            <field name="containerApp">${CONTAINER_APP_NAME}</field>
            <field name="revision">${CONTAINER_APP_REVISION}</field>
        </encoder>
    </appender>
    <root level="INFO">
        <appender-ref ref="CONSOLE" />
    </root>
</configuration>

2. View Logs via CLI

Stream logs directly from your container app for real-time debugging:

az containerapp logs show \
  --resource-group $RG \
  --name $APP_NAME \
  --follow \
  --tail 100
Expected output 
{"timestamp":"2026-04-05T10:00:00.000Z","level":"INFO","logger":"com.example.demo.DemoApplication","message":"Started DemoApplication in 8.67 seconds","containerApp":"<your-app-name>","revision":"<your-app-name>--xxxxxxx"}

Application Insights Integration

Azure Monitor's Application Insights provides distributed tracing, performance monitoring, and live metrics.

1. Enable Application Insights

The easiest way to enable Application Insights for Spring Boot is using the Java In-Process Agent.

# Add Application Insights Connection String
INSTRUMENTATION_KEY=$(az monitor app-insights component show --app $APP_NAME --resource-group $RG --query "connectionString" --output tsv)

az containerapp update \
  --resource-group $RG \
  --name $APP_NAME \
  --set-env-vars "APPLICATIONINSIGHTS_CONNECTION_STRING=$INSTRUMENTATION_KEY"

2. Spring Boot Actuator

Ensure Spring Boot Actuator endpoints are exposed to provide health and metrics data to Azure Monitor.

# application.yml
management:
  endpoints:
    web:
      exposure:
        include: health,info,metrics,prometheus
  endpoint:
    health:
      show-details: always

Querying Logs with KQL via CLI

Use the Azure CLI to query logs directly from the command line. This is essential for automated monitoring and CI/CD pipelines.

Get Log Analytics Workspace ID

WORKSPACE_ID=$(az monitor log-analytics workspace list \
  --resource-group $RG \
  --query "[0].customerId" \
  --output tsv)

Query Console Logs

# Use the APP_NAME variable set in 02-first-deploy.md
az monitor log-analytics query \
  --workspace $WORKSPACE_ID \
  --analytics-query "ContainerAppConsoleLogs_CL | where ContainerAppName_s == '$APP_NAME' | project TimeGenerated, ContainerAppName_s, Log_s | take 5" \
  --output table
Expected output 
ContainerAppName_s    Log_s                                      TimeGenerated
--------------------  -----------------------------------------  ----------------------------
<your-app-name>       .   ____          _            __ _ _      2026-04-04T16:03:47.659Z
<your-app-name>       /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \    2026-04-04T16:03:47.659Z
<your-app-name>       Started DemoApplication in 8.67 seconds    2026-04-04T16:04:00.123Z

Query Error Logs

az monitor log-analytics query \
  --workspace $WORKSPACE_ID \
  --analytics-query "ContainerAppConsoleLogs_CL | where ContainerAppName_s == '$APP_NAME' | where Log_s contains 'ERROR' | project TimeGenerated, Log_s | take 10" \
  --output table

Query System Logs (Startup Events)

az monitor log-analytics query \
  --workspace $WORKSPACE_ID \
  --analytics-query "ContainerAppSystemLogs_CL | where ContainerAppName_s == '$APP_NAME' | project TimeGenerated, Reason_s, Log_s | take 5" \
  --output table
Expected output 
Log_s                                                                         Reason_s            TimeGenerated
----------------------------------------------------------------------------  ------------------  ----------------------------
Updating containerApp: <your-app-name>                                        ContainerAppUpdate  2026-04-04T16:03:06.835Z
Replica '<your-app-name>--9kvcb6d-...' has been scheduled to run on a node.   AssigningReplica    2026-04-04T16:03:06.835Z
KEDA is starting a watch for revision '<your-app-name>--9kvcb6d'...           KEDAScalersStarted  2026-04-04T16:03:06.835Z

Monitoring Checklist

  • [x] Application logs are written to stdout (not to a local file)
  • [x] Log level is configurable via environment variable (LOGGING_LEVEL_ROOT)
  • [x] Application Insights is receiving data (Traces, Exceptions, Requests)
  • [x] Spring Boot Actuator endpoints are accessible and returning metrics

Avoid excessive logging

In a high-throughput production environment, avoid logging large request/response bodies or sensitive information (PII). Use INFO level for normal operations and DEBUG only when troubleshooting.

See Also

Sources