Configure Log4jAppender for Kubernetes and Log Service

This topic describes how to configure a YAML file to export the logs of a Container Service for Kubernetes (ACK) cluster to Log Service, without the need to modify the application. In addition, an application that can be managed through API operations is deployed in the ACK cluster. The application is used to generate logs for testing purposes.

1. Configure Log4jAppender in Log Service.
   1. Create a project in Log Service.
      In this example, a project named k8s-log4j is created in the China (Hangzhou) region where the ACK cluster is deployed. For more information, see Create a project.

      Note We recommend that you create a project in the region where the ACK cluster is deployed. When a Log Service project and an ACK cluster are deployed in the same region, logs are transmitted within the internal network. This enables real-time collection and quick retrieval of log data. This also avoids cross-region transmission, which requires additional bandwidth and time costs.

      
   2. Create a Logstore for the k8s-log4j project.
      In this example, a Logstore named k8s-logstore is created. For more information, see Create a Logstore.
   3. After the k8s-logstore Logstore is created, a dialog box appears, which shows instructions on how to use the Data Import wizard.
      
   4. Select Log4jAppender under Custom Code and configure the settings by performing the steps that are provided on the page.
      In this example, Log4jAppender is configured with the default settings. You can also customize the settings to meet your business requirements.
2. Configure Log4jAppender for the ACK cluster.
   In this example, the demo-deployment and demo-Service files are used.
   1. Connect to your ACK cluster.
      For more information, see Use SSH to connect to a Kubernetes cluster or Use kubectl to connect to an ACK cluster.
   2. Obtain the demo-deployment.yaml file and configure the JAVA_OPTS environment variable.
      The following is a sample template of the demo-deployment.yaml file:

      apiVersion: apps/v1
      kind: Deployment
      metadata:
        name: log4j-appender-demo-spring-boot
        labels:
          app: log4j-appender
      spec:
        replicas: 1
        selector:
          matchLabels:
            app: log4j-appender
        template:
          metadata:
            labels:
              app: log4j-appender
          spec:
            containers:
            - name: log4j-appender-demo-spring-boot
              image: registry.cn-hangzhou.aliyuncs.com/jaegertracing/log4j-appender-demo-spring-boot:0.0.2
              env:
                - name: JAVA_OPTS                ## Take note of the following fields
                  value: "-Dproject={your_project} -Dlogstore={your_logstore} -Dendpoint={your_endpoint} -Daccess_key_id={your_access_key_id} -Daccess_key={your_access_key_secret}"
              ports:
              - containerPort: 8080

      Note The following information is displayed:

      • -Dproject: the name of your project in Log Service. In this example, the name of the project is k8s-log4j.
      • -DlogStore: the name of your Logstore in Log Service. In this example, the name of the Logstore is k8s-logstore.
      • -Dendpoint: the service endpoint of Log Service. You must configure the service endpoint based on the region where the Log Service project is deployed. For more information, see Service endpoints. In this example, the service endpoint is cn-hangzhou.log.aliyuncs.com.
      • -Daccess_key_id: your AccessKey ID.
      • -Daccess_key: your AccessKey secret.
   3. Run the following command to create a Deployment:

      kubectl create -f demo-deployment.yaml

   4. Obtain the demo-Service.yaml file and run the following command to create a Service:
      You do not need to modify the configurations in the demo-Service.yaml file.

      kubectl create -f demo-service.yaml

3. Generate Kubernetes cluster logs.
   You can run the kubectl get command to view the Deployment status of the related resource objects. After the Deployment and Service are deployed, run the kubectl get svc command to check the external IP address of the Service, which is EXTERNAL-IP.

   Command:

   kubectl get svc

   Output:

   NAME                      TYPE           CLUSTER-IP    EXTERNAL-IP      PORT(S)          AGE
   log4j-appender-demo-spring-boot-svc   LoadBalancer   172.21.XX.XX   120.55.XXX.XXX   8080:30398/TCP   1h

   In this example, you can run the login command to generate Kubernetes cluster logs, in which K8 S_SERVICE_IP is EXTERNAL-IP.

   Note For a complete list of API operations, see GitHub log4j-appender-demo.

   curl http://${K8S_SERVICE_IP}:8080/login?name=bruce

4. View logs in Log Service
   1. In the Projects section of the Log Service console, find and click the k8s-log4j project to go to the details page of the project.
   2. Click the icon on the right side of the k8s-logstore Logstore and select Search & Analysis to view the logs of the Kubernetes cluster.