Elastic Container Instance:Collect logs by using environment variables

Background information

Simple Log Service is an end-to-end data logging service. You can use Simple Log Service to collect, consume, deliver, query, and analyze log data without performing further development. For more information, see What is Simple Log Service?

Prerequisites

Simple Log Service is activated for the ACK Serverless cluster. Log on to the Simple Log Service console. If Simple Log Service is not activated for the cluster, you are prompted to follow on-screen instructions to activate the service.

Note

• You can use environment variables to configure log collection only when you create an elastic container instance. The log-related environment variables that you pass in when you update an elastic container instance do not take effect.

• If you no longer use a custom project or Logtail configuration, delete the project or Logtail configuration in a timely manner to avoid unnecessary costs.

Configuration description

The prefix of the name of a log environment variable is in the aliyun_logs_{key} format. The following table describes environment variables that can be configured.

Configuration example

1. Connect to your Kubernetes cluster.

2. Create an application.

   You can specify log-related configurations in the environment variables of a container. The following sample YAML file describes how to create a Deployment. In the example, relevant commands are run to continuously display the stdout and log files after the container is started.

   apiVersion: apps/v1
   kind: Deployment
   metadata:
     labels:
       app: sls
     name: eci-sls-demo
   spec:
     replicas: 1
     selector:
       matchLabels:
         app: sls
     template:
       metadata:
         labels:
           app: sls
           alibabacloud.com/eci: "true" 
       spec:
         containers:
         - image: registry-vpc.cn-beijing.aliyuncs.com/eci_open/alpine:3.5
           imagePullPolicy: Always
           args:
           - -c
           - mkdir -p /log;while true; do echo hello world; date; echo hello sls >> /log/alpine.log; sleep 1;done
           command:
           - /bin/sh
           name: alpine
           env:
           # Configure a project or use the default project.
           - name: aliyun_logs_test-stdout_project
             value: k8s-log-c21492
           - name: aliyun_logs_test-file_project
             value: k8s-log-c21492
           # Configure a machine group or use the default machine group.
           - name: aliyun_logs_test-stdout_machinegroup
             value: k8s-group-app-alpine
           - name: aliyun_logs_test-file_machinegroup
             value: k8s-group-app-alpine
           # Collect stdout logs to a Logstore that is named test-stdout. The collection path is stdout.
           - name: aliyun_logs_test-stdout
             value: stdout
           # Collect logs in the /log/*.log directory to a Logstore that is named test-file. The collected objects are all .log files in the /log directory.
           - name: aliyun_logs_test-file
             value: /log/*.log
           # Specify the retention period of logs. The setting is valid only for the Logstore that is named test-stdout.
           - name: aliyun_logs_test-stdout_ttl
             value: "7"
           # Specify the number of log shards. The setting is valid only for the Logstore that is named test-stdout.
           - name: aliyun_logs_test-stdout_shard
             value: "2"
           # Mount an emptyDir volume. When the value of the environment variable aliyun_logs_{key} is a directory in the container, mount an emptyDir volume to the directory.
           volumeMounts:
           - name: volume-sls
             mountPath: /log
         volumes:
         - name: volume-sls
           emptyDir: {}

   Create a YAML file that is named test-sls-env.yaml, copy the preceding template to the YAML file, and then run the following command to create an application:

   kubectl create -f test-sls-env.yaml

3. Check the status of the application.

   kubectl get pod

   Expected output:

   NAME                             READY   STATUS    RESTARTS   AGE
   eci-sls-demo-b97bbd7d6-z9twz     1/1     Running   0          2m45s

4. View logs.

   1. Log on to the Simple Simple Log Service console.

   2. Click the name of the project.

   3. Find the Logstore in which the logs of your containers are stored. Click the name of the Logstore to view the logs.

      • Collection of stdout logs

        

      • Collection of text logs