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    Container Service for Kubernetes:Collect logs for Jobs

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    Container Service for Kubernetes:Collect logs for Jobs

    Last Updated:Mar 27, 2026

    When a Kubernetes Job runs on elastic container instances (virtual nodes), DaemonSets cannot collect its logs. Unlike ECS-based nodes, elastic container instances have no node-level agent. To make matters worse, once a Job completes, its pods exit immediately — before any log agent can flush the data.

    The solution is to persist logs outside the pod lifecycle: mount a File Storage NAS (NAS) file system to the Job so its output is written directly to NAS, then create a separate pod that reads from the same NAS mount and forwards the data to Simple Log Service.

    Data flow: Job → NAS file system → log-collection pod → Simple Log Service

    If Simple Log Service is already enabled for your cluster, an alternative is available: mount a volume to the Job, then configure environment variables to sync log data to Simple Log Service. For details, see Configure log collection for an elastic container instance.

    Prerequisites

    Before you begin, ensure that you have:

    Collect the Job log using NAS

    Step 1: Create the Job

    Create a file named job.yaml with the following content. This example Job calculates pi to 1,000 decimal places and writes the result to /eci/a.log on the NAS mount.

    Replace 04edd48c7c-****.cn-hangzhou.nas.aliyuncs.com with your NAS mount target address.

    apiVersion: batch/v1
kind: Job
metadata:
  name: pi
spec:
  template:
    spec:
      containers:
      - name: pi
        image: resouer/ubuntu-bc
        command: ["sh", "-c", "echo 'scale=1000; 4*a(1)' | bc -l > /eci/a.log 2>&1"] # Saves output to NAS
        volumeMounts:
        - name: log-volume
          mountPath: /eci
          readOnly: false
      restartPolicy: Never
      volumes:
      - name: log-volume
        nfs:
            path: /eci
            server: 04edd48c7c-****.cn-hangzhou.nas.aliyuncs.com
            readOnly: false
  backoffLimit: 4

    Step 2: Deploy the Job to a virtual node

    Apply the Job manifest to the fvt-eci namespace. For instructions on scheduling pods to virtual nodes, see Schedule pods to elastic container instances that are deployed as virtual nodes.

    kubectl apply -f job.yaml -n fvt-eci

    Step 3: Verify the Job completes

    Check pod status to confirm the Job is running:

    kubectl get pod -n fvt-eci

    Wait until the pod status shows Completed before proceeding. At that point, the log file has been written to the NAS file system.

    Step 4: Create the log-collection pod

    Create a file named log-collection.yaml with the following content. This pod mounts the same NAS path and prints the Job's log output.

    Replace 04edd48c7c-****.cn-hangzhou.nas.aliyuncs.com with your NAS mount target address.

    apiVersion: v1
kind: Pod
metadata:
  name: log-collection
spec:
  containers:
  - image: nginx:latest
    name: log-collection
    command: ['/bin/sh', '-c', 'echo &(cat /eci/a.log)'] # Prints the Job log
    volumeMounts:
    - mountPath: /eci
      name: log-volume
  restartPolicy: Never
  volumes:
  - name: log-volume
    nfs:
      server: 04edd48c7c-****.cn-hangzhou.nas.aliyuncs.com
      path: /eci
      readOnly: false

    Deploy the pod:

    kubectl apply -f log-collection.yaml -n fvt-eci

    Next steps