Configure Simple Log Service

How it works

When you create a workflow cluster, the system creates an SLS project named k8s-log-<clusterid>. All pod logs are collected into a Logstore named workflow-logstore.

Once enabled, you can view logs from the Argo CLI, Argo Server, or Argo UI — regardless of whether the pod is still running.

Limitations

• Compared with oss-artifact-repository, SLS provides automatic log lifecycle management with configurable retention days and powerful query capabilities. To collect logs by using SLS, remove the archiveLogs: true setting.

• After log collection is enabled, you can view workflow logs before the workflow is deleted, even if the pod is deleted.

• If a workflow is persisted to a database, you can download its logs as a ZIP file or view them in the SLS console even after the workflow is deleted. See Persist workflows.

Enable SLS

If the k8s-log-<clusterid> project was not created automatically, create it manually. See Create an SLS project.

Choose one of the following methods:

argo config sls
Please input log retention days. Default is 7 days.
10

Start to config SLS for your cluster.
Created AliyunLogConfig CR workflow-sls-config in default namespace.
Created SLS logstore workflow-logstore in SLS project k8s-log-<clusterid>, log retention days is 10 days

cat << EOF | kubectl apply -f -
apiVersion: log.alibabacloud.com/v1alpha1
kind: AliyunLogConfig
metadata:
  name: workflow-sls-config
  namespace: default
spec:
  lifeCycle: 5           # Log retention period in days
  logstore: workflow-logstore
  logtailConfig:
    configName: workflow-sls-config
    inputType: plugin    # Use the plugin-based input method
    inputDetail:
      plugin:
        inputs:
        - type: service_docker_stdout  # Collect container stdout and stderr
          detail:
            Stdout: true
            Stderr: true
EOF

Verify log collection

After enabling SLS, confirm that logs are being collected:

1. Log on to the SLS console.

2. Find the k8s-log-<clusterid> project.

3. Click workflow-logstore and check that log entries appear.

If no logs appear, check whether the AliyunLogConfig custom resource was created:

kubectl get aliyunlogconfigs -n default

The output should include workflow-sls-config with no error status. If missing or errored, re-run the enable steps or verify RAM user permissions.

Access logs with the Argo CLI

The Argo CLI provides two ways to view workflow logs. The direct method (--sls flag) is recommended because it does not require Argo Server.

You can run kubectl logs <pod-name> to view logs of an existing pod, but this command returns up to 2,000 rows by default. To view more logs or logs for a deleted pod, use one of the following methods.

View logs for workflows persisted to databases

If a workflow is persisted to a database, you can download its logs after the workflow is deleted.

1. Grant the Argo CLI access to your cluster:

   argo config init  # Follow the prompts to enter your AccessKey ID and AccessKey secret.

2. Get the archived workflow UID:

   argo archive list

   Expected output:

   NAMESPACE   NAME                   STATUS      AGE   DURATION   PRIORITY   MESSAGE   P/R/C   PARAMETERS   UID
   default     hello-world-l6c2r      Succeeded   3d    1m         0                    0/0/0                179eaef0-fde3-496f-946d-549e8f******

3. Download workflow logs with the UID:

   argo archive logs 179eaef0-fde3-496f-946d-549e8f******

   The logs are saved as <workflow-name>.zip in the current directory.

View logs in the Argo UI

The Argo UI displays workflow pod logs directly. If a pod is deleted, SLS logs are shown instead of live pod output.

Disable SLS

1. Delete the AliyunLogConfig custom resource:

   kubectl delete aliyunlogconfigs.log.alibabacloud.com workflow-sls-config -n default

2. Log on to the SLS console and delete the workflow-logstore Logstore.

Next steps

• Persist workflows — Store workflow state in a database to retain logs and results after deletion.

• Alibaba Cloud Argo CLI — Download and configure the CLI for full log access.