Collecting Container Logs Using ICAgent

Notes and Constraints

Using ICAgent to Collect Logs

1. When creating a workload, choose Logging in Container Information.
2. Click to add a log policy.

   The following uses Nginx as an example. Log policies vary depending on workloads.

3. Set Volume Type to hostPath or emptyDir.

   Table 1 Parameters for configuring a log policy

   Parameter	Description
   Volume Type	hostPath: A host path is mounted to the specified container path (mount path). After it is mounted, you can view the container logs that have been saved there. emptyDir: A temporary path of the node is mounted to the specified path (mount path). After it is mounted, any logs in the temporary path that are not reported to AOM by the collector will be lost if the pod is deleted.
   hostPath	Enter a host path, for example, /var/paas/sys/log/nginx.
   Mount Path	Container path (for example, /tmp) that the storage resources will be mounted to. NOTICE: Do not mount a volume to a system directory such as / or /var/run, or an exception occurs. Mount the volume to an empty directory. If the directory is not empty, ensure that there are no files that affect container startup. Otherwise, the files will be replaced, leading to container startup failures or workload creation failures. If a volume is mounted to a high-risk directory, use an account with minimum permissions to start the container. Otherwise, high-risk files on the host machine may be damaged. AOM collects only the first 20 logs that have been modified recently. It collects logs from 2 levels of subdirectories by default. AOM only collects text log files in .log, .trace, and .out formats in the mount paths. For details about how to set permissions for mount points in a container, see Configure a Security Context for a Pod or Container.
   Extended Host Path	This parameter is mandatory only if Volume Type is set to hostPath. Extended host paths contain pod IDs or container names to distinguish different containers into which the host path is mounted. A level-3 directory is added to the original volume directory/subdirectory. You can easily obtain the files output by a single Pod. None: No extended path is configured. PodUID: ID of a pod. PodName: name of a pod. PodUID/ContainerName: ID of a pod or name of a container. PodName/ContainerName: name of a pod or container.
   Collection Path	A collection path narrows down the scope of collection to specified logs. If no collection path is specified, log files in .log, .trace, and .out formats will be collected from the current path. Entering ** indicates that all log files in .log, .trace, and .out formats will be recursively collected from the specified path and all subdirectories of five levels deep. Entering * indicates fuzzy matching. Example: The collection path /tmp/**/test*.log indicates that all .log files prefixed with test will be collected from /tmp and subdirectories of five levels deep. CAUTION: Ensure that the version of ICAgent is 5.12.22 or later.
   Log Dump	Log dump refers to rotating log files on a local host. Enable: AOM scans log files every minute. When a log file exceeds 50 MB, it is dumped immediately. A new .zip file is generated in the directory where the log file resides. For a log file, AOM stores only the latest 20 .zip files. When the number of .zip files exceeds 20, earlier .zip files will be deleted. Disable: AOM does not dump log files. NOTE: AOM rotates log files using copytruncate. Before enabling log dumping, ensure that log files are written in the append mode. Otherwise, file holes may occur. Currently, mainstream log components such as Log4j and Logback support log file rotation. If you have already set rotation for log files, skip the configuration. Otherwise, conflicts may occur. You are advised to configure log file rotation for your own services to flexibly control the size and number of rolled files.

4. Click OK.

Example YAML

apiVersion: apps/v1
kind: Deployment
metadata:
  name: testlog
  namespace: default
spec:
  selector:
    matchLabels:
      app: testlog
  template:
    replicas: 1
    metadata:
      labels:
        app: testlog
    spec:
      containers:
        - image: 'nginx:alpine'
          name: container-0
          resources:
            requests:
              cpu: 250m
              memory: 512Mi
            limits:
              cpu: 250m
              memory: 512Mi
          volumeMounts:
            - name: vol-log
              mountPath: /var/log/nginx
              policy:
                logs:
                  rotate: ''
      volumes:
        - emptyDir: {}
          name: vol-log
      imagePullSecrets:
        - name: default-secret

apiVersion: apps/v1
kind: Deployment
metadata:
  name: testlog
  namespace: default
spec:
  replicas: 1
  selector:
    matchLabels:
      app: testlog
  template:
    metadata:
      labels:
        app: testlog
    spec:
      containers:
        - image: 'nginx:alpine'
          name: container-0
          resources:
            requests:
              cpu: 250m
              memory: 512Mi
            limits:
              cpu: 250m
              memory: 512Mi
          volumeMounts:
            - name: vol-log
              mountPath: /var/log/nginx
              readOnly: false
              extendPathMode: PodUID
              policy:
                logs:
                  rotate: Hourly
                  annotations:
                    pathPattern: '**'
                    
      volumes:
        - hostPath:
            path: /tmp/log
          name: vol-log
      imagePullSecrets:
        - name: default-secret

Viewing Logs

• View the logs of a specified pod.

  kubectl logs <pod_name> -n <namespace>
  
  

• View the logs of a specified pod in real time.

  kubectl logs -f <pod_name> -n <namespace>
  
  

• View the logs of a specified container in a specified pod.

  kubectl logs <pod_name> -c <container_name> -n <namespace>
  
  

• View the logs of a specified container in a specified pod in real time.

  kubectl logs -f <pod_name> -c <container_name> -n <namespace>