container_logs.md

Log types

Lobster supports k8s stdout/stderr and File log(emptydir) collection.

• k8s stdout/stderr: Logs from processes associated with stdout and stderr are automatically collected without any additional settings
• File log(emptydir): Logs are collected from Kubernetes emptyDir volumes when specific conditions are met

In Lobster web page, you can view this information under the Sources field

Kubernetes logs, stdout/stderr

• In the Kubernetes environment, the container's stdout/stderr logs are recorded on Node’s disk
• The stdout/stderr logs are automatically collected by the logging system installed on Node
• The log line format is as follows:
  • {RFC 3339Nano timestamp} {stdout/stderr} {Partial/Full} {log}
  • https://github.com/kubernetes/design-proposals-archive/blob/main/node/kubelet-cri-logging.md

File log (emptyDir)

• If you mount an emptyDir volume in a container, you can store a log file on the Node's disk The files that meet the following requirements for collection are automatically tracked and collected
• Multiple log files created in a single container can be collected and retrieved
• The log line format is as follows:
  • {RFC 3339 Nano timestamp} {log}
• Requirements for collection
  • timestamp
    • The log line must start with {RFC 3339 Nano timestamp}
    • Logs are collected and retrieved based on the timestamp located in the log line head, even if there is a separate timestamp in the log
  • .log file extension
    • If logs are stored in a Kubernetes emptyDir, the logging system tracks logs recorded in the Node's disk
    • Only files with the .log extension on the Node disk can be tracked