Logging

CloudNativePG outputs logs in JSON format directly to standard output, including PostgreSQL logs, without persisting them to storage for security reasons. This design facilitates seamless integration with most Kubernetes-compatible log management tools, including command line ones like stern.

Each log entry includes the following fields:

• level – The log level (e.g., info, notice).
• ts – The timestamp.
• logger – The type of log (e.g., postgres, pg_controldata).
• msg – The log message, or the keyword record if the message is in JSON format.
• record – The actual record, with a structure that varies depending on the logger type.
• logging_pod – The name of the pod where the log was generated.

Cluster Logs

You can configure the log level for the instance pods in the cluster specification using the logLevel option. Available log levels are: error, warning, info (default), debug, and trace.

Currently, the log level can only be set at the time the instance starts. Changes to the log level in the cluster specification after the cluster has started will only apply to new pods, not existing ones.

Operator Logs

The logs produced by the operator pod can be configured with log levels, same as instance pods: error, warning, info (default), debug, and trace.

The log level for the operator can be configured by editing the Deployment definition of the operator and setting the --log-level command line argument to the desired value.

PostgreSQL Logs

Each PostgreSQL log entry is a JSON object with the logger key set to postgres. The structure of the log entries is as follows:

{
  "level": "info",
  "ts": 1619781249.7188137,
  "logger": "postgres",
  "msg": "record",
  "record": {
    "log_time": "2021-04-30 11:14:09.718 UTC",
    "user_name": "",
    "database_name": "",
    "process_id": "25",
    "connection_from": "",
    "session_id": "608be681.19",
    "session_line_num": "1",
    "command_tag": "",
    "session_start_time": "2021-04-30 11:14:09 UTC",
    "virtual_transaction_id": "",
    "transaction_id": "0",
    "error_severity": "LOG",
    "sql_state_code": "00000",
    "message": "database system was interrupted; last known up at 2021-04-30 11:14:07 UTC",
    "detail": "",
    "hint": "",
    "internal_query": "",
    "internal_query_pos": "",
    "context": "",
    "query": "",
    "query_pos": "",
    "location": "",
    "application_name": "",
    "backend_type": "startup"
  },
  "logging_pod": "cluster-example-1",
}

PGAudit Logs

CloudNativePG offers seamless and native support for PGAudit on PostgreSQL clusters.

To enable PGAudit, add the necessary pgaudit parameters in the postgresql section of the cluster configuration.

Additionally, the operator manages the creation and removal of the PGAudit extension across all databases within the cluster.

The following example demonstrates a PostgreSQL Cluster deployment with PGAudit enabled and configured:

apiVersion: postgresql.cnpg.io/v1
kind: Cluster
metadata:
  name: cluster-example
spec:
  instances: 3

  postgresql:
    parameters:
      "pgaudit.log": "all, -misc"
      "pgaudit.log_catalog": "off"
      "pgaudit.log_parameter": "on"
      "pgaudit.log_relation": "on"

  storage:
    size: 1Gi

The audit CSV log entries generated by PGAudit are parsed and routed to standard output in JSON format, similar to all other logs:

• .logger is set to pgaudit.
• .msg is set to record.
• .record contains the entire parsed record as a JSON object. This structure resembles that of logging_collector logs, with the exception of .record.audit, which contains the PGAudit CSV message formatted as a JSON object.

This example shows sample log entries:

{
  "level": "info",
  "ts": 1627394507.8814096,
  "logger": "pgaudit",
  "msg": "record",
  "record": {
    "log_time": "2021-07-27 14:01:47.881 UTC",
    "user_name": "postgres",
    "database_name": "postgres",
    "process_id": "203",
    "connection_from": "[local]",
    "session_id": "610011cb.cb",
    "session_line_num": "1",
    "command_tag": "SELECT",
    "session_start_time": "2021-07-27 14:01:47 UTC",
    "virtual_transaction_id": "3/336",
    "transaction_id": "0",
    "error_severity": "LOG",
    "sql_state_code": "00000",
    "backend_type": "client backend",
    "audit": {
      "audit_type": "SESSION",
      "statement_id": "1",
      "substatement_id": "1",
      "class": "READ",
      "command": "SELECT FOR KEY SHARE",
      "statement": "SELECT pg_current_wal_lsn()",
      "parameter": "<none>"
    }
  },
  "logging_pod": "cluster-example-1",
}

See the PGAudit documentation for more details about each field in a record.

Other Logs

All logs generated by the operator and its instances are in JSON format, with the logger field indicating the process that produced them. The possible logger values are as follows:

• barman-cloud-wal-archive: logs from barman-cloud-wal-archive
• barman-cloud-wal-restore: logs from barman-cloud-wal-restore
• initdb: logs from running initdb
• pg_basebackup: logs from running pg_basebackup
• pg_controldata: logs from running pg_controldata
• pg_ctl: logs from running any pg_ctl subcommand
• pg_rewind: logs from running pg_rewind
• pgaudit: logs from the PGAudit extension
• postgres: logs from the postgres instance (with msg distinct from record)
• wal-archive: logs from the wal-archive subcommand of the instance manager
• wal-restore: logs from the wal-restore subcommand of the instance manager
• instance-manager: from the PostgreSQL instance manager

With the exception of postgres, which follows a specific structure, all other logger values contain the msg field with the escaped message that is logged.