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Junos Logger Utility

Use the Junos logger utility to record custom system log messages or generate event notifications for validating event policies in a test environment.

The Junos software includes a logger utility, which enables you to:

  • Record custom messages in the system log file

  • Simulate Junos event notifications

Junos Logger Overview

The Junos logger is a shell utility that you can use to log custom messages to the system log file and artificially generate event notifications. The logger enables you to successfully test event policies and event scripts even when the trigger event is difficult to reproduce.

You can configure event policies on Junos devices to execute specific actions in response to an event or series of events. It is important to test an event policy before deploying it in a production environment to ensure that the policy triggers as expected and performs the correct actions. In some cases, it is difficult to simulate the environment that generates the events required to trigger an event policy. In these cases, you can use the Junos logger utility to generate event notifications to trigger the policy.

Note:

The Junos event logger is an unsupported shell utility that should not be used on devices in a production environment. However, the utility is well suited for use in lab environments where you are developing and verifying event policies and event scripts.

The logger utility also enables you to record a message in the system log without triggering an event notification. Thus, you can log supplementary information about the system in addition to the messages and events that are automatically logged during normal device operations.

When you use the logger utility to generate event notifications or record custom log messages, the device uses a modified version of the base OS's logger utility. The modified utility accepts a specialized set of options that are designed for use with the Junos software.

Junos Logger Syntax (Generate an Event)

Syntax (Junos OS)

Syntax (Junos OS Evolved)

Description

Generate an event notification and also log the event in the system log, provided that the device is configured to log events with the specified priority.

Options

Table 1 outlines the required and optional arguments for the Junos event logger utility.

Table 1: Logger Options (Generate an Event)
Option Description Example

-a attribute=value

(Optional) Attribute associated with the event. The attribute name must be lowercase. To specify multiple attributes, include the -a option for each attribute.

For more information about the attributes associated with a particular Junos event, view the event's details in the System Log Explorer tool.

-a username=admin
-a command=commit

-d process

(Optional) Junos process (daemon) to use as the event's source process.

If you do not specify a process, Junos OS uses logger for the process, and Junos OS Evolved uses EVENTD_LOGGER for the process.

-d mgd

-e EVENT_ID

Event for which to generate the event notification. The event identifier must be uppercase.

-e UI_COMMIT

-l logical-system-name

(Optional) Generate and log an event notification in the log file for the specified logical system.

-l ls-router1

-p priority

(Optional) Log the event with the given priority, specified numerically or as a syslog facility.severity pair.

The default priority is user.notice.

-p external.notice
message

(Optional) Message string to record in the system log. Quotes are not required, but they are recommended for clarity.

 "This is a manually generated test event."

Junos Logger Syntax (Log a Message)

Syntax (Junos OS)

Syntax (Junos OS Evolved)

Description

Log entries in the system log, provided that the device is configured to log messages with the specified priority.

Note:

On devices running Junos OS Evolved, you can also use the Linux logger utility in the system shell to record messages in the system log.

Options

When you use the Junos logger utility to record custom messages in the system log, the device calls the logger utility for the underlying base OS. Only a subset of the logger options are supported on Junos devices. Table 2 outlines the supported options.

Table 2: Logger Options (Log a Message)
Option           Description

(-4 | -6)

(Optional) On Junos OS, use IPv4 or IPv6 addresses only.

-A

(Optional) On Junos OS, attempt to send the message to all addresses.

-f file

(Optional) Copy the contents of the specified file into the system log file.

-h host

(Optional) On Junos OS, send the message to the specified remote host instead of logging it locally.

-i

(Optional) Log the process ID of the logger process with each line.

-p priority

(Optional) Generate the event with the given priority, specified numerically or as a syslog facility.severity pair.

The default priority is user.notice.

-s

(Optional) Log the message to standard error, in addition to the system log file.

-t tag

(Optional) Log the entry with the specified tag instead of the default tag, which is the current username.
message

(Optional) Message string to record in the system log. Quotes are not required, but they are recommended for clarity.

Use the Junos Logger to Generate Events

The Junos event logger is a shell utility. To use the utility, you must first start a system shell.

To generate an event notification and also log it in the system log file:

  1. Start a system shell.

    The shell prompt varies depending on the OS and whether the user is the root user. For example:

    • In Junos OS:

    • In Junos OS Evolved:

  2. Generate an event by calling the Junos logger utility and specifying the event ID in uppercase as well as any other optional arguments.

    For example, the following commands simulate a UI_COMMIT event. The event is generated by the mgd process and has event priority external.notice.

    • In Junos OS:

    • In Junos OS Evolved:

The event notification is sent to the eventd process. The device also records the event information and specified message in the system log file, provided you have configured the device to log messages of the given facility and severity level.

You can use the Junos event logger utility to generate one or more event notifications to trigger and test an event policy when it is difficult to reproduce the events in a given lab environment. In the previous example, the device will execute any policies that trigger on the UI_COMMIT event.

Use the Junos Logger to Log Messages

The Junos logger is a shell utility. To use the utility, you must first start a system shell.

To log information in the system log file:

  1. Start a system shell.

    The shell prompt varies depending on the OS and whether the user is the root user. For example:

    • In Junos OS:

    • In Junos OS Evolved:

  2. Log a message to the system log by calling the Junos logger utility and specifying the information to log as well as any optional arguments.

    For example, the following commands log the given message string with the CUSTOM_LOG tag and a priority of external.notice.

    • In Junos OS:

    • In Junos OS Evolved:

In this example, the message string is recorded in the system log with the CUSTOM_LOG tag, provided you have configured the device to log messages of the given facility and severity level.