Overview of Generating Custom Warning, Error, and System Log Messages
You can use a commit script to specify configuration rules that you always want to enforce. If a rule is broken, the commit script can emit a warning, error, or system log message.
In the Junos OS command-line interface (CLI), warning messages are emitted during commit operations to alert you that the configuration is not complete or contains a syntax error. If a custom configuration rule is broken, a custom warning message notifies you about the problem. The commit script causes the warning message to be passed back to the Junos OS CLI or to a Junos XML protocol client application. Unlike error messages, warning messages do not cause the commit operation to fail, so they are used for configuration problems that do not affect network traffic. A warning is best used as a response to configuration settings that do not adhere to recommended practices. An example of this type of configuration setting might be assignment of the same user ID to different users.
Alternatively, you can generate a custom warning message for a serious configuration problem, and specify an automatic configuration change that rectifies the problem. For more information about the use of warning messages in conjunction with automatic configuration changes, see Overview of Generating Persistent or Transient Configuration Changes Using Commit Scripts.
Unlike warning messages, a custom error message causes the commit operation to fail and notifies the user about the configuration problem. The commit script causes the error message to be passed back to the Junos OS CLI or to a Junos XML protocol client application. Because error messages cause the commit operation to fail, they are used for problems that affect network traffic. An error message is best used as a response to configuration settings that you want to disallow—for example, when required statements are omitted from the configuration.
Junos OS generates system log messages (also called syslog messages) to record events that occur on the device, including the following:
Routine operations, such as creation of an OSPF protocol adjacency or a user login into the configuration database
Failure and error conditions, such as failure to access a configuration file or unexpected closure of a connection to a child or peer process
Emergency or critical conditions, such as device power-down due to excessive temperature
Each system log message identifies the Junos OS process that generated the message and briefly describes the operation or error that occurred. The System Log Explorer provides more detailed information about system log messages.
With commit scripts, you can cause custom system log messages to be generated in response to particular events that you define. For example, if a configuration rule is broken, a custom message can be generated to record this occurrence. If the commit script corrects the configuration, a custom message can indicate that corrective action was taken.