Charon Log monitoring on Windows (logmond) - Best practices for V4.6 and V4.7

Charon Log monitoring on Windows (logmond) - Best practices for V4.6 and V4.7

Table of contents

Description

The Log Monitor & Dispatcher, known as LOGMOND, is a special program which monitors a guest LOG file produced by Charon and executes a customized script when it detects removal of a license. This utility is available for Charon-AXP and Charon-VAX V4.6 and above.

It runs in the background (as a program or as a service) and periodically scans a specified LOG file. When it detects a message with the code 0000002A or 00000351 ("Detected removal of a license"), it submits the nolicense.bat procedure (this BAT file must be created manually).

The Log Monitor & Dispatcher service is installed as EmulatorLogMonitor. By default it is installed in such a way that requires explicit actions to be started (either through a command line interface or using the standard ways of service management). For unattended execution, change the service’s configuration so that Windows starts the service automatically.

The tool requires a specific file "nolicense.bat" containing some specific instructions to be taken in situation of license absence. It is recommended you create this file in the folder (presumably) containing the LOG file.

When it is invoked by the “Log Monitor & Dispatcher”, the current directory of the batch process is set to the same folder from which the “Log Monitor & Dispatcher” was previously installed as a service or from which it was started as a background process. This means that the user action file may, in principle, operate with relative paths and relocate (as part of the whole configuration, i.e. together with accompanying LOG file).

The user action file will not invoke interactive applications as it may run in an environment where interactive services do not work, for example: when “Log Monitor & Dispatcher” is installed as a service.

The Log Monitor utility will report an alert only when no more license is available. It cannot send an alert when 2 dongles were connected (the main one and a backup one for example) and one is disconnected

 

Recommendations

  • Create a specific folder to hold the Charon configuration and log files, the nolicense.bat file and any specific action script you would add.

  • Use the rotating log files mechanism or use a single log file with "append" mode.

  • Install your virtual machines as services, they will then be able to start when the Charon Windows server will boot. This will also allows you to install and start the Charon log monitor service, named "EmulatorLogMonitor": doing so you will not have to start logmond manually in interactive mode and newly added virtual machines services will be automatically taken into account

If you're using rotating log files and you use the minus character ("-") in the configuration_name, the logmond process will not execute the nolicense.bat script file and will report a "wrong prefix" error (this can only be seen using the debugging mode)

Applies to: All Charon kits up to version 4.7 build 17101 (included)

A patch to replace logmond.exe file is available here.

Patch 17103, released on April 27th 2016, for Charon-AXP and Charon-VAX solves this problem.

Notes

  • The log monitor utility will detect the absence of the dongle only at a specified interval, called the license check interval and defined by the license. Its default is set to 1 hour. In case you need to perform tests, you can send us a fresh C2V file and ask for an update to reduce this interval.
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  • Once started the logmond utility will lock the virtual machine log file, you will not be able to move it, copy it or delete it. You will however be able to open it using the notepad utility or other log editors like baretail for example which will allow you to have a continuous view of the log with highlights (see: Charon Log files - Using baretail on Windows for syntax highlighting) or vim (see: Charon Log files - Using vim for syntax highlighting on Linux and Windows)
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  • If you encounter a "Can't open Charon log file" from the "Charon Service Manager" utility, please open the "Service Management" menu then select "Refresh Service List". This error occurs when the Service Manager has not detected a change in the configuration.

Service setup example

Example below is based on a Charon-AXP V4.7 B17101 running on a Windows 2012 R2 server and emulating an AlphaServer DS20. All files (configuration, bin, rom and nolicense.bat) are located in C:\Charon, rotating log files are located in C:\Charon\logs

The configuration file is defined as follows:

 

Setup and start your virtual machine

  • Run the Launcher, load the configuration file and click on the "Install / Update service" box:
    It is recommended to run the selected configuration from the Launcher at least once before installing the service to facilitate debugging
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  • Define the service name and click on the "Install" button:
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  • Start the Charon Service Manager, right click on the virtual machine, select "Manage Charon service" and start it:
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Install and start the log monitor service

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The nolicense.bat file must be placed in the virtual machine "Home directory". This directory corresponds to the configuration file folder when the service is installed, however it will not change if the configuration file is relocated and the service is updated. To locate this "Home directory" open the "Charon Service Manager" utility, right click on the corresponding service and select "View configuration"

Example:

 

The example below will append a line in a text file:.

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  • Install the log monitoring service and start it:

These command lines must be executed as an administrator in order to manage the services 


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  • Notes:

    • The EmulatorLogMonitor service running the logmond processes will discover already installed Charon virtual machines services. If a new virtual machine service is added, it's log file will be automatically discovered and monitored.

    • If you are running Charon-AXP/VAX/PDP version V4.8, the logmond.exe file is located by default in the "C:\Program Files\Charon\Build_18302\x64" folder
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  • Remove the dongle to check if the C:\Charon\logmond.log file is created:


During the tests the license check interval was set to 5 minutes therefore, when the dongle is disconnected, a message is sent telling there are only 4 minutes remaining before the DS20 stops
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Running the log monitor from the command line

The "logmond" utility has several parameters available. Use the "logmond -h" command to have a complete list.



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