Bug Reporting Guidelines

When you find a bug in Munin we want to hear about it. Your bug reports play an important part in making Munin more reliable because even the utmost care cannot guarantee that every part of Munin will work on every platform under every circumstance.

The following suggestions are intended to assist you in forming bug reports that can be handled in an effective fashion. No one is required to follow them but doing so tends to be to everyone’s advantage.

We cannot promise to fix every bug right away. If the bug is obvious, critical, or affects a lot of users, chances are good that someone will look into it. It could also happen that we tell you to update to a newer version to see if the bug happens there. Or we might decide that the bug cannot be fixed before some major rewrite we might be planning is done. Or perhaps it is simply too hard and there are more important things on the agenda. If you need help immediately, consider obtaining a commercial support contract.

Identifying Bugs

Before you report a bug, please read and re-read the documentation to verify that you can really do whatever it is you are trying. If it is not clear from the documentation whether you can do something or not, please report that too; it is a bug in the documentation. If it turns out that a program does something different from what the documentation says, that is a bug. That might include, but is not limited to, the following circumstances:

  • A program terminates with a fatal signal or an operating system error message that would point to a problem in the program. (A counterexample might be a “disk full” message, since you have to fix that yourself.)
  • A program produces the wrong output for any given input.
  • A program refuses to accept valid input (as defined in the documentation).
  • A program accepts invalid input without a notice or error message. But keep in mind that your idea of invalid input might be our idea of an extension or compatibility with traditional practice.
  • Munin fails to compile, build, or install according to the instructions on supported platforms.

Here “program” refers to any executable, not only the back-end process.

Being slow or resource-hogging is not necessarily a bug. Read the documentation or ask on one of the mailing lists for help in tuning your applications.

Before you continue, check on the TODO list and in the FAQ to see if your bug is already known. If you cannot decode the information on the TODO list, report your problem. The least we can do is make the TODO list clearer.

What to Report

The most important thing to remember about bug reporting is to state all the facts and only facts. Do not speculate what you think went wrong, what “it seemed to do”, or which part of the program has a fault. If you are not familiar with the implementation you would probably guess wrong and not help us a bit. And even if you are, educated explanations are a great supplement to but no substitute for facts. If we are going to fix the bug we still have to see it happen for ourselves first. Reporting the bare facts is relatively straightforward (you can probably copy and paste them from the screen) but all too often important details are left out because someone thought it does not matter or the report would be understood anyway.

The following items should be contained in every bug report:

  • The exact sequence of steps from program start-up necessary to reproduce the problem. This should be self-contained; it is not enough to send in a bare log output without the plugin config and fetch statements.
  • The best format for a test case for a restitution issue (graphing or HTML) is a sample plugin that can be run through a single munin install that shows the problem. (Be sure to not depend on anything outside your sample plugin). You are encouraged to minimize the size of your example, but this is not absolutely necessary. If the bug is reproducible, we will find it either way.
  • The output you got. Please do not say that it “didn’t work” or “crashed”. If there is an error message, show it, even if you do not understand it. If the program terminates with an operating system error, say which. If nothing at all happens, say so. Even if the result of your test case is a program crash or otherwise obvious it might not happen on our platform. The easiest thing is to copy the output from the terminal, if possible.


If you are reporting an error message, please obtain the most verbose form of the message. Use the –debug command line arg.

  • The output you expected is very important to state. If you just write “This command gives me that output.” or “This is not what I expected.”, we might run it ourselves, scan the output, and think it looks OK and is exactly what we expected. We should not have to spend the time to decode the exact semantics behind your commands. Especially refrain from merely saying that “This is not what Cacti/Collectd/... does.”
  • Any command line options and other start-up options, including any relevant environment variables or configuration files that you changed from the default. Again, please provide exact information. If you are using a prepackaged distribution that starts the database server at boot time, you should try to find out how that is done.
  • Anything you did at all differently from the installation instructions.
  • The Munin version. If you run a prepackaged version, such as RPMs, say so, including any subversion the package might have. If you are talking about a Git snapshot, mention that, including the commit hash.
  • If your version is older than 2.0.x we will almost certainly tell you to upgrade. There are many bug fixes and improvements in each new release, so it is quite possible that a bug you have encountered in an older release of Munin has already been fixed. We can only provide limited support for sites using older releases of Munin; if you require more than we can provide, consider acquiring a commercial support contract.
  • Platform information. This includes the kernel name and version, perl version, processor, memory information, and so on. In most cases it is sufficient to report the vendor and version, but do not assume everyone knows what exactly “Debian” contains or that everyone runs on amd64.

Where to Report

In general fill in the bug report web-form available at the project’s GitHub.

If your bug report has security implications and you’d prefer that it not become immediately visible in public archives, don’t send it to bugs. Security issues can be reported privately to <security@munin-monitoring.org>.

Do not send bug reports to any of the user mailing lists. These mailing lists are for answering user questions, and their subscribers normally do not wish to receive bug reports. More importantly, they are unlikely to fix them. If you have some doubts about your issue being a bug, just drop by on IRC and ask there first.

If you have a problem with the documentation, the best place to report it is on IRC where most of the devs hang out. Please be specific about what part of the documentation you are unhappy with.


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