munin_update relies on a stats file that exists, but isn't found in the
default location on NixOS; the appropriate plugin configuration is
added.
munin_stats relies on munin-cron writing a logfile, which the NixOS
build of munin does not. (This is probably fixable in the munin package,
but I don't have time to dig into that right now.)
This permits custom styling of the generated HTML without needing to
build your own Munin package from source. Also comes with an example
that works as a passable dark theme for Munin.
extraAutoPlugins lets you list plugins and plugin directories to be
autoconfigured, and extraPlugins lets you enable plugins on a one-by-one
basis. This can be used to enable plugins from contrib (although you'll
need to download and check out contrib yourself, then point these
options at it), or plugins you've written yourself.
munin-graph is hardcoded to use DejaVu Mono for the graph legends; if it
can't find it, there's no guarantee it finds a monospaced font at all,
and if it can't find a monospaced font the legends come out badly
misformatted.
This is just a set of globs to remove from the active plugins directory
after autoconfiguration is complete.
I also removed the hard-coded disabling of "diskstats", since it seems
to work just fine now.
Since this module was written, Munin has moved their documentation from
munin-monitoring.org/wiki to guide.munin-monitoring.org. Most of the
links were broken, and the ones that weren't went to "please use the new
site" pages.
as using /var/run now emits a warning by systemd's tmpfiles.d.
As /var/run is already a symlink to /run, this can't break anything, and
data does not need to be migrated.
The munin-node service used wrapProgram to inject environment variables.
This doesn't work because munin plugins depend on argv[0], which is
overwritten when the executable is a script with a shebang line (example
below).
This commit removes the wrappers and instead passes the required
environment variables to munin-node.
Eliminating the wrappers resulted in some broken plugins, e.g., meminfo
and hddtemp_smartctl. That was fixed with the per-plugin configuration.
Example:
The plugin if_eth0 is a symlink to /.../plugins/if_, which uses $0
to determine that it should monitor traffic on the eth0 interface.
if_ is a wrapped program, and runs `exec -a "$0" .if_-wrapped`
.if_-wrapped has a "#!/nix/.../bash" line, which results in bash
changing $0, and as a result the plugin thinks my interface
is called "-wrapped".
"Builder called die: Cannot wrap
/nix/store/XXX-munin-available-plugins/plugin.sh because it is not an
executable file"
[Bjørn: Keep DRY, quote "$file".]
- add missing types in module definitions
- add missing 'defaultText' in module definitions
- wrap example with 'literalExample' where necessary in module definitions
All activation scripts run in serial upon boot and nixos-rebuild switch
etc., in contrast to preStart which run before a service starts, and can
run in parallel with other services.
The munin(-node) activation script is particularly slow. Change it to a
preStart script so that it can run in parallel with other services and
not slow down boot (or nixos-rebuild switch).
This reduces (repeated) "nixos-rebuild test" time from ~16 seconds to ~8
on my (old) laptop.
Using pkgs.lib on the spine of module evaluation is problematic
because the pkgs argument depends on the result of module
evaluation. To prevent an infinite recursion, pkgs and some of the
modules are evaluated twice, which is inefficient. Using ‘with lib’
prevents this problem.
To be compatible with eb2f44c18c (Generate
/etc/passwd and /etc/group at build time). Without this you'll get this:
$ nixos-rebuild build
[...]
user-thrown exception: The option `users.extraGroups.unnamed-9.1.gid' is used but not defined.
(systemd service descriptions that is, not service descriptions in "man
configuration.nix".)
Capitalizing each word in the description seems to be the accepted
standard.
Also shorten these descriptions:
* "Munin node, the agent process" => "Munin Node"
* "Planet Venus, an awesome ‘river of news’ feed reader" => "Planet Venus Feed Reader"
