nixpkgs/nixos/modules/services/monitoring/munin.nix
Ben Kelly ace4855cf6 nixos/munin: enable munin_update and disable munin_stats
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.)
2019-02-04 20:17:26 -05:00

405 lines
13 KiB
Nix

{ config, lib, pkgs, ... }:
# TODO: support munin-async
# TODO: LWP/Pg perl libs aren't recognized
# TODO: support fastcgi
# http://guide.munin-monitoring.org/en/latest/example/webserver/apache-cgi.html
# spawn-fcgi -s /run/munin/fastcgi-graph.sock -U www-data -u munin -g munin /usr/lib/munin/cgi/munin-cgi-graph
# spawn-fcgi -s /run/munin/fastcgi-html.sock -U www-data -u munin -g munin /usr/lib/munin/cgi/munin-cgi-html
# https://paste.sh/vofcctHP#-KbDSXVeWoifYncZmLfZzgum
# nginx http://munin.readthedocs.org/en/latest/example/webserver/nginx.html
with lib;
let
nodeCfg = config.services.munin-node;
cronCfg = config.services.munin-cron;
muninConf = pkgs.writeText "munin.conf"
''
dbdir /var/lib/munin
htmldir /var/www/munin
logdir /var/log/munin
rundir /run/munin
${lib.optionalString (cronCfg.extraCSS != "") "staticdir ${customStaticDir}"}
${cronCfg.extraGlobalConfig}
${cronCfg.hosts}
'';
nodeConf = pkgs.writeText "munin-node.conf"
''
log_level 3
log_file Sys::Syslog
port 4949
host *
background 0
user root
group root
host_name ${config.networking.hostName}
setsid 0
# wrapped plugins by makeWrapper being with dots
ignore_file ^\.
allow ^::1$
allow ^127\.0\.0\.1$
${nodeCfg.extraConfig}
'';
pluginConf = pkgs.writeText "munin-plugin-conf"
''
[hddtemp_smartctl]
user root
group root
[meminfo]
user root
group root
[ipmi*]
user root
group root
[munin*]
env.UPDATE_STATSFILE /var/lib/munin/munin-update.stats
${nodeCfg.extraPluginConfig}
'';
pluginConfDir = pkgs.stdenv.mkDerivation {
name = "munin-plugin-conf.d";
buildCommand = ''
mkdir $out
ln -s ${pluginConf} $out/nixos-config
'';
};
# Copy one Munin plugin into the Nix store with a specific name.
# This is suitable for use with plugins going directly into /etc/munin/plugins,
# i.e. munin.extraPlugins.
internOnePlugin = name: path:
"cp -a '${path}' '${name}'";
# Copy an entire tree of Munin plugins into a single directory in the Nix
# store, with no renaming.
# This is suitable for use with munin-node-configure --suggest, i.e.
# munin.extraAutoPlugins.
internManyPlugins = name: path:
"find '${path}' -type f -perm /a+x -exec cp -a -t . '{}' '+'";
# Use the appropriate intern-fn to copy the plugins into the store and patch
# them afterwards in an attempt to get them to run on NixOS.
internAndFixPlugins = name: intern-fn: paths:
pkgs.runCommand name {} ''
mkdir -p "$out"
cd "$out"
${lib.concatStringsSep "\n"
(lib.attrsets.mapAttrsToList intern-fn paths)}
chmod -R u+w .
find . -type f -exec sed -E -i '
s,(/usr)?/s?bin/,/run/current-system/sw/bin/,g
' '{}' '+'
'';
# TODO: write a derivation for munin-contrib, so that for contrib plugins
# you can just refer to them by name rather than needing to include a copy
# of munin-contrib in your nixos configuration.
extraPluginDir = internAndFixPlugins "munin-extra-plugins.d"
internOnePlugin nodeCfg.extraPlugins;
extraAutoPluginDir = internAndFixPlugins "munin-extra-auto-plugins.d"
internManyPlugins
(builtins.listToAttrs
(map
(path: { name = baseNameOf path; value = path; })
nodeCfg.extraAutoPlugins));
customStaticDir = pkgs.runCommand "munin-custom-static-data" {} ''
cp -a "${pkgs.munin}/etc/opt/munin/static" "$out"
cd "$out"
chmod -R u+w .
echo "${cronCfg.extraCSS}" >> style.css
echo "${cronCfg.extraCSS}" >> style-new.css
'';
in
{
options = {
services.munin-node = {
enable = mkOption {
default = false;
type = types.bool;
description = ''
Enable Munin Node agent. Munin node listens on 0.0.0.0 and
by default accepts connections only from 127.0.0.1 for security reasons.
See <link xlink:href='http://guide.munin-monitoring.org/en/latest/architecture/index.html' />.
'';
};
extraConfig = mkOption {
default = "";
type = types.lines;
description = ''
<filename>munin-node.conf</filename> extra configuration. See
<link xlink:href='http://guide.munin-monitoring.org/en/latest/reference/munin-node.conf.html' />
'';
};
extraPluginConfig = mkOption {
default = "";
type = types.lines;
description = ''
<filename>plugin-conf.d</filename> extra plugin configuration. See
<link xlink:href='http://guide.munin-monitoring.org/en/latest/plugin/use.html' />
'';
example = ''
[fail2ban_*]
user root
'';
};
extraPlugins = mkOption {
default = {};
type = with types; attrsOf path;
description = ''
Additional Munin plugins to activate. Keys are the name of the plugin
symlink, values are the path to the underlying plugin script. You
can use the same plugin script multiple times (e.g. for wildcard
plugins).
Note that these plugins do not participate in autoconfiguration. If
you want to autoconfigure additional plugins, use
<option>services.munin-node.extraAutoPlugins</option>.
Plugins enabled in this manner take precedence over autoconfigured
plugins.
Plugins will be copied into the Nix store, and it will attempt to
modify them to run properly by fixing hardcoded references to
<literal>/bin</literal>, <literal>/usr/bin</literal>,
<literal>/sbin</literal>, and <literal>/usr/sbin</literal>.
'';
example = literalExample ''
{
zfs_usage_bigpool = /src/munin-contrib/plugins/zfs/zfs_usage_;
zfs_usage_smallpool = /src/munin-contrib/plugins/zfs/zfs_usage_;
zfs_list = /src/munin-contrib/plugins/zfs/zfs_list;
};
'';
};
extraAutoPlugins = mkOption {
default = [];
type = with types; listOf path;
description = ''
Additional Munin plugins to autoconfigure, using
<literal>munin-node-configure --suggest</literal>. These should be
the actual paths to the plugin files (or directories containing them),
not just their names.
If you want to manually enable individual plugins instead, use
<option>services.munin-node.extraPlugins</option>.
Note that only plugins that have the 'autoconfig' capability will do
anything if listed here, since plugins that cannot autoconfigure
won't be automatically enabled by
<literal>munin-node-configure</literal>.
Plugins will be copied into the Nix store, and it will attempt to
modify them to run properly by fixing hardcoded references to
<literal>/bin</literal>, <literal>/usr/bin</literal>,
<literal>/sbin</literal>, and <literal>/usr/sbin</literal>.
'';
example = literalExample ''
[
/src/munin-contrib/plugins/zfs
/src/munin-contrib/plugins/ssh
];
'';
};
disabledPlugins = mkOption {
# TODO: figure out why Munin isn't writing the log file and fix it.
# In the meantime this at least suppresses a useless graph full of
# NaNs in the output.
default = [ "munin_stats" ];
type = with types; listOf string;
description = ''
Munin plugins to disable, even if
<literal>munin-node-configure --suggest</literal> tries to enable
them. To disable a wildcard plugin, use an actual wildcard, as in
the example.
munin_stats is disabled by default as it tries to read
<literal>/var/log/munin/munin-update.log</literal> for timing
information, and the NixOS build of Munin does not write this file.
'';
example = [ "diskstats" "zfs_usage_*" ];
};
};
services.munin-cron = {
enable = mkOption {
default = false;
type = types.bool;
description = ''
Enable munin-cron. Takes care of all heavy lifting to collect data from
nodes and draws graphs to html. Runs munin-update, munin-limits,
munin-graphs and munin-html in that order.
HTML output is in <filename>/var/www/munin/</filename>, configure your
favourite webserver to serve static files.
'';
};
extraGlobalConfig = mkOption {
default = "";
type = types.lines;
description = ''
<filename>munin.conf</filename> extra global configuration.
See <link xlink:href='http://guide.munin-monitoring.org/en/latest/reference/munin.conf.html' />.
Useful to setup notifications, see
<link xlink:href='http://guide.munin-monitoring.org/en/latest/tutorial/alert.html' />
'';
example = ''
contact.email.command mail -s "Munin notification for ''${var:host}" someone@example.com
'';
};
hosts = mkOption {
default = "";
type = types.lines;
description = ''
Definitions of hosts of nodes to collect data from. Needs at least one
host for cron to succeed. See
<link xlink:href='http://guide.munin-monitoring.org/en/latest/reference/munin.conf.html' />
'';
example = ''
[''${config.networking.hostName}]
address localhost
'';
};
extraCSS = mkOption {
default = "";
type = types.lines;
description = ''
Custom styling for the HTML that munin-cron generates. This will be
appended to the CSS files used by munin-cron and will thus take
precedence over the builtin styles.
'';
example = ''
/* A simple dark theme. */
html, body { background: #222222; }
#header, #footer { background: #333333; }
img.i, img.iwarn, img.icrit, img.iunkn {
filter: invert(100%) hue-rotate(-30deg);
}
'';
};
};
};
config = mkMerge [ (mkIf (nodeCfg.enable || cronCfg.enable) {
environment.systemPackages = [ pkgs.munin ];
users.users = [{
name = "munin";
description = "Munin monitoring user";
group = "munin";
uid = config.ids.uids.munin;
home = "/var/lib/munin";
}];
users.groups = [{
name = "munin";
gid = config.ids.gids.munin;
}];
}) (mkIf nodeCfg.enable {
systemd.services.munin-node = {
description = "Munin Node";
after = [ "network.target" ];
wantedBy = [ "multi-user.target" ];
path = with pkgs; [ munin smartmontools "/run/current-system/sw" "/run/wrappers" ];
environment.MUNIN_LIBDIR = "${pkgs.munin}/lib";
environment.MUNIN_PLUGSTATE = "/run/munin";
environment.MUNIN_LOGDIR = "/var/log/munin";
preStart = ''
echo "Updating munin plugins..."
mkdir -p /etc/munin/plugins
rm -rf /etc/munin/plugins/*
# Autoconfigure builtin plugins
${pkgs.munin}/bin/munin-node-configure --suggest --shell --families contrib,auto,manual --config ${nodeConf} --libdir=${pkgs.munin}/lib/plugins --servicedir=/etc/munin/plugins --sconfdir=${pluginConfDir} 2>/dev/null | ${pkgs.bash}/bin/bash
# Autoconfigure extra plugins
${pkgs.munin}/bin/munin-node-configure --suggest --shell --families contrib,auto,manual --config ${nodeConf} --libdir=${extraAutoPluginDir} --servicedir=/etc/munin/plugins --sconfdir=${pluginConfDir} 2>/dev/null | ${pkgs.bash}/bin/bash
${lib.optionalString (nodeCfg.extraPlugins != {}) ''
# Link in manually enabled plugins
ln -f -s -t /etc/munin/plugins ${extraPluginDir}/*
''}
${lib.optionalString (nodeCfg.disabledPlugins != []) ''
# Disable plugins
cd /etc/munin/plugins
rm -f ${toString nodeCfg.disabledPlugins}
''}
'';
serviceConfig = {
ExecStart = "${pkgs.munin}/sbin/munin-node --config ${nodeConf} --servicedir /etc/munin/plugins/ --sconfdir=${pluginConfDir}";
};
};
# munin_stats plugin breaks as of 2.0.33 when this doesn't exist
systemd.tmpfiles.rules = [ "d /run/munin 0755 munin munin -" ];
}) (mkIf cronCfg.enable {
# Munin is hardcoded to use DejaVu Mono and the graphs come out wrong if
# it's not available.
fonts.fonts = [ pkgs.dejavu_fonts ];
systemd.timers.munin-cron = {
description = "batch Munin master programs";
wantedBy = [ "timers.target" ];
timerConfig.OnCalendar = "*:0/5";
};
systemd.services.munin-cron = {
description = "batch Munin master programs";
unitConfig.Documentation = "man:munin-cron(8)";
serviceConfig = {
Type = "oneshot";
User = "munin";
ExecStart = "${pkgs.munin}/bin/munin-cron --config ${muninConf}";
};
};
systemd.tmpfiles.rules = [
"d /run/munin 0755 munin munin -"
"d /var/log/munin 0755 munin munin -"
"d /var/www/munin 0755 munin munin -"
"d /var/lib/munin 0755 munin munin -"
];
})];
}