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Diffstat (limited to 'nixpkgs/nixos/modules/services/monitoring/prometheus/exporters.xml')
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diff --git a/nixpkgs/nixos/modules/services/monitoring/prometheus/exporters.xml b/nixpkgs/nixos/modules/services/monitoring/prometheus/exporters.xml new file mode 100644 index 000000000000..7a0a1bdf2c14 --- /dev/null +++ b/nixpkgs/nixos/modules/services/monitoring/prometheus/exporters.xml @@ -0,0 +1,187 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="module-services-prometheus-exporters"> + <title>Prometheus exporters</title> + <para> + Prometheus exporters provide metrics for the + <link xlink:href="https://prometheus.io">prometheus monitoring system</link>. + </para> + <section xml:id="module-services-prometheus-exporters-configuration"> + <title>Configuration</title> + + <para> + One of the most common exporters is the + <link xlink:href="https://github.com/prometheus/node_exporter">node + exporter</link>, it provides hardware and OS metrics from the host it's + running on. The exporter could be configured as follows: +<programlisting> + services.promtheus.exporters.node = { + enable = true; + enabledCollectors = [ + "logind" + "systemd" + ]; + disabledCollectors = [ + "textfile" + ]; + openFirewall = true; + firewallFilter = "-i br0 -p tcp -m tcp --dport 9100"; + }; +</programlisting> + It should now serve all metrics from the collectors that are explicitly + enabled and the ones that are + <link xlink:href="https://github.com/prometheus/node_exporter#enabled-by-default">enabled + by default</link>, via http under <literal>/metrics</literal>. In this + example the firewall should just allow incoming connections to the + exporter's port on the bridge interface <literal>br0</literal> (this would + have to be configured seperately of course). For more information about + configuration see <literal>man configuration.nix</literal> or search through + the + <link xlink:href="https://nixos.org/nixos/options.html#prometheus.exporters">available + options</link>. + </para> + </section> + <section xml:id="module-services-prometheus-exporters-new-exporter"> + <title>Adding a new exporter</title> + + <para> + To add a new exporter, it has to be packaged first (see + <literal>nixpkgs/pkgs/servers/monitoring/prometheus/</literal> for + examples), then a module can be added. The postfix exporter is used in this + example: + </para> + + <itemizedlist> + <listitem> + <para> + Some default options for all exporters are provided by + <literal>nixpkgs/nixos/modules/services/monitoring/prometheus/exporters.nix</literal>: + </para> + </listitem> + <listitem override='none'> + <itemizedlist> + <listitem> + <para> + <literal>enable</literal> + </para> + </listitem> + <listitem> + <para> + <literal>port</literal> + </para> + </listitem> + <listitem> + <para> + <literal>listenAddress</literal> + </para> + </listitem> + <listitem> + <para> + <literal>extraFlags</literal> + </para> + </listitem> + <listitem> + <para> + <literal>openFirewall</literal> + </para> + </listitem> + <listitem> + <para> + <literal>firewallFilter</literal> + </para> + </listitem> + <listitem> + <para> + <literal>user</literal> + </para> + </listitem> + <listitem> + <para> + <literal>group</literal> + </para> + </listitem> + </itemizedlist> + </listitem> + <listitem> + <para> + As there is already a package available, the module can now be added. This + is accomplished by adding a new file to the + <literal>nixos/modules/services/monitoring/prometheus/exporters/</literal> + directory, which will be called postfix.nix and contains all exporter + specific options and configuration: +<programlisting> + # nixpgs/nixos/modules/services/prometheus/exporters/postfix.nix + { config, lib, pkgs }: + + with lib; + + let + # for convenience we define cfg here + cfg = config.services.prometheus.exporters.postfix; + in + { + port = 9154; # The postfix exporter listens on this port by default + + # `extraOpts` is an attribute set which contains additional options + # (and optional overrides for default options). + # Note that this attribute is optional. + extraOpts = { + telemetryPath = mkOption { + type = types.str; + default = "/metrics"; + description = '' + Path under which to expose metrics. + ''; + }; + logfilePath = mkOption { + type = types.path; + default = /var/log/postfix_exporter_input.log; + example = /var/log/mail.log; + description = '' + Path where Postfix writes log entries. + This file will be truncated by this exporter! + ''; + }; + showqPath = mkOption { + type = types.path; + default = /var/spool/postfix/public/showq; + example = /var/lib/postfix/queue/public/showq; + description = '' + Path at which Postfix places its showq socket. + ''; + }; + }; + + # `serviceOpts` is an attribute set which contains configuration + # for the exporter's systemd service. One of + # `serviceOpts.script` and `serviceOpts.serviceConfig.ExecStart` + # has to be specified here. This will be merged with the default + # service confiuration. + serviceOpts = { + serviceConfig = { + ExecStart = '' + ${pkgs.prometheus-postfix-exporter}/bin/postfix_exporter \ + --web.listen-address ${cfg.listenAddress}:${toString cfg.port} \ + --web.telemetry-path ${cfg.telemetryPath} \ + ${concatStringsSep " \\\n " cfg.extraFlags} + ''; + }; + }; + } + </programlisting> + </para> + </listitem> + <listitem> + <para> + This should already be enough for the postfix exporter. Additionally one + could now add assertions and conditional default values. This can be done + in the 'meta-module' that combines all exporter definitions and generates + the submodules: + <literal>nixpkgs/nixos/modules/services/prometheus/exporters.nix</literal> + </para> + </listitem> + </itemizedlist> + </section> +</chapter> |