New enable_promethus_exporter parameter

Set `enable_promethus_exporter` to `true` to install and start a
Prometheus CvmFS Exporter published metrics from CvmFS mounts.

By default it will be listening on port 9868

Author: traylenator

REFERENCE.md

@@ -96,6 +96,17 @@ class{'cvmfs':
 }
 ```
 
+##### Enable Prometheus Metrics Exporter
+
+```puppet
+class{ 'cvmfs':
+  enable_prometheus_exporter => true,
+}
+class{ 'nftables::rules::node_exporter':
+  port => 9868,
+}
+```
+
 #### Parameters
 
 The following parameters are available in the `cvmfs` class:
@@ -159,6 +170,7 @@ The following parameters are available in the `cvmfs` class:
 * [`cvmfs_xattr_privileged_gids`](#-cvmfs--cvmfs_xattr_privileged_gids)
 * [`cvmfs_xattr_protected_xattrs`](#-cvmfs--cvmfs_xattr_protected_xattrs)
 * [`cvmfs_cache_refcount`](#-cvmfs--cvmfs_cache_refcount)
+* [`enable_prometheus_exporter`](#-cvmfs--enable_prometheus_exporter)
 * [`cvmfs_yum`](#-cvmfs--cvmfs_yum)
 * [`cvmfs_yum_priority`](#-cvmfs--cvmfs_yum_priority)
 * [`cvmfs_yum_proxy`](#-cvmfs--cvmfs_yum_proxy)
@@ -646,6 +658,14 @@ If set to yes, deduplicate open file descriptors by refcounting.
 
 Default value: `undef`
 
+##### <a name="-cvmfs--enable_prometheus_exporter"></a>`enable_prometheus_exporter`
+
+Data type: `Boolean`
+
+Install and start a Prometheus exporter on port 9868
+
+Default value: `false`
+
 ##### <a name="-cvmfs--cvmfs_yum"></a>`cvmfs_yum`
 
 Data type: `Optional[Stdlib::Httpurl]`

manifests/init.pp

@@ -45,6 +45,14 @@
 #    cvmfs_cache_refcount => 'yes',
 #  }
 #
+# @example Enable Prometheus Metrics Exporter
+#  class{ 'cvmfs':
+#    enable_prometheus_exporter => true,
+#  }
+#  class{ 'nftables::rules::node_exporter':
+#    port => 9868,
+#  }
+#
 # @param mount_method
 #    The `autofs` option will configure cvmfs to be mounted with autofs. The `mount` option will
 #    use puppet's mount type, currently adding a line to /etc/fstab. The *none* option
@@ -121,6 +129,7 @@
 # @param cvmfs_xattr_privileged_gids group IDs that are allowed to access the extended attributes by `$cvmfs_xattr_protected_xattrs`.
 # @param cvmfs_xattr_protected_xattrs List of extended attributes (full name, e.g. user.fqrn) that are only accessible by root and the group IDs listed by `$cvmfs_xattr_privileged_gids`.
 # @param cvmfs_cache_refcount If set to yes, deduplicate open file descriptors by refcounting.
+# @param enable_prometheus_exporter Install and start a Prometheus exporter on port 9868
 #
 # Deprecated paramters below
 # @param cvmfs_yum Deprecated, use repo_base
@@ -195,6 +204,7 @@
   Optional[Array[Integer[0],1]] $cvmfs_cpu_affinity                   = undef,
   Optional[Array[Integer[1],1]] $cvmfs_xattr_privileged_gids          = undef,
   Optional[Array[String[1],1]] $cvmfs_xattr_protected_xattrs          = undef,
+  Boolean $enable_prometheus_exporter                                 = false,
   # Deprecated Parameters
   Optional[Boolean] $cvmfs_yum_manage_repo                                = undef,
   Optional[Stdlib::Httpurl] $cvmfs_yum                                    = undef,

manifests/install.pp

@@ -5,6 +5,7 @@
   String[1] $cvmfs_version = $cvmfs::cvmfs_version,
   Stdlib::Absolutepath $cvmfs_cache_base = $cvmfs::cvmfs_cache_base,
   Optional[Enum['yes','no']] $cvmfs_claim_ownership = $cvmfs::cvmfs_claim_ownership,
+  Boolean $enable_prometheus_exporter = $cvmfs::enable_prometheus_exporter,
 ) inherits cvmfs {
   # Create the cache dir if one is defined, otherwise assume default is in the package.
   # Require the package so we know the user is in place.
@@ -36,4 +37,8 @@
     content => "---\n#This file generated by puppet and is used by custom facts only.\ncvmfs_cache_base: ${cvmfs_cache_base}\n",
     require => Package['cvmfs'],
   }
+
+  package { 'prometheus-cvmfs-exporter':
+    ensure => bool2str($enable_prometheus_exporter, 'installed','absent'),
+  }
 }

manifests/service.pp

@@ -4,6 +4,7 @@
 class cvmfs::service (
   Enum['autofs','mount','none'] $mount_method = $cvmfs::mount_method,
   Boolean $manage_autofs_service = $cvmfs::manage_autofs_service,
+  Boolean $enable_prometheus_exporter = $cvmfs::enable_prometheus_exporter,
 ) inherits cvmfs {
   # CVMFS 2.1 at least uses cvmfs_config.
 
@@ -19,4 +20,9 @@
       }
     )
   }
+
+  service { 'cvmfs-client-prometheus.socket':
+    ensure => $enable_prometheus_exporter,
+    enable => $enable_prometheus_exporter,
+  }
 }

spec/acceptance/cvmfs_prom_enable_spec.rb

@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+require 'spec_helper_acceptance'
+
+describe 'cvmfs enable_prometheus_exporter' do
+  it 'configures and work with no errors' do
+    # Clean up all existing mounts
+    shell('cvmfs_config killall', acceptable_exit_codes: [0, 127])
+    pp = <<-PUPPET
+         class{ 'cvmfs':
+           cvmfs_http_proxy           => 'http://ca-proxy.cern.ch:3128;DIRECT',
+           enable_prometheus_exporter => true,
+         }
+         cvmfs::domain{ 'cern.ch':
+          cvmfs_server_url =>  'http://cvmfs-stratum-one.cern.ch/cvmfs/@fqrn@'
+         }
+    PUPPET
+    # Run it three times, it should be stable by then
+    apply_manifest(pp, catch_failures: true)
+    apply_manifest(pp, catch_failures: true)
+    apply_manifest(pp, catch_changes: true)
+    # The automounter can retrun before it is actually working.
+    shell('sleep 10')
+    shell('ls /cvmfs/cms.cern.ch', acceptable_exit_codes: 0)
+  end
+
+  describe service('cvmfs-client-prometheus.socket') do
+    it { is_expected.to be_enabled }
+    it { is_expected.to be_running }
+  end
+
+  describe port('9868') do
+    it { is_expected.to be_listening }
+  end
+
+  describe command('curl -s http://localhost:9868/metrics') do
+    its(:stdout) { is_expected.to match(%r{^# HELP}) }
+  end
+end

spec/classes/init_spec.rb

@@ -30,6 +30,11 @@
         it { is_expected.to contain_concat__fragment('cvmfs_default_local_header').without_content(%r{^CVMFS_UID_MAP.*$}) }
         it { is_expected.to contain_concat__fragment('cvmfs_default_local_header').without_content(%r{^CVMFS_GID_MAP.*$}) }
 
+        it {
+          is_expected.to contain_package('prometheus-cvmfs-exporter').with_ensure('absent')
+          is_expected.to contain_service('cvmfs-client-prometheus.socket').with_ensure(false).with_enable(false)
+        }
+
         case facts[:os]['family']
         when 'Debian'
           it { is_expected.to contain_class('cvmfs::apt') }
@@ -49,6 +54,17 @@
           it { is_expected.to contain_concat__fragment('cvmfs_default_local_header').with_content(%r{^CVMFS_HTTP_PROXY='http://foobar.example.org:3128'$}) }
         end
 
+        context 'with enable_prometheus_exporter set true' do
+          let(:params) do
+            super().merge(enable_prometheus_exporter: true)
+          end
+
+          it {
+            is_expected.to contain_package('prometheus-cvmfs-exporter').with_ensure('installed')
+            is_expected.to contain_service('cvmfs-client-prometheus.socket').with_ensure(true).with_enable(true)
+          }
+        end
+
         context 'with defaults and cvmfspartsize fact unset' do
           it { is_expected.to contain_class('cvmfs::config') }
           it { is_expected.to contain_concat__fragment('cvmfs_default_local_header').with_content(%r{^CVMFS_QUOTA_LIMIT='1000'$}) }