Add monitoring

Signed-off-by: Yohann D'ANELLO <ynerant@crans.org>

roles/prometheus-node-exporter/files/apt.sh

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+#!/bin/bash
+#
+# Description: Expose metrics from apt updates.
+#
+# Author: Ben Kochie <superq@gmail.com>
+
+upgrades="$(/usr/bin/apt-get --just-print dist-upgrade \
+  | /usr/bin/awk -F'[()]' \
+      '/^Inst/ { sub("^[^ ]+ ", "", $2); gsub(" ","",$2);
+                 sub("\\[", " ", $2); sub("\\]", "", $2); print $2 }' \
+  | /usr/bin/sort \
+  | /usr/bin/uniq -c \
+  | awk '{ gsub(/\\\\/, "\\\\", $2); gsub(/\"/, "\\\"", $2);
+           gsub(/\[/, "", $3); gsub(/\]/, "", $3);
+           print "apt_upgrades_pending{origin=\"" $2 "\",arch=\"" $NF "\"} " $1}'
+)"
+
+autoremove="$(/usr/bin/apt-get --just-print autoremove \
+  | /usr/bin/awk '/^Remv/{a++}END{printf "apt_autoremove_pending %d", a}'
+)"
+
+orphans="$(comm -23 \
+  <(dpkg-query -W -f '${db:Status-Abbrev}\t${Package}\n' \
+    | grep '^.[^nc]' | cut -f2 | sort) \
+  <(apt-cache dumpavail | sed -rn 's/^Package: (.*)/\1/p' | sort -u) \
+  | awk 'END{printf "apt_orphans %d", NR}'
+)"
+
+echo '# HELP apt_upgrades_pending Apt package pending updates by origin.'
+echo '# TYPE apt_upgrades_pending gauge'
+if [[ -n "${upgrades}" ]] ; then
+  echo "${upgrades}"
+else
+  echo 'apt_upgrades_pending{origin="",arch=""} 0'
+fi
+
+echo '# HELP apt_autoremove_pending Apt package pending autoremove.'
+echo '# TYPE apt_autoremove_pending gauge'
+echo "${autoremove}"
+
+echo '# HELP apt_orphans Orphan apt package.'
+echo '# TYPE apt_orphans gauge'
+echo "${orphans}"
+
+echo '# HELP node_reboot_required Node reboot is required for software updates.'
+echo '# TYPE node_reboot_required gauge'
+if [[ -f '/run/reboot-required' ]] ; then
+  echo 'node_reboot_required 1'
+else
+  echo 'node_reboot_required 0'
+fi

roles/prometheus-node-exporter/handlers/main.yml

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+---
+- name: Restart prometheus-node-exporter
+  service:
+    name: prometheus-node-exporter
+    state: restarted

roles/prometheus-node-exporter/tasks/main.yml

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+---
+- name: Install Prometheus node-exporter
+  apt:
+    update_cache: true
+    name: prometheus-node-exporter
+    install_recommends: false  # Do not install smartmontools
+  register: apt_result
+  retries: 3
+  until: apt_result is succeeded
+
+- name: Install Prometheus node-exporter-collectors (bullseye)
+  apt:
+    update_cache: true
+    name: prometheus-node-exporter-collectors
+    install_recommends: false
+  register: apt_result
+  retries: 3
+  until: apt_result is succeeded
+  when:
+    - ansible_lsb.codename == 'bullseye'
+
+- name: Make Prometheus node-exporter listen on adm only
+  lineinfile:
+    path: /etc/default/prometheus-node-exporter
+    regexp: '^ARGS='
+    line: |
+      ARGS="--web.listen-address={{ prometheus_node_exporter.listen_addr }}:9100"
+  tags: restart-node-exporter
+
+- name: Activate prometheus-node-exporter service
+  systemd:
+    name: prometheus-node-exporter
+    enabled: true
+    state: started
+
+# Install new APT textfile collector, it might be upstreamed one day
+# https://github.com/prometheus-community/node-exporter-textfile-collector-scripts/pull/35
+- name: Patch APT textfile collector
+  copy:
+    src: apt.sh
+    dest: /usr/share/prometheus-node-exporter/apt.sh
+    owner: root
+    group: root
+    mode: 0755
+  when: ansible_distribution_release != "bullseye"