Add an unattended_upgrades role that installs only Debian and Ubuntu security updates, with no automatic reboot

unattended_upgrades/defaults/main.yml

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+---
+unattended_upgrades:
+  # Security updates only. Third-party repositories (Docker, Kopia, CrowdSec, NetBird, Proxmox, GitLab) stay out:
+  # an update of docker-ce or a pve package restarts every container or guest.
+  # Keyed by ansible_distribution; Debian lists go to Origins-Pattern, Ubuntu lists to Allowed-Origins.
+  origins_pattern:
+    Debian:
+      - origin=Debian,codename=${distro_codename}-security,label=Debian-Security
+  allowed_origins:
+    Ubuntu:
+      - ${distro_id}:${distro_codename}-security
+      - ${distro_id}ESMApps:${distro_codename}-apps-security
+      - ${distro_id}ESM:${distro_codename}-infra-security
+  # Recipient of the report mail; unset sends none, as no host has an outgoing mail setup.
+  mail:
+  mail_report: only-on-error

unattended_upgrades/tasks/main.yml

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+---
+- name: Require an allowed origin for the distribution
+  ansible.builtin.assert:
+    that:
+      - (unattended_upgrades.origins_pattern[ansible_distribution] | default([]) + unattended_upgrades.allowed_origins[ansible_distribution] | default([])) | length > 0
+    fail_msg: unattended_upgrades has no origins for {{ ansible_distribution }}
+
+- name: Install unattended-upgrades
+  ansible.builtin.apt:
+    name: unattended-upgrades
+    state: present
+
+- name: Enable the daily package list update and upgrade
+  ansible.builtin.template:
+    src: 20auto-upgrades.j2
+    dest: /etc/apt/apt.conf.d/20auto-upgrades
+    mode: "0644"
+
+# Separate file, the package owns 50unattended-upgrades.
+- name: Configure unattended-upgrades
+  ansible.builtin.template:
+    src: 52unattended-upgrades-local.j2
+    dest: /etc/apt/apt.conf.d/52unattended-upgrades-local
+    mode: "0644"
+
+- name: Enable the apt timers
+  ansible.builtin.systemd:
+    name: "{{ item }}"
+    enabled: true
+    state: started
+  loop:
+    - apt-daily.timer
+    - apt-daily-upgrade.timer

unattended_upgrades/templates/20auto-upgrades.j2

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+// {{ ansible_managed }}
+APT::Periodic::Update-Package-Lists "1";
+APT::Periodic::Unattended-Upgrade "1";
+APT::Periodic::AutocleanInterval "7";

unattended_upgrades/templates/52unattended-upgrades-local.j2

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+// {{ ansible_managed }}
+// Replaces the origins of 50unattended-upgrades; apt list options append otherwise.
+#clear Unattended-Upgrade::Allowed-Origins;
+#clear Unattended-Upgrade::Origins-Pattern;
+{% set patterns = unattended_upgrades.origins_pattern[ansible_distribution] | default([]) %}
+{% if patterns %}
+Unattended-Upgrade::Origins-Pattern {
+{% for origin in patterns %}
+    "{{ origin }}";
+{% endfor %}
+};
+{% endif %}
+{% set allowed = unattended_upgrades.allowed_origins[ansible_distribution] | default([]) %}
+{% if allowed %}
+Unattended-Upgrade::Allowed-Origins {
+{% for origin in allowed %}
+    "{{ origin }}";
+{% endfor %}
+};
+{% endif %}
+
+// No automatic reboot, the owner schedules those.
+Unattended-Upgrade::Automatic-Reboot "false";
+Unattended-Upgrade::Remove-Unused-Kernel-Packages "true";
+Unattended-Upgrade::Remove-New-Unused-Dependencies "true";
+Unattended-Upgrade::Remove-Unused-Dependencies "false";
+{% if unattended_upgrades.mail %}
+Unattended-Upgrade::Mail "{{ unattended_upgrades.mail }}";
+Unattended-Upgrade::MailReport "{{ unattended_upgrades.mail_report }}";
+{% endif %}