ansible: add alertmanager role

data/ansible/roles/alertmanager/defaults/main.yaml

@@ -0,0 +1,13 @@
+---
+alertmanager_version: 0.27.0
+alertmanager_user: alertmanager
+alertmanager_install_dir: /opt/alertmanager
+alertmanager_config_dir: /etc/alertmanager
+alertmanager_data_dir: /var/lib/alertmanager
+
+alertmanager_web_listen_address: 0.0.0.0:9093
+
+alertmanager_service_enabled: false
+alertmanager_service_state: stopped
+
+alertmanager_config_file: '{{ alertmanager_install_dir }}/alertmanager.yml'

data/ansible/roles/alertmanager/handlers/main.yaml

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+---
+- name: Restart alertmanager
+  become: true
+  ansible.builtin.systemd_service:
+    name: alertmanager
+    state: restarted
+    daemon_reload: true
+  when: alertmanager_service_state == 'started'

data/ansible/roles/alertmanager/tasks/main.yaml

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+---
+- name: Create alertmanager user
+  become: true
+  ansible.builtin.user:
+    name: '{{ alertmanager_user }}'
+    state: present
+    system: true
+    createhome: no
+
+- name: Check current Alertmanager version
+  ansible.builtin.command: "{{ alertmanager_install_dir }}/alertmanager --version"
+  register: alertmanager_current_version
+  ignore_errors: true
+  changed_when: false
+
+- name: Remove existing Alertmanager installation if version differs
+  become: true
+  ansible.builtin.file:
+    path: "{{ alertmanager_install_dir }}"
+    state: absent
+  when: alertmanager_current_version.rc == 0 and alertmanager_version not in alertmanager_current_version.stdout
+
+- name: Create alertmanager directories
+  become: true
+  ansible.builtin.file:
+    path: '{{ item }}'
+    state: directory
+    owner: '{{ alertmanager_user }}'
+    group: '{{ alertmanager_user }}'
+    mode: '0755'
+  loop:
+    - '{{ alertmanager_config_dir }}'
+    - '{{ alertmanager_data_dir }}'
+    - '{{ alertmanager_install_dir }}'
+
+- name: Download and extract alertmanager
+  become: true
+  ansible.builtin.unarchive:
+    src: 'https://github.com/prometheus/alertmanager/releases/download/v{{ alertmanager_version }}/alertmanager-{{ alertmanager_version }}.linux-amd64.tar.gz'
+    dest: '{{ alertmanager_install_dir }}'
+    remote_src: true
+    owner: '{{ alertmanager_user }}'
+    group: '{{ alertmanager_user }}'
+    extra_opts: [--strip-components=1]
+  notify: Restart alertmanager
+  when: alertmanager_current_version.rc != 0 or alertmanager_version not in alertmanager_current_version.stdout
+
+- name: Handle alertmanager config file
+  block:
+    - name: Copy file (if not .j2)
+      become: true
+      ansible.builtin.copy:
+        src: '{{ alertmanager_config_file }}'
+        dest: '{{ alertmanager_config_dir }}/{{ alertmanager_config_file | basename }}'
+        owner: '{{ alertmanager_user }}'
+        group: '{{ alertmanager_user }}'
+        mode: '0644'
+      when: not alertmanager_config_file.endswith('.j2')
+
+    - name: Template file (if .j2)
+      become: true
+      ansible.builtin.template:
+        src: '{{ alertmanager_config_file }}'
+        dest: '{{ alertmanager_config_dir }}/{{ alertmanager_config_file | basename | splitext | first }}'
+        owner: '{{ alertmanager_user }}'
+        group: '{{ alertmanager_user }}'
+        mode: '0644'
+      when: alertmanager_config_file.endswith('.j2')
+  when: alertmanager_config_file is defined
+  notify: Restart alertmanager
+
+- name: Create alertmanager systemd service file
+  become: true
+  ansible.builtin.template:
+    src: alertmanager.service.j2
+    dest: /etc/systemd/system/alertmanager.service
+    mode: '0644'
+  notify: Restart alertmanager
+
+- name: Ensure alertmanager service is in desired state
+  become: true
+  ansible.builtin.systemd_service:
+    name: alertmanager
+    state: '{{ alertmanager_service_state }}'
+    enabled: '{{ alertmanager_service_enabled }}'
+  when: alertmanager_service_state == 'stopped' or alertmanager_service_enabled == false

data/ansible/roles/alertmanager/templates/alertmanager.service.j2

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+[Unit]
+Description=Alertmanager
+Wants=network-online.target
+After=network-online.target
+
+[Service]
+User={{ alertmanager_user }}
+Group={{ alertmanager_user }}
+Type=simple
+ExecStart={{ alertmanager_install_dir }}/alertmanager \
+    --config.file={{ alertmanager_config_dir }}/alertmanager.yml \
+    --storage.path={{ alertmanager_data_dir }} \
+    --web.listen-address={{ alertmanager_web_listen_address }}
+Restart=always
+
+[Install]
+WantedBy=multi-user.target