ansible-infra/ansible_collections/grafana/grafana/roles/promtail

Ansible role - Promtail

The Ansible Promtail Role allows you to effortlessly deploy and manage Promtail, agent which ships contents of local logs to private Loki. This role is tailored for operating systems such as RedHat, Rocky Linux, AlmaLinux, Ubuntu, and Debian.

🔑 Key Features

• ⚡ Root-less/Root runtime: By default, Promtail operates in root-less mode, utilizing ACL (Access Control List) to securely access logs without requiring root permissions. You have the option to configure root mode if necessary.
• 🧹 Effortless Uninstall: Easily remove Promtail from your system setting the "promtail_uninstall" variable.

📢 Check the blog post 📝 Learn more about root-less mode.

Table of Content

• Requirements
• Role Variables
• Playbook

Requirements

• Ansible 2.10+

Role Variables

promtail_version: "latest"

The version of Promtail to download and deploy. Supported standard version "3.0.0" format or "latest".

promtail_uninstall: "false"

If set to true will perfom uninstall instead of deployment.

promtail_http_listen_port: 9080

The TCP port on which Promtail listens. By default, it listens on port 9080.

promtail_http_listen_address: "0.0.0.0"

The address on which Promtail listens for HTTP requests. By default, it listens on all interfaces.

promtail_expose_port: false

By default, this is set to false. It supports only simple firewalld configurations. If set to true, a firewalld rule is added to expose the TCP promtail_http_listen_port. If set to false, configuration is skipped. If the firewalld.service is not active, all firewalld tasks are skipped.

promtail_positions_path: "/var/lib/promtail"

Promtail path for position file. File indicating how far it has read into a file. It is needed for when Promtail is restarted to allow it to continue from where it left off.

promtail_runtime_mode: "acl"

By default, Promtail runs in root-less mode. It supports two modes:

• acl: Root-less mode, utilizing ACL permission model to read target log files.
• root: Root mode, where Promtail runs as root and ACL configuration is skipped.

promtail_extra_flags: []

Additional flags to be passed to the Promtail systemd unit.

promtail_user_append_groups:
  - "systemd-journal"

Appends the promtail user to specific groups in root-less mode. By default, it appends the user to the systemd-journal group, granting permission to read system journal logs.

promtail_download_url_rpm: "https://github.com/grafana/loki/releases/download/v{{ promtail_version }}/promtail-{{ promtail_version }}.{{ __promtail_arch }}.rpm"

The default download URL for the Promtail rpm package from GitHub.

promtail_download_url_deb: "https://github.com/grafana/loki/releases/download/v{{ promtail_version }}/promtail_{{ promtail_version }}_{{ __promtail_arch }}.deb"

The default download URL for the Promtail deb package from GitHub.

promtail_server:
  http_listen_port: "{{ promtail_http_listen_port }}"
  http_listen_address: "{{ promtail_http_listen_address }}"

The server block configures Promtail behavior as an HTTP server. All possible values for server

promtail_positions:
  filename: "{{ promtail_positions_path }}/positions.yaml"

The positions block configures where Promtail will save a file indicating how far it has read into a file. It is needed for when Promtail is restarted to allow it to continue from where it left off. All possible values for positions

promtail_clients:
  - url: http://localhost:3100/loki/api/v1/push

The clients block configures how Promtail connects to instances of Loki. All possible values for clients. ⚠️ This configuration is mandatory. By default, it's empty, and the example above serves as a simple illustration for inspiration.

promtail_scrape_configs:
  - job_name: system
    static_configs:
      - targets:
          - localhost
        labels:
          job: messages
          instance: "{{ ansible_facts['fqdn'] }}"
          __path__: /var/log/messages
      - targets:
          - localhost
        labels:
          job: nginx
          instance: "{{ ansible_facts['fqdn'] }}"
          __path__: /var/log/nginx/*.log

The scrape_configs block configures how Promtail can scrape logs from a series of targets using a specified discovery method. All possible values for scrape_configs. ⚠️ This configuration is mandatory. By default, it's empty, and the example above serves as a simple illustration for inspiration.

Variable Name	Description
promtail_limits_config	The optional limits_config block configures global limits for this instance of Promtail. 📚 documentation.
promtail_target_config	The target_config block controls the behavior of reading files from discovered targets. 📚 documentation.

Dependencies

No Dependencies

Playbook

- name: Manage promtail service
  hosts: all
  become: true
  vars:
    promtail_clients:
      - url: http://localhost:3100/loki/api/v1/push
    promtail_scrape_configs:
      - job_name: system
        static_configs:
          - targets:
              - localhost
            labels:
              job: messages
              instance: "{{ ansible_facts['fqdn'] }}"
              __path__: /var/log/messages
          - targets:
              - localhost
            labels:
              job: nginx
              instance: "{{ ansible_facts['fqdn'] }}"
              __path__: /var/log/nginx/*.log
  roles:
    - role: grafana.grafana.promtail

• Playbook execution example

# Deploy Promtail
ansible-playbook function_promtail_play.yml

# Uninstall Promtail
ansible-playbook function_promtail_play.yml -e "promtail_uninstall=true"

License

See LICENSE

Author Information

• VoidQuark