Ansible Role: promtail

Description

Deploy promtail using ansible. Supports amd64 and arm architectures. For recent changes, please check the CHANGELOG or have a look at github releases

Requirements

• Ansible >= 2.7

Role Variables

All variables which can be overridden are stored in defaults/main.yml file as well as in table below.

Name	Default Value	Description
promtail_version	"3.0.0"	promtail package version. Also accepts latest as parameter.
promtail_custom_checksum	""	Custom checksum for custom build promtail binaries
promtail_binary_local_dir	""	Allows to use local packages instead of ones distributed on github. As parameter it takes the path where zip archive of promtail is stored on host on which ansible is ran.
promtail_extra_args	[]	Allows to set extra arguments to the binary within the systemd service file.
promtail_config_dir	/etc/promtail	Directory for storing promtail configuration file
promtail_config_expand_env	"false"	value of promtail -config.expand-env option
promtail_config_file_sd_dir	"{{ promtail_config_dir }}/file_sd"	Default directory for file_sd discovery
promtail_config_file	"{{ promtail_config_dir }}/promtail.yml"	Configuration file used by promtail
promtail_system_user	promtail	User the promtail process will run at
promtail_system_group	"{{ promtail_system_user }}"	Group of the promtail user
promtail_user_additional_groups	"adm"	Additional groups to be added to promtail user to give access to allow scraping of specific log files
promtail_config_clients	see defaults/main.yml	promtail clients section
promtail_loki_server_url	http://127.0.0.1:3100	Server url where promtail will push its result
promtail_config_server	see defaults/main.yml	promtail server section
promtail_positions_directory	/var/lib/promtail	Path to the directory where promtail tracks scraped log positons
promtail_config_positions	{"filename": "{{ promtail_positions_directory }}/positions.yml"}	promtail positions section
promtail_config_scrape_configs	[]	promtail scrape_configs section
promtail_target_config	{}	promtail target_config section
promtail_log_level	"info"	Loglevel of promtail (one of: debug,info,warn,error )
promtail_config_include_default_file_sd_config	"True"	When set to false, the default file_sd will not be provisioned
promtail_apt_update_cache	"True"	When set to false the role will not update the APT cache on its own

For each section (promtail_config_clients, promtail_config_server,promtail_config_positions,promtail_config_scrape_configs,promtail_target_config) the configuration can be passed accrodingly to the official promtail configuration. The role will converte the ansible vars into the respective yaml configuration for loki.

Example Playbook

Basic playbook that will assume that loki will be listening at http://127.0.0.1:3100 and a simple configuration to scrape /var/log logs:

---
- hosts: all
  roles:
    - role: patrickjahns.promtail
      vars:
        promtail_config_scrape_configs:
          - job_name: system
            static_configs:
            - targets:
                - localhost
              labels:
                job: varlogs
                __path__: /var/log/*log

A more complex example, that overrides server, client, positions configuration and provides a scrap configuration for /var/log:

---
- hosts: all
  roles:
    - role: patrickjahns.promtail
      vars:
        promtail_config_server:
          http_listen_port: 9080
          grpc_listen_port: 9081
        promtail_config_clients:
          - url: "http://prometheus.domain.tld:3100/loki/api/v1/push"
            external_labels:
              host: "{{ ansible_hostname }}"
        promtail_config_positions:
          filename: "{{ promtail_positions_directory }}/positions.yaml"
          sync_period: "60s"

        promtail_config_scrape_configs:
          - job_name: system
            static_configs:
            - targets:
                - localhost
              labels:
                job: varlogs
                __path__: /var/log/*log

Local Testing

The preferred way of locally testing the role is to use Docker and molecule (v3.x). You will have to install Docker on your system. See "Get started" for a Docker package suitable to for your system. We are using tox to simplify process of testing on multiple ansible versions. To install tox execute:

pip3 install tox

To run tests on all ansible versions (WARNING: this can take some time)

tox

To run a custom molecule command on custom environment with only default test scenario:

tox -e ansible29 -- molecule test -s default

For more information about molecule go to their docs.

If you would like to run tests on remote docker host just specify DOCKER_HOST variable before running tox tests.

CI

Github actions is used to test and validate this ansible role via ansible-later and molecule. Molecule tests will run with several operation systems as well as ansible version in order to ensure compatability.

License

This project is licensed under MIT License. See LICENSE for more details.

Maintainers and Contributors

• Patrick Jahns