matrix-docker-ansible-deploy/docs/configuring-playbook-alertmanager-receiver.md

Setting up Prometheus Alertmanager integration via matrix-alertmanager-receiver (optional)

The playbook can install and configure the matrix-alertmanager-receiver service for you. It's a client for Prometheus' Alertmanager, allowing you to deliver alerts to Matrix rooms.

See the project's documentation to learn more about what this component does and why it might be useful to you.

At the moment, setting up this service's bot requires some manual actions as described below in Account and room preparation.

This service is meant to be used with an external Alertmanager instance. It's not meant to be integrated with the Prometheus & Grafana stack installed by this playbook, because the Alertmanager component is not installed by it.

Adjusting the playbook configuration

To enable matrix-alertmanager-receiver, add the following configuration to your inventory/host_vars/matrix.example.com/vars.yml file:

matrix_alertmanager_receiver_enabled: true

# If you'd like to change the username for this bot, uncomment and adjust. Otherwise, remove.
# matrix_alertmanager_receiver_config_matrix_user_id_localpart: "bot.alertmanager.receiver"

# Specify the bot user's access token here.
# See the "Account and room preparation" section below.
matrix_alertmanager_receiver_config_matrix_access_token: ''

# Optionally, configure some mappings (URL-friendly room name -> actual Matrix room ID).
#
# If you don't configure mappings, you can still deliver alerts using URLs like this:
# https://matrix.example.com/matrix-alertmanager-receiver-RANDOM_VALUE_HERE/alert/!qporfwt:example.com
#
# If a mapping like the one below is configured, you can deliver alerts using friendlier URLs like this:
# https://matrix.example.com/matrix-alertmanager-receiver-RANDOM_VALUE_HERE/alert/some-room-name
matrix_alertmanager_receiver_config_matrix_room_mapping:
  some-room-name: "!qporfwt:{{ matrix_domain }}"

See roles/custom/matrix-alertmanager-receiver/defaults/main.yml for additional configuration variables.

Adjusting the matrix-alertmanager-receiver URL

By default, this playbook installs matrix-alertmanager-receiver on the matrix. subdomain, at the /matrix-alertmanager-receiver path (https://matrix.example.com/matrix-alertmanager-receiver). This makes it easy to install it, because it doesn't require additional DNS records to be set up. If that's okay, you can skip this section.

By tweaking the matrix_alertmanager_receiver_hostname and matrix_alertmanager_receiver_path_prefix variables, you can easily make the service available at a different hostname and/or path than the default one.

Example additional configuration for your inventory/host_vars/matrix.example.com/vars.yml file:

# Change the default hostname and path prefix
matrix_alertmanager_receiver_hostname: alertmanager.example.com
matrix_alertmanager_receiver_path_prefix: /

Adjusting DNS records

If you've changed the default hostname, you may need to adjust your DNS records to point the matrix-alertmanager-receiver domain to the Matrix server.

See Configuring DNS for details about DNS changes.

If you've decided to use the default hostname, you won't need to do any extra DNS configuration.

Account and room preparation

The playbook can automatically create users, but it cannot automatically obtain access tokens, nor perform any of the other manual actions below.

matrix-alertmanager-receiver uses a bot (with a username specified in matrix_alertmanager_receiver_config_matrix_user_id_localpart - see above) for delivering messages. You need to manually register this bot acccount and obtain an access token for it.

1. Register a new user: ansible-playbook -i inventory/hosts setup.yml --extra-vars='username=bot.alertmanager.receiver password=PASSWORD_FOR_THE_BOT admin=no' --tags=register-user
2. Obtain an access token for the bot's user account
3. Invite the bot to a room where you'd like to alerts to be delivered
4. Log in as the bot using any Matrix client of your choosing, accept the room invitation from the bot's account and log out
5. (Optionally) Adjust matrix_alertmanager_receiver_config_matrix_room_mapping to create a mapping between the new room and its ID

Steps 1 and 2 above only need to be done once, while preparing your configuration.

Steps 3 and 4 need to be done for each new room you'd like the bot to deliver alerts to. Step 5 is optional and provides cleaner /alert/ URLs.

Installing

Now that you've prepared the bot account and room, configured the playbook, and potentially adjusted your DNS records, you can run the playbook with playbook tags as below:

ansible-playbook -i inventory/hosts setup.yml --tags=setup-all,ensure-matrix-users-created,start

Notes:

• The ensure-matrix-users-created playbook tag makes the playbook automatically create the bot's user account.

• The shortcut commands with the just program are also available: just install-all or just setup-all

  just install-all is useful for maintaining your setup quickly when its components remain unchanged. If you adjust your vars.yml to remove other components, you'd need to run just setup-all, or these components will still remain installed.

Usage

Configure your Prometheus Alertmanager with configuration like this:

receivers:
  - name: matrix
    webhook_configs:
      - send_resolved: true
        url: URL_HERE
route:
  group_by:
    - namespace
  group_interval: 5m
  group_wait: 30s
  receiver: "matrix"
  repeat_interval: 12h
  routes:
    - receiver: matrix

.. where URL_HERE looks like https://matrix.example.com/matrix-alertmanager-receiver-RANDOM_VALUE_HERE/alert/some-room-name or https://matrix.example.com/matrix-alertmanager-receiver-RANDOM_VALUE_HERE/alert/!qporfwt:example.com.

This bot does not accept room invitations automatically (like many other bots do). To deliver messages to rooms, the bot must be joined to all rooms manually - see Step 4 of the Account and room preparation section.