COS Alerter

COS Alerter is intended to be used together with alertmanager and prometheus:

• Liveness of Alertmanager through an always-firing alert rule ("Watchdog")
• Liveness of COS Alerter itself from a metric endpoint it exposes and prometheus scrapes

Configuring Alertmanager

In order to integrate with COS Alerter you need to add a heartbeat rule to Prometheus and add a route to the Alertmanager config.

If you are using the Canonical Observability Stack, the alert rule is already created for you. If not, you can use a rule similar to the following:

- alert: Watchdog
  annotations:
    summary: A continuously firing alert that ensures Alertmanager is working correctly.
  expr: vector(1)
  labels:
    severity: none

Add the following to your alertmanager config to create the route:

receivers:
...
- name: cos-alerter
  webhook_configs:
  - url: http://<cos-alerter-address>:8080/alive?clientid=<clientid>&key=<clientkey>
route:
  ...
  routes:
  ...
  - matchers:
    - alertname = Watchdog
    receiver: cos-alerter
    group_wait: 0s
    group_interval: 1m
    repeat_interval: 1m

Note that group_wait should be set to 0s so the alert starts firing right away.

Configuring COS Alerter

Copy the file cos_alerter/config-defaults.yaml to /etc/cos-alerter.yaml (If running without docker) or ./cos-alerter (if running with docker). Edit the file with the appropriate values for your environment.

Running COS Alerter

Docker

The easiest way to run COS Alerter is to use docker.

docker run -p 8080:8080 --mount type=bind,source="$(pwd)"/cos-alerter.yaml,target=/etc/cos-alerter.yaml,readonly -it ghcr.io/canonical/cos-alerter:latest

Python

You can also run cos-alerter by installing the python package.

pip install cos-alerter
cos-alerter

Development Builds

See CONTRIBUTING.md for running development builds.