Config Controller for Alertmanager

This Config Controller is based on the Grafana Operator project. The Config Controller should be run within Kubernetes as a sidecar with the Prometheus Alertmanager.

It watches for new/updated/deleted ConfigMaps and if they define the specified annotations as true it will save each resource from ConfigMap to Alertmanagers local storage and reload the Alertmanager. This requires Alertmanager 0.16.x.

ConfigMap Annotations

Currently it supports three resources:

1. Receiver

alertmanager.net/receiver with values: "true" or "false"

2. Route

alertmanager.net/route with values: "true" or "false"

3. Inhibit Rule

alertmanager.net/inhibit_rule with values "true" or "false"

Config

alertmanager.net/config with values: "true" or "false"

alertmanager.net/key with values: string

Alertmanager will start with a provided minimal dummy config, which is definetly valid. Then the Config Controller will load the ConfigMap with annotation alertmanager.net/config: true, which includes the global Alertmanager configuration. The Config Controller will merge this configuration with the dummy configuration and only if this configuration is valid, Alertmanager will be reloaded. For each Alertmanager Setup there should be only one ConfigMap with annotation alertmanager.net/config: true. If you want to run e.g. three Alertmanagers in HA mode (replicas = 3), then all three Alertmanager will load the same ConfigMap and have the exact same config. To prevent other "nonadmin" users from misusing of alertmanager.net/config, a key is used. If and only if the key in ConfigMap matches the key in args of the Alertmanager Controller, the Controller will use the ConfigMap.

Id

alertmanager.net/id with values: "0" ... "n"

In case of multiple Alertmanager setups in same Kubernetes Cluster all the ConfigMaps have to be mapped to the right Alertmanager setup. So each ConfigMap can be additionaly annotated with the alertmanager.net/id (if not, the default id will be "0")

You can run e.g. three Alertmanagers in HA mode with id=0 and for an another setup with three Alertmanagers in HA mode with id=1, and so on.

Note

Mentioned "true" values can be also specified with: "1", "t", "T", "true", "TRUE", "True"

Mentioned "false" values can be also specified with: "0", "f", "F", "false", "FALSE", "False"

ConfigMap examples can be found here.

Usage

--run-outside-cluster # Uses local ~/.kube/config rather than in cluster configuration
--reloadUrl # Sets the URL to reload Alertmanager
--configPath # Sets the path to use to store config files
--configTemplate # Sets the location of template of the Alertmanager config
--id # Sets the ID, so the Controller knows which ConfigMaps should be watched
--key # Sets the key, so the Controller can recognize the template of config in ConfigMap

Development

Build

make build
# to run the linter, tests and build the binary, run
make ci

To build a docker image out of it, look at provided Dockerfile example which expects the alertmanager-config-controller binary in the same directory.

Deployment

Our preferred way to install alertmanager/alertmanager-config-controller is Helm. See example installation at our Helm directory within this repo.