heimdall

README

Heimdall

Heimdall watches Ingresses in your Kubernetes cluster to create PrometheusRules based off annotations and PrometheusRule templates.

Configuring PrometheusRules via annotations makes it easy for cluster users to set up relevant alerts for Ingresses with a single-line annotation. Cluster operators can configure Heimdall and other components to ensure cluster users have a consistent set of PrometheusRules.

PrometheusRule Templates

Heimdall needs templates for the PrometheusRules it will create. These are standard go template files. An example template can be found here. By default, Heimdall will look for a folder called templates to find these in. You can override this with the --templates flag.

Ingress Annotations

Your Ingress must have annotations in the form of:

com.uswitch.heimdall/<prometheus-rule-name>: <threshold>

For example:

com.uswitch.heimdall/5xx-rate: "0.001"

This will create a PrometheusRule based on the 5xx-rate.tmpl template with a threshold of 0.001.

Requirements

Heimdall uses PrometheusRules – custom resource definitions of Prometheus Operator.

PrometheusRule CRD must be added to the cluster prior to deploying Heimdall:

kubectl apply -f https://raw.githubusercontent.com/coreos/prometheus-operator/master/example/prometheus-operator-crd/prometheusrule.crd.yaml

Your monitoring pipeline would likely depend on Prometheus Operator to:

• manage Prometheus StatefulSets
• manage Alertmanager StatefulSets
• watch PrometheusRule CRDs and create corresponding ConfigMaps
• reload Prometheus instance when ConfigMap changes

Flags

--help                   Show context-sensitive help.
--kubeconfig=KUBECONFIG  Path to kubeconfig.
--namespace=""           Namespace to monitor
--debug                  Debug mode
--json                   Output log data in JSON format
--templates="templates"  Directory for the templates
--sync-interval=1m       Synchronize list of Ingress resources this frequently