Format of prometheusRules in values.yaml for kube-prometheus helm charts

[IBMRob]

I am trying to configure my own rules when using the kube-prometheus helm charts. Looking at the charts, our understanding is that if "prometheusRules" is not defined in the override values.yaml then the default rules for that helm chart will be used which in this case means reading in the general.rules.yaml into the ConfigMap.

If we update the chart to support an empty value for prometheusRules we presumed this would result in a ConfigMap with no rules inside it but this does not happen. i.e.:

Code in values.yaml

prometheusRules: {}

Code in configmap.yaml

data:

{{- if .Values.prometheusRules }}

{{- $root := . }}

{{- range $key, $val := .Values.prometheusRules }}

{{ $key }}: |-

{{ $val | indent 4}}

{{- end }}

{{ else }}

general.rules: |-

{{- include "general.rules.yaml.tpl" . | indent 4}}

{{ end }}

This still pulls in the default general.rules.yaml. We are trying to work out what format we should be using for the prometheusRules so that we can supply multiple rule such as 

- alert: FdExhaustionClose

expr: predict_linear(fd_utilization[1h], 3600 * 4) > 1

for: 10m

labels:

severity: warning

annotations:

description: '{{`{{ $labels.job }}`}}: {{`{{ $labels.namespace }}`}}/{{`{{ $labels.pod }}`}} instance

will exhaust in file/socket descriptors within the next 4 hours'

summary: file descriptors soon exhausted

- alert: FdExhaustionClose

expr: predict_linear(fd_utilization[10m], 3600) > 1

for: 10m

labels:

severity: critical

annotations:

description: '{{`{{ $labels.job }}`}}: {{`{{ $labels.namespace }}`}}/{{`{{ $labels.pod }}`}} instance

will exhaust in file/socket descriptors within the next hour'

summary: file descriptors soon exhausted

 (I realise these are rules that are already there but one we get the format we can make the rules what ever we need.)

Anyone able to help us with this?

[IBMRob]

For reference for anyone else hitting this. To produce an empty but value config file for a specific chart use

exporter-node:

prometheusRules:

exporter-node.rules: |-

groups:

- name: exporter-node.rules

rules: 

The format to put in custom rules into the yaml is as follows:

# default rules are in templates/general.rules.yaml

prometheusRules:

general.rules: |-

groups:

- name: general.rules

rules:

- record: fd_utilization

expr: process_open_fds / process_max_fds

- alert: FdExhaustionClose

expr: predict_linear(fd_utilization[1h], 3600 * 4) > 1

for: 10m

labels:

severity: warning

where: "<location>"

annotations:

description: '{{ $labels.job }}: {{ $labels.namespace }}/{{ $labels.pod }} instance

will exhaust in file/socket descriptors within the next 4 hours' - Playbook appconn#100