From d791101782fb99c88a60e0c4f4a5420abf9f0279 Mon Sep 17 00:00:00 2001
From: abd-ulbasit <basit@basit.engineer>
Date: Thu, 22 Oct 2026 00:18:20 +0500
Subject: [PATCH] fix(cluster): let the low disk space alerts match WAL and
 tablespace PVCs

The podSelector passed to the PrometheusRule templates ends with "$".
The low disk space rules append "-wal" and "-tbs.*" to it, so those
matchers render as "<cluster>-([1-9][0-9]*)$-wal" and never match. A
full WAL or tablespace volume does not raise
CNPGClusterLowDiskSpaceWarning or CNPGClusterLowDiskSpaceCritical.

Drop the "$". Prometheus anchors =~ matchers at both ends, so the other
matchers built from podSelector (the pod matchers and the PGDATA PVC
matchers) select the same series as before.

Check the rendered WAL and tablespace matchers in the monitoring
chainsaw test.

Closes #966

Assisted-by: Claude Opus 5.5
Signed-off-by: abd-ulbasit <basit@basit.engineer>
---
 charts/cluster/templates/prometheus-rule.yaml              | 2 +-
 .../test/monitoring/01-monitoring_cluster-assert.yaml      | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/charts/cluster/templates/prometheus-rule.yaml b/charts/cluster/templates/prometheus-rule.yaml
index fc3f35cb4d..2af43498c2 100644
--- a/charts/cluster/templates/prometheus-rule.yaml
+++ b/charts/cluster/templates/prometheus-rule.yaml
@@ -17,7 +17,7 @@ spec:
         {{- $_ := set $dict "namespace"   (include "cluster.namespace" .) -}}
         {{- $_ := set $dict "cluster"     (include "cluster.fullname" .) -}}
         {{- $_ := set $dict "labels"      (dict "job" "{{ $labels.job }}" "node" "{{ $labels.node }}" "pod" "{{ $labels.pod }}") -}}
-        {{- $_ := set $dict "podSelector" (printf "%s-([1-9][0-9]*)$" (include "cluster.fullname" .)) -}}
+        {{- $_ := set $dict "podSelector" (printf "%s-([1-9][0-9]*)" (include "cluster.fullname" .)) -}}
         {{- $_ := set $dict "Values"      .Values -}}
         {{- $_ := set $dict "Template"    .Template -}}
         {{- range $path, $_ := .Files.Glob  "prometheus_rules/**.yaml" }}
diff --git a/charts/cluster/test/monitoring/01-monitoring_cluster-assert.yaml b/charts/cluster/test/monitoring/01-monitoring_cluster-assert.yaml
index ff2d676bcc..d5b561af79 100644
--- a/charts/cluster/test/monitoring/01-monitoring_cluster-assert.yaml
+++ b/charts/cluster/test/monitoring/01-monitoring_cluster-assert.yaml
@@ -120,6 +120,13 @@ spec:
         labels:
           environment: staging
           oncall: "false"
+      # the low disk space alerts must also match the WAL and tablespace PVCs
+      (rules[?alert == 'CNPGClusterLowDiskSpaceCritical'] | [0]):
+        (contains(expr, 'persistentvolumeclaim=~"monitoring-cluster-([1-9][0-9]*)-wal"')): true
+        (contains(expr, 'persistentvolumeclaim=~"monitoring-cluster-([1-9][0-9]*)-tbs.*"')): true
+      (rules[?alert == 'CNPGClusterLowDiskSpaceWarning'] | [0]):
+        (contains(expr, 'persistentvolumeclaim=~"monitoring-cluster-([1-9][0-9]*)-wal"')): true
+        (contains(expr, 'persistentvolumeclaim=~"monitoring-cluster-([1-9][0-9]*)-tbs.*"')): true
 ---
 apiVersion: v1
 kind: ConfigMap