From 3f139c41657ac648f40939b63066075bfb87775b Mon Sep 17 00:00:00 2001
From: Adrian Moisey <adrian@changeover.za.net>
Date: Mon, 21 Jul 2025 21:37:09 +0200
Subject: [PATCH 1/2] Add DNS lookup plugin

---
 config/network-problem-monitor.json |  6 ++++++
 config/plugin/dns_problem.sh        | 24 ++++++++++++++++++++++++
 2 files changed, 30 insertions(+)
 create mode 100755 config/plugin/dns_problem.sh

diff --git a/config/network-problem-monitor.json b/config/network-problem-monitor.json
index 7a4c48bf..6b13f436 100644
--- a/config/network-problem-monitor.json
+++ b/config/network-problem-monitor.json
@@ -15,6 +15,12 @@
       "reason": "ConntrackFull",
       "path": "./config/plugin/network_problem.sh",
       "timeout": "3s"
+    },
+    {
+      "type": "temporary",
+      "reason": "DNSUnreachable",
+      "path": "./config/plugin/dns_problem.sh",
+      "timeout": "3s"
     }
   ]
 }
diff --git a/config/plugin/dns_problem.sh b/config/plugin/dns_problem.sh
new file mode 100755
index 00000000..c31f7a66
--- /dev/null
+++ b/config/plugin/dns_problem.sh
@@ -0,0 +1,24 @@
+#!/bin/bash
+
+# This plugin checks for dns network issues.
+
+readonly OK=0
+readonly NONOK=1
+readonly UNKNOWN=2
+
+readonly KUBERNETES_SERVICE='kubernetes.default'
+
+# Check getent command is present
+if ! command -v getent >/dev/null; then
+  echo "Could not find 'getent' - require getent"
+  exit $UNKNOWN
+fi
+
+# Return success if a DNS lookup to the Kubernetes host is successful
+if getent hosts "${KUBERNETES_SERVICE}" >/dev/null; then
+  echo "DNS lookup to ${KUBERNETES_SERVICE} is working"
+  exit $OK
+else
+  echo "DNS lookup to ${KUBERNETES_SERVICE} is not working"
+  exit $NONOK
+fi

From bc3150aa62be4b930e1402927368ed736294e345 Mon Sep 17 00:00:00 2001
From: Adrian Moisey <adrian@changeover.za.net>
Date: Mon, 22 Sep 2025 15:11:07 +0200
Subject: [PATCH 2/2] Update config/plugin/dns_problem.sh

Co-authored-by: Dan Winship <danwinship@redhat.com>
---
 config/plugin/dns_problem.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/config/plugin/dns_problem.sh b/config/plugin/dns_problem.sh
index c31f7a66..231f6829 100755
--- a/config/plugin/dns_problem.sh
+++ b/config/plugin/dns_problem.sh
@@ -14,7 +14,7 @@ if ! command -v getent >/dev/null; then
   exit $UNKNOWN
 fi
 
-# Return success if a DNS lookup to the Kubernetes host is successful
+# Return success if a DNS lookup of the kubernetes service is successful
 if getent hosts "${KUBERNETES_SERVICE}" >/dev/null; then
   echo "DNS lookup to ${KUBERNETES_SERVICE} is working"
   exit $OK