From fb12f3b70eff147c6ffe9f36686e6f230255b017 Mon Sep 17 00:00:00 2001
From: Rohit Ramkumar <rramkumar@google.com>
Date: Mon, 27 Nov 2017 11:33:38 -0800
Subject: [PATCH] Add network monitor script as plugin

---
 config/network-problem-monitor.json | 18 ++++++++++++++++++
 config/plugin/network_problem.sh    | 15 +++++++++++++++
 2 files changed, 33 insertions(+)
 create mode 100644 config/network-problem-monitor.json
 create mode 100755 config/plugin/network_problem.sh

diff --git a/config/network-problem-monitor.json b/config/network-problem-monitor.json
new file mode 100644
index 00000000..1a2a5764
--- /dev/null
+++ b/config/network-problem-monitor.json
@@ -0,0 +1,18 @@
+{
+  "plugin": "custom",
+  "pluginConfig": {
+    "invoke_interval": "30s",
+    "timeout": "5s",
+    "max_output_length": 80,
+    "concurrency": 3
+  },
+  "source": "network-custom-plugin-monitor",
+  "rules": [
+    {
+      "type": "temporary",
+      "reason": "ConntrackFull",
+      "path": "./config/plugin/network_problem.sh",
+      "timeout": "3s"
+    }
+  ]
+}
diff --git a/config/plugin/network_problem.sh b/config/plugin/network_problem.sh
new file mode 100755
index 00000000..645a84b0
--- /dev/null
+++ b/config/plugin/network_problem.sh
@@ -0,0 +1,15 @@
+#!/bin/bash
+
+# This plugin checks for common network issues. Currently, it only checks
+# if the conntrack table is full. 
+
+conntrack_max=$(cat /proc/sys/net/ipv4/netfilter/ip_conntrack_max)
+conntrack_count=$(cat /proc/sys/net/ipv4/netfilter/ip_conntrack_count)
+if (( conntrack_count >= conntrack_max )); then
+  echo "Conntrack table full"
+  exit 1
+fi
+
+echo "Conntrack table available"
+exit 0
+