Some improvements for apicert mode

Author: agapoff

README.md

@@ -27,16 +27,19 @@ Nagios-style checks against Kubernetes API. Designed for usage with Nagios, Icin
 	                    - Pod restart count in pods mode; default is 30
 	                    - Job failed count in jobs mode; default is 1
 	                    - Pvc storage utilization; default is 80%
+	                    - API cert expiration days for apicert mode; default is 30
 	  -c CRIT          Critical threshold for
 	                    - Pod restart count (in pods mode); default is 150
 	                    - Unbound Persistent Volumes in unboundpvs mode; default is 5
 	                    - Job failed count in jobs mode; default is 2
 	                    - Pvc storage utilization; default is 90%
+	                    - API cert expiration days for apicert mode; default is 15
 	  -M EXIT_CODE     Exit code when resource is missing; default is 2 (CRITICAL)
 	  -h               Show this help and exit
 
 	Modes are:
 	  apiserver        Not for kubectl, should be used for each apiserver independently
+	  apicert          Check the apicert expiration date
 	  nodes            Check for active nodes
 	  daemonsets       Check for daemonsets readiness
 	  deployments      Check for deployments availability
@@ -111,6 +114,10 @@ Check utilization if pvc (if consumes more than %):
     ./check_kubernetes.sh -m pvc
     CRITICAL. Very high storage utilization on pvc prometheus-data: 93% (86106636288/157459890176 Bytes)
 
+Check expiration date for API TLS certificate:
+    ./check_kubernetes.sh -m apicert -H https://<...>:6443 -T $TOKEN
+    OK. API cert expires in 278 days
+
 
 ## Brief mode (removed in v1.1.0)
 

check_kubernetes.sh

@@ -28,13 +28,13 @@ usage() {
 	                    - Pod restart count in pods mode; default is 30
 	                    - Job failed count in jobs mode; default is 1
 	                    - Pvc storage utilization; default is 80%
-                            - APICERT expiration days for apicert mode; default is 30
+	                    - API cert expiration days for apicert mode; default is 30
 	  -c CRIT          Critical threshold for
 	                    - Pod restart count (in pods mode); default is 150
 	                    - Unbound Persistent Volumes in unboundpvs mode; default is 5
 	                    - Job failed count in jobs mode; default is 2
 	                    - Pvc storage utilization; default is 90%
-                            - APICERT expiration days for apicert mode; default is 15
+	                    - API cert expiration days for apicert mode; default is 15
 	  -M EXIT_CODE     Exit code when resource is missing; default is 2 (CRITICAL)
 	  -h               Show this help and exit
 
@@ -159,27 +159,24 @@ mode_apicert() {
     fi
     WARN=${WARN:-30}
     CRIT=${CRIT:-15}
-    APICERT=$(echo "$APISERVER" | awk -F "//" '{ print $2 }' | awk -F ":" '{ print $1 }')
-    APIPORT=$(echo "$APISERVER" | awk -F "//" '{ print $2 }' | awk -F ":" '{ print $2 }')
-    APIPORT=${APIPORT:=443}
-    timeout "$TIMEOUT" bash -c "</dev/tcp/$APICERT/$APIPORT" &>/dev/null
-    if [ $? -ne 0 ]; then
-        echo "APICERT is in UNKNOWN"
+    APIHOST=$(echo "$APISERVER" | awk -F[/:] '{print $4}')
+    APIPORT=$(echo "$APISERVER" | awk -F[/:] '{print $5}')
+    APIPORT=${APIPORT:-443}
+    enddate=$(echo | openssl s_client -connect "$APIHOST:$APIPORT" 2>/dev/null | openssl x509 -enddate -noout 2>/dev/null | sed 's/notAfter=//' | xargs -r -0 date +%s -d)
+    if [ -z "$enddate" ]; then
+        echo "API cert expiration date is UNKNOWN"
         exit 3
     fi
-    APICERTDATE=$(echo | openssl s_client -connect "$APICERT":"$APIPORT" 2>/dev/null | openssl x509 -noout -dates | grep notAfter | sed -e 's#notAfter=##')
-    a=$(date -d "$APICERTDATE" +%s)
-    b=$(date +%s)
-    c=$((a-b))
-    d=$((c/3600/24))
-    echo "APICERT expires in $d days"
-    if [ "$d" -gt "$WARN" ]  && [ "$d" -gt "$CRIT" ]; then
-        echo "APICERT is OK"
-    elif [ "$d" -le "$WARN" ] && [ $d -gt "$CRIT" ]; then
-        echo "APICERT is in WARN"
+    nowdate=$(date +%s)
+    diff=$((($enddate-$nowdate)/24/3600))
+    OUTPUT="API cert expires in $diff days"
+    if [ "$diff" -gt "$WARN" ]  && [ "$diff" -gt "$CRIT" ]; then
+        OUTPUT="OK. $OUTPUT"
+    elif [ "$diff" -le "$WARN" ] && [ "$diff" -gt "$CRIT" ]; then
+        OUTPUT="WARNING. $OUTPUT"
         EXITCODE=1
-    elif [ "$d" -le "$CRIT" ]; then
-        echo "APICERT is in CRIT"
+    elif [ "$diff" -le "$CRIT" ]; then
+        OUTPUT="CRITICAL. $OUTPUT"
         EXITCODE=2
     fi
 }