Redis Sentinel - handle SIGTERM in kubectl-shared container

When Redis Sentinel has the master service option enabled, the `kubectl-shared` container runs a script with an infinite `while+sleep` loop. This script does not handle SIGTERM and causes the pod to hang upon termination until the termination grace period elapses. This change introduces a `preStop` hack to create a `terminate` file, which is used as a singal to the script that it should exit the infinite loop Signed-off-by: Kevin Pullin <[email protected]>
bitnami · Feb 20, 2025 · a327f3c · a327f3c
1 parent 9d61546
commit a327f3c
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diff --git a/bitnami/redis/Chart.yaml b/bitnami/redis/Chart.yaml
@@ -36,4 +36,4 @@ maintainers:
 name: redis
 sources:
 - https://github.com/bitnami/charts/tree/main/bitnami/redis
-version: 20.8.0
+version: 20.8.1
diff --git a/bitnami/redis/templates/scripts-configmap.yaml b/bitnami/redis/templates/scripts-configmap.yaml
@@ -807,15 +807,23 @@ data:
   update-master-label.sh: |
     #!/bin/bash
     while true; do
-        while [ ! -f "/etc/shared/current" ]; do
+        while [ ! -f "/etc/shared/current" ] && [ ! -f "/etc/shared/terminate" ]; do
             sleep 1
         done
-        echo "new master elected, updating label(s)..."
-        kubectl label pod --field-selector metadata.name="$(< "/etc/shared/current")" isMaster="true" --overwrite
-        kubectl label pod --field-selector metadata.name="$(< "/etc/shared/current")" app.kubernetes.io/role-
-        if [ -f /etc/shared/previous ]; then
-            kubectl label pod --field-selector metadata.name="$(< "/etc/shared/previous")" isMaster="false" --overwrite
+
+        if [ -f "/etc/shared/current" ]; then
+            echo "new master elected, updating label(s)..."
+            kubectl label pod --field-selector metadata.name="$(< "/etc/shared/current")" isMaster="true" --overwrite
+            kubectl label pod --field-selector metadata.name="$(< "/etc/shared/current")" app.kubernetes.io/role-
+            if [ -f /etc/shared/previous ]; then
+                kubectl label pod --field-selector metadata.name="$(< "/etc/shared/previous")" isMaster="false" --overwrite
+            fi
+            rm "/etc/shared/current" "/etc/shared/previous"
+        fi
+
+        if [ -f "/etc/shared/terminate" ]; then
+            echo "received signal to terminate"
+            exit
         fi
-        rm "/etc/shared/current" "/etc/shared/previous"
     done
 {{- end }}
diff --git a/bitnami/redis/templates/sentinel/statefulset.yaml b/bitnami/redis/templates/sentinel/statefulset.yaml
@@ -615,6 +615,12 @@ spec:
           image: {{ template "redis.kubectl.image" . }}
           imagePullPolicy: {{ .Values.kubectl.image.pullPolicy | quote }}
           command: {{- toYaml .Values.kubectl.command | nindent 12 }}
+          lifecycle:
+            preStop:
+              exec:
+                command:
+                  - touch
+                  - /etc/shared/terminate
           {{- if .Values.kubectl.containerSecurityContext.enabled }}
           securityContext: {{- include "common.compatibility.renderSecurityContext" (dict "secContext" .Values.kubectl.containerSecurityContext "context" $) | nindent 12 }}
           {{- end }}