fix: spark-k8s graceful shutdown on SIGTERM (#1564)

* fix: spark-k8s graceful shutdown on SIGTERM

* better formatting

* fixing pre-commit hook false positive

* fixing formatting

* update changelog

Author: Maleware

CHANGELOG.md

@@ -40,6 +40,7 @@ All notable changes to this project will be documented in this file.
 - spark: bump hadoop `3.4.2` to `3.4.3` ([#1533])
 - hive: Bump `4.2.0` to Hadoop `3.4.3` ([#1539]).
 - java-devel: Bump Maven to 3.9.16 ([#1548]).
+- spark: fix graceful shutdown at SIGTERM ([#1564])
 
 ### Fixed
 
@@ -95,6 +96,7 @@ All notable changes to this project will be documented in this file.
 [#1550]: https://github.com/stackabletech/docker-images/pull/1550
 [#1551]: https://github.com/stackabletech/docker-images/pull/1551
 [#1559]: https://github.com/stackabletech/docker-images/pull/1559
+[#1564]: https://github.com/stackabletech/docker-images/pull/1564
 
 ## [26.3.0] - 2026-03-16
 

spark-k8s/Dockerfile.3

@@ -258,4 +258,4 @@ EOF
 USER ${STACKABLE_USER_UID}
 
 WORKDIR ${SPARK_HOME}
-ENTRYPOINT [ "/stackable/run-spark.sh" ]
+ENTRYPOINT [ "/usr/bin/tini", "-s", "--", "/stackable/run-spark.sh" ]

spark-k8s/Dockerfile.4

@@ -230,4 +230,4 @@ EOF
 USER ${STACKABLE_USER_UID}
 
 WORKDIR ${SPARK_HOME}
-ENTRYPOINT [ "/stackable/run-spark.sh" ]
+ENTRYPOINT [ "/usr/bin/tini", "-s", "--", "/stackable/run-spark.sh" ]

spark-k8s/stackable/run-spark.sh

@@ -2,7 +2,21 @@
 
 eval "$_STACKABLE_PRE_HOOK"
 
-/stackable/spark/kubernetes/dockerfiles/spark/entrypoint.sh "$@"
+# Forward SIGTERM to the Spark entrypoint to support spark JVM's gracefully shutdown.
+/stackable/spark/kubernetes/dockerfiles/spark/entrypoint.sh "$@" &
+child_pid=$!
+
+# shellcheck disable=SC2329
+_handle_term() {
+  kill -TERM "$child_pid" 2>/dev/null || true
+}
+trap _handle_term TERM INT
+
+# `wait` returns immediately when the trap fires; loop until the child is actually gone.
+wait "$child_pid"
+while kill -0 "$child_pid" 2>/dev/null; do
+  wait "$child_pid" 2>/dev/null || true
+done
 result=$?
 
 eval "$_STACKABLE_POST_HOOK"