diff --git a/builder/Dockerfile b/builder/Dockerfile
index a00fde24..6beedf6b 100644
--- a/builder/Dockerfile
+++ b/builder/Dockerfile
@@ -44,4 +44,7 @@ RUN mkdir -p /var/empty /etc/haproxy /var/lib/haproxy /var/run/haproxy\
 
 STOPSIGNAL SIGTERM
 USER haproxy
+
+# dumb-init reaps the old haproxy process in the embedded, non master-worker mode,
+# after receiving SIGUSR1, avoiding it to become a zombie.
 ENTRYPOINT ["/usr/bin/dumb-init", "--", "/start.sh"]
diff --git a/pkg/haproxy/instance.go b/pkg/haproxy/instance.go
index ed7ca7ee..6dba450e 100644
--- a/pkg/haproxy/instance.go
+++ b/pkg/haproxy/instance.go
@@ -637,6 +637,7 @@ func (i *instance) startHAProxySync() {
 		"-f", i.options.HAProxyCfgDir)
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr
+	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
 	if err := cmd.Start(); err != nil {
 		i.logger.Error("error starting haproxy: %v", err)
 		return
diff --git a/rootfs/Dockerfile b/rootfs/Dockerfile
index d5ece7ed..fb1d8d0e 100644
--- a/rootfs/Dockerfile
+++ b/rootfs/Dockerfile
@@ -27,4 +27,7 @@ RUN mkdir -p /var/empty /etc/haproxy /var/lib/haproxy /var/run/haproxy\
 
 STOPSIGNAL SIGTERM
 USER haproxy
+
+# dumb-init reaps the old haproxy process in the embedded, non master-worker mode,
+# after receiving SIGUSR1, avoiding it to become a zombie.
 ENTRYPOINT ["/usr/bin/dumb-init", "--", "/start.sh"]