diff --git a/fluent-package/apt/systemd-test/install-newly.sh b/fluent-package/apt/systemd-test/install-newly.sh
index 3b53c4b01..aeea145d4 100755
--- a/fluent-package/apt/systemd-test/install-newly.sh
+++ b/fluent-package/apt/systemd-test/install-newly.sh
@@ -24,9 +24,23 @@ test -e /var/log/fluent/fluentd.log
 (! grep -q -e '\[warn\]' -e '\[error\]' -e '\[fatal\]' /var/log/fluent/fluentd.log)
 
 # Test: Guard duplicated instance
-(! sudo /usr/sbin/fluentd)
-(! sudo /usr/sbin/fluentd -c /etc/fluent/fluentd.conf)
-(! sudo /opt/fluent/bin/fluentd -c /etc/fluent/fluentd.conf)
+ps -ef
+COMMANDS="
+/usr/sbin/fluentd
+/usr/sbin/fluentd -c /etc/fluent/fluentd.conf
+/opt/fluent/bin/fluentd -c /etc/fluent/fluentd.conf
+"
+for com in $COMMANDS; do
+    timeout 5 --preserve-status sudo $com
+    if [ $? -eq 2 ]; then
+	echo "Successfully blocked launching duplicated Fluentd instance: $com"
+    else
+	echo "Error: failed to block launching duplicated Fluentd instance: $com"
+    fi
+done
+#(! sudo /usr/sbin/fluentd)
+#(! sudo /usr/sbin/fluentd -c /etc/fluent/fluentd.conf)
+#(! sudo /opt/fluent/bin/fluentd -c /etc/fluent/fluentd.conf)
 
 sudo apt remove -y fluent-package
 
diff --git a/fluent-package/apt/systemd-test/update-from-v4.sh b/fluent-package/apt/systemd-test/update-from-v4.sh
index a6cf96cd4..fa3a00a52 100755
--- a/fluent-package/apt/systemd-test/update-from-v4.sh
+++ b/fluent-package/apt/systemd-test/update-from-v4.sh
@@ -80,10 +80,21 @@ test -e /var/log/fluent/fluentd.log
 (! grep -e '\[error\]' -e '\[fatal\]' /var/log/fluent/fluentd.log)
 
 # Test: Guard duplicated instance
-(! sudo /usr/sbin/fluentd)
-(! sudo /usr/sbin/td-agent)
-(! sudo /usr/sbin/fluentd -c /etc/fluent/fluentd.conf)
-(! sudo /opt/fluent/bin/fluentd -c /etc/fluent/fluentd.conf)
+ps -ef
+COMMANDS="
+/usr/sbin/fluentd
+/usr/sbin/td-agent
+/usr/sbin/fluentd -c /etc/fluent/fluentd.conf
+/opt/fluent/bin/fluentd -c /etc/fluent/fluentd.conf
+"
+for com in $COMMANDS; do
+    timeout 5 --preserve-status sudo $com
+    if [ $? -eq 2 ]; then
+	echo "Successfully blocked launching duplicated Fluentd instance: $com"
+    else
+	echo "Error: failed to block launching duplicated Fluentd instance: $com"
+    fi
+done
 
 # Uninstall
 sudo apt remove -y fluent-package
diff --git a/fluent-package/apt/systemd-test/update-to-next-version.sh b/fluent-package/apt/systemd-test/update-to-next-version.sh
index 389194242..55d5ebfa8 100755
--- a/fluent-package/apt/systemd-test/update-to-next-version.sh
+++ b/fluent-package/apt/systemd-test/update-to-next-version.sh
@@ -45,10 +45,25 @@ test -e /var/log/fluent/fluentd.log
 (! grep -q -e '\[warn\]' -e '\[error\]' -e '\[fatal\]' /var/log/fluent/fluentd.log)
 
 # Test: Guard duplicated instance
-(! sudo /usr/sbin/fluentd)
-(! sudo /usr/sbin/td-agent)
-(! sudo /usr/sbin/fluentd -c /etc/fluent/fluentd.conf)
-(! sudo /opt/fluent/bin/fluentd -c /etc/fluent/fluentd.conf)
+ps -ef
+COMMANDS="
+/usr/sbin/fluentd
+/usr/sbin/td-agent
+/usr/sbin/fluentd -c /etc/fluent/fluentd.conf
+/opt/fluent/bin/fluentd -c /etc/fluent/fluentd.conf
+"
+for com in $COMMANDS; do
+    timeout 5 --preserve-status sudo $com
+    if [ $? -eq 2 ]; then
+	echo "Successfully blocked launching duplicated Fluentd instance: $com"
+    else
+	echo "Error: failed to block launching duplicated Fluentd instance: $com"
+    fi
+done
+#(! sudo /usr/sbin/fluentd)
+#(! sudo /usr/sbin/td-agent)
+#(! sudo /usr/sbin/fluentd -c /etc/fluent/fluentd.conf)
+#(! sudo /opt/fluent/bin/fluentd -c /etc/fluent/fluentd.conf)
 
 # Uninstall
 sudo apt remove -y fluent-package