无法通过 systemd 使用 userdata 启动应用程序作为服务

Question

I want to start my app as service from systemd but the app is not starting.

My unit file appstart.service looks like this:

[Unit]
Description=Application start

[Service]
Type=simple
User=ec2-user
ExecStart=/usr/bin/bash /home/ec2-user/project/restartScript.sh
SyslogIdentifier=App_start

[Install]
WantedBy=multi-user.target

RestartScript.sh should start the java app:

#!/bin/bash
export SPRING_PROFILES_ACTIVE="tst,development"
cd /home/ec2-user/project
pkill java
/usr/bin/java -jar /home/ec2-user/project/app.jar >>/home/ec2-user/project/web.log 2>>/home/ec2-user/project/web-error.log &

I am starting the app as a service this way using User Data on AWS EC2 instance:

#!/bin/bash
mkdir /home/ec2-user/project
cd /home/ec2-user/project
sudo wget -P /home/ec2-user/project/ https://tst.s3.eu-west-1.amazonaws.com/app.jar
chown -R ec2-user:ec2-user /home/ec2-user/project
sudo wget -P /home/ec2-user/project/ https://tst.s3.eu-west-1.amazonaws.com/restartScript.sh
sudo chmod 755 /home/ec2-user/project/restartScript.sh
cd /etc/systemd/system/
sudo wget /etc/systemd/system/ https://tst.s3.eu-west-1.amazonaws.com/appstart.service
sudo su 
systemctl daemon-reload
systemctl enable appstart.service
systemctl start appstart.service
exit

The output I am getting when I start the EC2 instance this way is:

$ systemctl status appstart.service
● appstart.service - Application start
   Loaded: loaded (/etc/systemd/system/appstart.service; enabled; vendor preset: disabled)
   Active: inactive (dead) since Thu 2022-08-25 13:35:52 UTC; 4min 19s ago
  Process: 7328 ExecStart=/usr/bin/bash /home/ec2-user/project/restartScript.sh (code=exited, status=0/SUCCESS)
 Main PID: 7328 (code=exited, status=0/SUCCESS)

Aug 25 13:35:52 ip-x-x-x-x.tst.local systemd[1]: Started Application start.

When I try to do systemctl start appstart.service Nothing changes. The application is not working.

Any idea why is this happening?

OS on the machine:

$ cat /etc/os-release
NAME="Amazon Linux"
VERSION="2"
ID="amzn"
ID_LIKE="centos rhel fedora"

Answer 1

Nothing seems to be wrong with this, the service is running and the application runs and finishes successfully. The Active state of the service becomes inactive (dead) in case of failure it should be Failed and Main PID is (code=exited, status=0/SUCCESS) .

To verify that the service is running correct, write this line somewhere in RestartScript.sh :

echo "Test" > test.txt

After starting the service you will find the created file near RestartScript.sh file.

Answer 2

I managed to resolve the issue by changing the WantedBy section in appstart.service file to default.target.