Spring has this documentation for running an executable spring boot jar.
However, I ran this jar from terminal using the nohup linux command, and worked fine.
The question is: Using nohup or using init.d service, will have the same result for the application? Or using the init.d is the correct way always?
They do different things. nohup runs a command, and ignores the HANGUP (HUP) signal. init.d is for running a command automatically at server start-up (and shutting commands down orderly on shutdown). If you want your spring boot application to run automatically after the system restarts, put it in init.d - if you want to manually start it after every reboot you can use nohup.
nohup runs the command in a way that will be immune to hangups, which could cause problems. A lot of programs are designed to re-read their configuration files, restart, or do other things when they receive HUP signals (most services/daemons restart or re-read configs). Unless you specifically want to ignore HUP signals, using nohup isn't the best solution.
You can use & after the command in order to run it in the background, and if you want to avoid output to the terminal, you can send the output to /dev/null:
mycommand > /dev/null 2>&1 &
The 2>&1 will send stderr to stdout, so it goes to /dev/null.
Related
update：
I have followed spring boot deployment for Installation as an init.d Service (System V). I start my application successfully.But, after one day.My application closed again......Is there any ways to help me ?
I hava one spring boot application which names my.jar. I put it into my ubuntu server(20.04) and use the command of nohup java -jar my.jar &.In the first few hours, my application is in good condition.But,after one or two days,it will shut down automatically.
I have seen the log of my application which don't recorded any error and saved the last correct log before exiting
The current situation is my application is very simple and have only a small number of visits.
According to my guess,it is seems that ubuntu kill my process for inactivity?
My scripts are as follow,
stop.sh:
#!/bin/bash
PID=$(ps -ef | grep centre-0.0.1-SNAPSHOT.jar | grep -v grep | awk '{ print $2 }')
if [ -z "$PID" ]
then
echo Application is already stopped
else
echo kill $PID
kill $PID
fi
run.sh:
#!/bin/bash
echo stop application
source stop.sh
echo start application
source start.sh
start.sh:
#!/bin/bash
nohup java -jar centre-0.0.1-SNAPSHOT.jar &
I need my application will run all the time.
Is there any ways to resolve the issue?
nohup is more suited for running processes that are expected to end after a while. For example running a lengthy batch script.
As of why it is killed, there may be a number of reasons: memory leak, server security policy .... The server probably decided your program wasn't behaving correctly. Logs of the server, like dmesg or /var/log/ contents may have some clues about it.
What you said about your app receiving visits feels like it is more a service rather than a script.
You may want to
daemonize your program
. this will make your program tied to the server availability.
Here is an explanation of the differences between nohup and daemons.
Also check this link at baeldung for help on setting up the daemon
After I check the memory usage, so I realized that my spring boot have used a lot of memory abnormally.
I solved it in the following way:
I updated my start.sh with the command of "nohup java -Xms100m -Xmx300m -jar ./target/centre-0.0.1-SNAPSHOT.jar &"
But, I did not figure out why did my spring boot application use a lot of memory?
Is there anyone can explain this phenomenon?
I have a script.sh that set some environment variable and start a java server.
#!/bin/bash
export JAVA_HOME="/opt/java"
export ....
nohup $JAVA_HOME/bin/java "$MEMORY_JAVA_OPS" -classpath "$MY_CLASSPATH" $MAIN_CLASS &
I would like to transform this script (now is launched by /etc/rc.d/rc.local) in a service.
I tried many examples found online and over StackOverflow.
I created myservice.service file using many templates found online... No one work!
one example is:
[Unit]
Description=MyService Java Process Restart Upstart Script
After=auditd.service systemd-user-sessions.service time-sync.target
[Service]
User=root
TimeoutStartSec=0
Type=simple
KillMode=process
#export JAVA_HOME=/opt/java/jdk-9
#export PATH=$PATH:$JAVA_HOME/bin
WorkingDirectory=/tmp/myworkdir
ExecStart=/path/to/myscript.sh
[Install]
WantedBy=multi-user.target
With some configurations, the service starts but the status command says that it is dead (while it is actually running). With others it does not start. With none it stops with the command stop ....
I tried Type=Simple, forking, oneshot... always some problem.
I would simply that after boot or when user launch systemctl start myservice, service start, and if after some time crash will be started again. And if I will run systemclt stop myservice it stops and not need to kill the process.
Firstly it need to be said, that concept "service" greatly differs in Linux/Unix and Windows environment. From your question seems to me you are looking for Unix solution.
In unix you typically register some statup and stop script/command. The startup script just runs your java application via java -jar app.jar. This application does business logic & also opens listening on some SHUTDOWN port.
The stop script/command just invokes another (or the same with different cmd parameters) java application which does nothing else just sending STOP command to original application's SHUTDOWN port.
You can look in more detail for example on tomcat startup/stop scripts - they are doing exactly this.
For windows is better to use some wrappers like WinRun4J or whatever else. Of course you can have one multiplatform maven archetype for "universal multiplatform" service like we do.
EDITED:
If you are still unsure how to configure it on Linux, read https://linuxconfig.org/how-to-create-systemd-service-unit-in-linux
ExecStart will be the startup java -jar app.jar and ExecStop will be the stopping command java -jar app-stopper.jar
I have a Spring MVC application that runs with the normal SpringApplication.run(Application.class, args); statement. When I run it and then close the terminal window, it kills the process. How can I prevent it from shutting down when I close the terminal window?
I'm using OSX 10.9, Mavericks.
Thank you very much.
As Dave Syer says, you're best to use the nohup command which will prevent the child process from hanging up when the terminal window closes.
For example:
nohup java -jar name.jar 2>&1 >output.log &
That will send both the standard out and standard error to the output.log file. You can omit the >output.log and nohup will use the default log file called nohup.out.
I have a java program acting as a Network server. Thanks the the utility update-rc.d I have installed a service on a Debian / Unix server in order to have it running all the time without being connected during a SSH session.
Because my program is in java bytecode, and not a native unix executable, I have used the following tutorial to make it work as a daemon: java as a daemon service
The problem is that I don't see the output of the program any more. I need to see the output of the program, as it shows a stack trace when an exception happens. How to redirect standard and error output streams to a log file ?
Alternative question: How to run the java program and have it continusly running even when I log out from SSH ?
You can wrap the app launch command into a shell script and redirect output there:
/usr/bin/java -jar app.jar >> /var/log/app/app.log 2>&1
But I'd recommend to use some logging framework to gain more control over log files. Something like slf4j with logback or any other backend.
Alternative question: How to run the java program and have it continusly running even when I log out from SSH ?
You can do this with screen:
screen java -jar app.jar ...
Then after SSH login run
screen -r
to resume screen session.
We have a jboss application server running a webapp. We need to implement a "restart" button somewhere in the UI that causes the entire application server to restart. Our naive implementation was to call our /etc/init.d script with the restart command. This shuts down our application server then restarts it.
However, it appears that when the java process shuts down, the child process running the restart scripts dies as well, before getting to the point in the script where it starts the app server again.
We tried variations on adding '&' to the places where scripts are called, but that didn't help. Is there some where to fire the script and die without killing the script process?
Try using the nohup command to run something from within the script that you execute via Java. That is, if the script that you execute from Java currently runs this:
/etc/init.d/myservice restart
then change it to do this:
nohup /etc/init.d/myservice restart
Also, ensure that you DO NOT have stdin, stdout, or stderr being intercepted by the Java process. This could cause problems, potentially. Thus, maybe try this (assuming bash or sh):
nohup /etc/init.d/myservice restart >/dev/null 2>&1
Set your signal handlers in the restart script to ignore your signal with trap:
trap "" 2 # ignore SIGINT
trap "" 15 # ignore SIGTERM
After doing this, you'll need to kill your restart script with some other signal when needed, probably SIGKILL.