Develop Reference

How do I launch a service on linux? [duplicate]

I have written a Java server application that runs on a standard virtual hosted Linux solution. The application runs all the time listening for socket connections and creating new handlers for them. It is a server side implementation to a client-server application.
The way I start it is by including it in the start up rc.local script of the server. However once started I do not know how to access it to stop it and if I want to install an update, so I have to restart the server in order to restart the application.
On a windows PC, for this type of application I might create a windows service and then I can stop and start it as I want. Is there anything like that on a Linux box so that if I start this application I can stop it and restart it without doing a complete restart of the server.
My application is called WebServer.exe. It is started on server startup by including it in my rc.local as such:
java -jar /var/www/vhosts/myweb.com/phpserv/WebServer.jar &
I am a bit of a noob at Linux so any example would be appreciated with any posts. However I do have SSH, and full FTP access to the box to install any updates as well as access to a Plesk panel.

I wrote another simple wrapper here:
#!/bin/sh
SERVICE_NAME=MyService
PATH_TO_JAR=/usr/local/MyProject/MyJar.jar
PID_PATH_NAME=/tmp/MyService-pid
case $1 in
start)
echo "Starting $SERVICE_NAME ..."
if [ ! -f $PID_PATH_NAME ]; then
nohup java -jar $PATH_TO_JAR /tmp 2>> /dev/null >> /dev/null &
echo $! > $PID_PATH_NAME
echo "$SERVICE_NAME started ..."
else
echo "$SERVICE_NAME is already running ..."
fi
;;
stop)
if [ -f $PID_PATH_NAME ]; then
PID=$(cat $PID_PATH_NAME);
echo "$SERVICE_NAME stoping ..."
kill $PID;
echo "$SERVICE_NAME stopped ..."
rm $PID_PATH_NAME
else
echo "$SERVICE_NAME is not running ..."
fi
;;
restart)
if [ -f $PID_PATH_NAME ]; then
PID=$(cat $PID_PATH_NAME);
echo "$SERVICE_NAME stopping ...";
kill $PID;
echo "$SERVICE_NAME stopped ...";
rm $PID_PATH_NAME
echo "$SERVICE_NAME starting ..."
nohup java -jar $PATH_TO_JAR /tmp 2>> /dev/null >> /dev/null &
echo $! > $PID_PATH_NAME
echo "$SERVICE_NAME started ..."
else
echo "$SERVICE_NAME is not running ..."
fi
;;
esac
You can follow a full tutorial for init.d here and for systemd (ubuntu 16+) here
If you need the output log replace the 2
nohup java -jar $PATH_TO_JAR /tmp 2>> /dev/null >> /dev/null &
lines for
nohup java -jar $PATH_TO_JAR >> myService.out 2>&1&

A simple solution is to create a script start.sh that runs Java through nohup and then stores the PID to a file:
nohup java -jar myapplication.jar > log.txt 2> errors.txt < /dev/null &
PID=$!
echo $PID > pid.txt
Then your stop script stop.sh would read the PID from the file and kill the application:
PID=$(cat pid.txt)
kill $PID
Of course I've left out some details, like checking whether the process exists and removing pid.txt if you're done.

Linux service init script are stored into /etc/init.d. You can copy and customize /etc/init.d/skeleton file, and then call
service [yourservice] start|stop|restart
see http://www.ralfebert.de/blog/java/debian_daemon/. Its for Debian (so, Ubuntu as well) but fit more distribution.

Maybe not the best dev-ops solution, but good for the general use of a server for a lan party or similar.
Use screen to run your server in and then detach before logging out, this will keep the process running, you can then re-attach at any point.
Workflow:
Start a screen: screen
Start your server: java -jar minecraft-server.jar
Detach by pressing: Ctl-a, d
Re-attach: screen -r
More info here: https://www.gnu.org/software/screen/manual/screen.html

Another alternative, which is also quite popular is the Java Service Wrapper. This is also quite popular around the OSS community.

Referring to Spring Boot application as a Service as well, I would go for the systemd version, since it's the easiest, least verbose, and best integrated into modern distros (and even the not-so-modern ones like CentOS 7.x).

The easiest way is to use supervisord. Please see full details here: http://supervisord.org/
More info:
https://askubuntu.com/questions/779830/running-an-executable-jar-file-when-the-system-starts/852485#852485
https://www.digitalocean.com/community/tutorials/how-to-install-and-manage-supervisor-on-ubuntu-and-debian-vps

Here is a sample shell script (make sure you replace the MATH name with the name of the your application):
#!/bin/bash
### BEGIN INIT INFO
# Provides: MATH
# Required-Start: $java
# Required-Stop: $java
# Short-Description: Start and stop MATH service.
# Description: -
# Date-Creation: -
# Date-Last-Modification: -
# Author: -
### END INIT INFO
# Variables
PGREP=/usr/bin/pgrep
JAVA=/usr/bin/java
ZERO=0
# Start the MATH
start() {
echo "Starting MATH..."
#Verify if the service is running
$PGREP -f MATH > /dev/null
VERIFIER=$?
if [ $ZERO = $VERIFIER ]
then
echo "The service is already running"
else
#Run the jar file MATH service
$JAVA -jar /opt/MATH/MATH.jar > /dev/null 2>&1 &
#sleep time before the service verification
sleep 10
#Verify if the service is running
$PGREP -f MATH > /dev/null
VERIFIER=$?
if [ $ZERO = $VERIFIER ]
then
echo "Service was successfully started"
else
echo "Failed to start service"
fi
fi
echo
}
# Stop the MATH
stop() {
echo "Stopping MATH..."
#Verify if the service is running
$PGREP -f MATH > /dev/null
VERIFIER=$?
if [ $ZERO = $VERIFIER ]
then
#Kill the pid of java with the service name
kill -9 $($PGREP -f MATH)
#Sleep time before the service verification
sleep 10
#Verify if the service is running
$PGREP -f MATH > /dev/null
VERIFIER=$?
if [ $ZERO = $VERIFIER ]
then
echo "Failed to stop service"
else
echo "Service was successfully stopped"
fi
else
echo "The service is already stopped"
fi
echo
}
# Verify the status of MATH
status() {
echo "Checking status of MATH..."
#Verify if the service is running
$PGREP -f MATH > /dev/null
VERIFIER=$?
if [ $ZERO = $VERIFIER ]
then
echo "Service is running"
else
echo "Service is stopped"
fi
echo
}
# Main logic
case "$1" in
start)
start
;;
stop)
stop
;;
status)
status
;;
restart|reload)
stop
start
;;
*)
echo $"Usage: $0 {start|stop|status|restart|reload}"
exit 1
esac
exit 0

From Spring Boot application as a Service, I can recommend the Python-based supervisord application. See that stack overflow question for more information. It's really straightforward to set up.

Other answers do a good job giving custom scripts and setups depending on your platform. In addition to those, here are the mature, special purpose programs that I know of:
JSW from TanukiSoftware
YAJSW is an open source clone from the above. It is written in Java, and it is a nanny process that manages the child process (your code) according to configurations. Works on windows / linux.
JSVC is a native application. Its also a nanny process, but it invokes your child application through the JNI, rather than as a subprocess.

You can use Thrift server or JMX to communicate with your Java service.

From Spring Boot Reference Guide
Installation as an init.d service (System V)
Simply symlink the jar to init.d to support the standard start, stop, restart and status commands.
Assuming that you have a Spring Boot application installed in /var/myapp, to install a Spring Boot application as an init.d service simply create a symlink:
$ sudo ln -s /var/myapp/myapp.jar /etc/init.d/myapp
Once installed, you can start and stop the service in the usual way. For example, on a Debian based system:
$ service myapp start
If your application fails to start, check the log file written to /var/log/<appname>.log for errors.
Continue reading to know how to secure a deployed service.
After doing as written I've discovered that my service fails to start with this error message in logs: start-stop-daemon: unrecognized option --no-close. And I've managed to fix it by creating a config file /var/myapp/myapp.conf with the following content
USE_START_STOP_DAEMON=false

It is possible to run the war as a Linux service, and you may want to force in your pom.xml file before packaging, as some distros may not recognize in auto mode. To do it, add the following property inside of spring-boot-maven-plugin plugin.
<embeddedLaunchScriptProperties>
<mode>service</mode>
</embeddedLaunchScriptProperties>
Next, setup your init.d with:
ln -s myapp.war /etc/init.d/myapp
and you will be able to run
service myapp start|stop|restart
There are many other options that you can find in Spring Boot documentation, including Windows service.

Im having Netty java application and I want to run it as a service with systemd. Unfortunately application stops no matter of what Type I'm using. At the end I've wrapped java start in screen. Here are the config files:
service
[Unit]
Description=Netty service
After=network.target
[Service]
User=user
Type=forking
WorkingDirectory=/home/user/app
ExecStart=/home/user/app/start.sh
TimeoutStopSec=10
Restart=on-failure
RestartSec=5
[Install]
WantedBy=multi-user.target
start
#!/bin/sh
/usr/bin/screen -L -dmS netty_app java -cp app.jar classPath
from that point you can use systemctl [start|stop|status] service.

To run Java code as daemon (service) you can write JNI based stub.
http://jnicookbook.owsiak.org/recipe-no-022/
for a sample code that is based on JNI. In this case you daemonize the code that was started as Java and main loop is executed in C. But it is also possible to put main, daemon's, service loop inside Java.
https://github.com/mkowsiak/jnicookbook/tree/master/recipes/recipeNo029
Have fun with JNI!

However once started I don't know how to access it to stop it
You can write a simple stop script that greps for your java process, extracts the PID and calls kill on it. It's not fancy, but it's straight forward.
Something like that may be of help as a start:
#!/bin/bash
PID = ps ax | grep "name of your app" | cut -d ' ' -f 1
kill $PID

Check and run/restart processes, bash [duplicate]

This question already has answers here:
Linux Script to check if process is running and act on the result
(8 answers)
Closed 5 years ago.
I wrote a bash-script to check if a process is running. It doesn't work since the ps command always returns exit code 1. When I run the ps command from the command-line, the $? is correctly set, but within the script it is always 1. Any idea?
#!/bin/bash
SERVICE=$1
ps -a | grep -v grep | grep $1 > /dev/null
result=$?
echo "exit code: ${result}"
if [ "${result}" -eq "0" ] ; then
echo "`date`: $SERVICE service running, everything is fine"
else
echo "`date`: $SERVICE is not running"
fi
Bash version: GNU bash, version 3.2.25(1)-release (x86_64-redhat-linux-gnu)

There are a few really simple methods:
pgrep procname && echo Running
pgrep procname || echo Not running
killall -q -0 procname && echo Running
pidof procname && echo Running

This trick works for me. Hope this could help you. Let's save the followings as checkRunningProcess.sh
#!/bin/bash
ps_out=`ps -ef | grep $1 | grep -v 'grep' | grep -v $0`
result=$(echo $ps_out | grep "$1")
if [[ "$result" != "" ]];then
echo "Running"
else
echo "Not Running"
fi
Make the checkRunningProcess.sh executable.And then use it.
Example to use.
20:10 $ checkRunningProcess.sh proxy.py
Running
20:12 $ checkRunningProcess.sh abcdef
Not Running

I tried your version on BASH version 3.2.29, worked fine. However, you could do something like the above suggested, an example here:
#!/bin/sh
SERVICE="$1"
RESULT=`ps -ef | grep $1 | grep -v 'grep' | grep -v $0`
result=$(echo $ps_out | grep "$1")
if [[ "$result" != "" ]];then
echo "Running"
else
echo "Not Running"
fi

I use this one to check every 10 seconds process is running and start if not and allows multiple arguments:
#!/bin/sh
PROCESS="$1"
PROCANDARGS=$*
while :
do
RESULT=`pgrep ${PROCESS}`
if [ "${RESULT:-null}" = null ]; then
echo "${PROCESS} not running, starting "$PROCANDARGS
$PROCANDARGS &
else
echo "running"
fi
sleep 10
done

Check if your scripts name doesn't contain $SERVICE. If it does, it will be shown in ps results, causing script to always think that service is running. You can grep it against current filename like this:
#!/bin/sh
SERVICE=$1
if ps ax | grep -v grep | grep -v $0 | grep $SERVICE > /dev/null
then
echo "$SERVICE service running, everything is fine"
else
echo "$SERVICE is not running"
fi

Working one.
!/bin/bash
CHECK=$0
SERVICE=$1
DATE=`date`
OUTPUT=$(ps aux | grep -v grep | grep -v $CHECK |grep $1)
echo $OUTPUT
if [ "${#OUTPUT}" -gt 0 ] ;
then echo "$DATE: $SERVICE service running, everything is fine"
else echo "$DATE: $SERVICE is not running"
fi

Despite some success with the /dev/null approach in bash. When I pushed the solution to cron it failed. Checking the size of a returned command worked perfectly though. The ampersrand allows bash to exit.
#!/bin/bash
SERVICE=/path/to/my/service
result=$(ps ax|grep -v grep|grep $SERVICE)
echo ${#result}
if ${#result}> 0
then
echo " Working!"
else
echo "Not Working.....Restarting"
/usr/bin/xvfb-run -a /opt/python27/bin/python2.7 SERVICE &
fi

#!/bin/bash
ps axho comm| grep $1 > /dev/null
result=$?
echo "exit code: ${result}"
if [ "${result}" -eq "0" ] ; then
echo "`date`: $SERVICE service running, everything is fine"
else
echo "`date`: $SERVICE is not running"
/etc/init.d/$1 restart
fi
Something like this

Those are helpful hints. I just needed to know if a service was running when I started the script, so I could leave the service in the same state when I left. I ended up using this:
HTTPDSERVICE=$(ps -A | grep httpd | head -1)
[ -z "$HTTPDSERVICE" ] && echo "No apache service running."

I found the problem. ps -ae instead ps -a works.
I guess it has to do with my rights in the shared hosting environment. There's apparently a difference between executing "ps -a" from the command line and executing it from within a bash-script.

A simple script version of one of Andor's above suggestions:
!/bin/bash
pgrep $1 && echo Running
If the above script is called test.sh then, in order to test, type:
test.sh NameOfProcessToCheck
e.g.
test.sh php

I was wondering if it would be a good idea to have progressive attempts at a process, so you pass this func a process name func_terminate_process "firefox" and it tires things more nicely first, then moves on to kill.
# -- NICE: try to use killall to stop process(s)
killall ${1} > /dev/null 2>&1 ;sleep 10
# -- if we do not see the process, just end the function
pgrep ${1} > /dev/null 2>&1 || return
# -- UGLY: Step trough every pid and use kill -9 on them individually
for PID in $(pidof ${1}) ;do
echo "Terminating Process: [${1}], PID [${PID}]"
kill -9 ${PID} ;sleep 10
# -- NASTY: If kill -9 fails, try SIGTERM on PID
if ps -p ${PID} > /dev/null ;then
echo "${PID} is still running, forcefully terminating with SIGTERM"
kill -SIGTERM ${PID} ;sleep 10
fi
done
# -- If after all that, we still see the process, report that to the screen.
pgrep ${1} > /dev/null 2>&1 && echo "Error, unable to terminate all or any of [${1}]" || echo "Terminate process [${1}] : SUCCESSFUL"

I need to do this from time to time and end up hacking the command line until it works.
For example, here I want to see if I have any SSH connections, (the 8th column returned by "ps" is the running "path-to-procname" and is filtered by "awk":
ps | awk -e '{ print $8 }' | grep ssh | sed -e 's/.*\///g'
Then I put it in a shell-script, ("eval"-ing the command line inside of backticks), like this:
#!/bin/bash
VNC_STRING=`ps | awk -e '{ print $8 }' | grep vnc | sed -e 's/.*\///g'`
if [ ! -z "$VNC_STRING" ]; then
echo "The VNC STRING is not empty, therefore your process is running."
fi
The "sed" part trims the path to the exact token and might not be necessary for your needs.
Here's my example I used to get your answer. I wrote it to automatically create 2 SSH tunnels and launch a VNC client for each.
I run it from my Cygwin shell to do admin to my backend from my windows workstation, so I can jump to UNIX/LINUX-land with one command, (this also assumes the client rsa keys have already been "ssh-copy-id"-ed and are known to the remote host).
It's idempotent in that each proc/command only fires when their $VAR eval's to an empty string.
It appends " | wc -l" to store the number of running procs that match, (i.e., number of lines found), instead of proc-name for each $VAR to suit my needs. I keep the "echo" statements so I can re-run and diagnose the state of both connections.
#!/bin/bash
SSH_COUNT=`eval ps | awk -e '{ print $8 }' | grep ssh | sed -e 's/.*\///g' | wc -l`
VNC_COUNT=`eval ps | awk -e '{ print $8 }' | grep vnc | sed -e 's/.*\///g' | wc -l`
if [ $SSH_COUNT = "2" ]; then
echo "There are already 2 SSH tunnels."
elif [ $SSH_COUNT = "1" ]; then
echo "There is only 1 SSH tunnel."
elif [ $SSH_COUNT = "0" ]; then
echo "connecting 2 SSH tunnels."
ssh -L 5901:localhost:5901 -f -l USER1 HOST1 sleep 10;
ssh -L 5904:localhost:5904 -f -l USER2 HOST2 sleep 10;
fi
if [ $VNC_COUNT = "2" ]; then
echo "There are already 2 VNC sessions."
elif [ $VNC_COUNT = "1" ]; then
echo "There is only 1 VNC session."
elif [ $VNC_COUNT = "0" ]; then
echo "launching 2 vnc sessions."
vncviewer.exe localhost:1 &
vncviewer.exe localhost:4 &
fi
This is very perl-like to me and possibly more unix utils than true shell scripting. I know there are lots of "MAGIC" numbers and cheezy hard-coded values but it works, (I think I'm also in poor taste for using so much UPPERCASE too). Flexibility can be added with some cmd-line args to make this more versatile but I wanted to share what worked for me. Please improve and share. Cheers.

A solution with service and awk that takes in a comma-delimited list of service names.
First it's probably a good bet you'll need root privileges to do what you want. If you don't need to check then you can remove that part.
#!/usr/bin/env bash
# First parameter is a comma-delimited string of service names i.e. service1,service2,service3
SERVICES=$1
ALL_SERVICES_STARTED=true
if [ $EUID -ne 0 ]; then
if [ "$(id -u)" != "0" ]; then
echo "root privileges are required" 1>&2
exit 1
fi
exit 1
fi
for service in ${SERVICES//,/ }
do
STATUS=$(service ${service} status | awk '{print $2}')
if [ "${STATUS}" != "started" ]; then
echo "${service} not started"
ALL_SERVICES_STARTED=false
fi
done
if ${ALL_SERVICES_STARTED} ; then
echo "All services started"
exit 0
else
echo "Check Failed"
exit 1
fi

The most simple check by process name :
bash -c 'checkproc ssh.exe ; while [ $? -eq 0 ] ; do echo "proc running";sleep 10; checkproc ssh.exe; done'

Shell script. How to kill java process and then start it again with nohup

I'm trying to do it like this:
file_name=$1
#Clear log file
echo > nohup.out
for PID in $(ps aux | grep service_name | awk {'print $2'}); do
kill -9 $PID;
done
echo "Killed old process"
nohup java -Xms256m -Xmx256m -XX:MaxMetaspaceSize=256m -jar $file_name &
echo "Started new process"
But it's just printing "Killed" and doesn't start it again.
If I do all this stuff separately - it's working, but for all together - not...
Допоможіть хто зможе...

The script from which you execute it, does it contain "service_name" in its name? Then it obviously fulfills the criteria for begin killed by your for loop and commits suicide.
If it does not, then still the grep service_name remains which fulfills the kill criteria (has service_name in its cmd line) - for fixed strings in grep I usually write them grep "s[e]rvice_name", other prefer to put another |grep -v grep into the pipe before the awk

Monitoring Java-Runtime / Virgo Server with Shell Script

I am trying to create a script that monitors a java runtime process,which makes use of a Virgo service. It should start the process when its not running. As there is no specific service name, i was thinking of grepping the name of the process and use it as an identifier.
Here is the code i thought of:
#!/bin/sh
service=virgo
ps auxw | grep $service | grep -v grep > /dev/null
if [ $? != 0 ]
then
/opt/apromore/ApromoreCode/build.xml start-virgo > /dev/null
else
echo Apromore is running already
fi
and this is the process I try to monitor (value from ps aux)
/usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java -classpath usr/share/ant/lib/ant-launcher.jar:/ usr/share/java/xmlParserAPIs.jar:/usr/share/java/xercesImpl.jar -Dant.home=/usr/ share/ant -Dant.library.dir=/usr/share/ant/lib org.apache.tools.ant.launch.Launc her -cp start-virgo
but even when the process is running, i cant identify it with the mentioned script. There is a error called $'\r'. I have no idea how to get rid of it.

Check if jar running from shell

I have a java jar program that I am trying to run on startup of my machine. Ideally, the shells script will check every 60 seconds to assure that the jar is running. How do I check if the jar is running on centos, this does not appear to be working?
My current .sh file:
#!/bin/bash
while [ true ]
do
cnt=`ps -eaflc --sort stime | grep /home/Portal.jar |grep -v grep | wc -l`
if(test $cnt -eq 3);
then
echo "Service already running..."
else
echo "Starting Service"
java -jar /home/Portal.jar >> /dev/null &
fi
sleep 1m
done
I used this for referencing so far.

Depending on what your program does, there may be more or less intelligent ways to check it. For example, if you have some server, it will listen on a port.
Then something like
netstat -an | fgrep tcp | fgrep LISTEN | fgrep :87654 # or whatever your port is
could do the job.
Then there is lsof, which could also detect listening ports.
Finally, you could connect and issue a pseudo request. For example, for a http server, you could use lynx or curl. For a server with a non-stamdard protocol, you can write a small client program whose sole purpose is to connect to the server just to see if it is there.

Store your process id in file and check for this process.
#!/bin/bash
while [ true ]
do
pid=$(cat /tmp/portal.pid)
if [[ -n "$pid" && $(ps -p $pid | wc -l) -eq 2 ]]
then
echo "Service already running..."
else
echo "Starting Service"
java -jar /home/Portal.jar >> /dev/null &
echo $! > /tmp/portal.pid
fi
sleep 1m
done
/tmp will be cleared on restart, all right in this case.

I did the very same scenario a couple of months ago. My task was to ensure a jar distributed java program to run 24/7 on a Linux server.
My program was console-based, started, did something then stopped.
I did a shell script that started, waited to end and then re-started the app in an infinite loop.
I installed runit, created a service and supplied this script as the run script. Works very well.
In general, the shell script ensures that the java program is running and runit ensures that the start script (which is our script) is running.
You find valuable info here: http://smarden.org/runit/faq.html

Rather than putting the process to sleep , I'd rather have it exit and use crontab to run the process every 1 min;which will check if its running or else just stop the script.
#!/bin/sh
declare -a devId=( "/Path/To/TestJar.jar Test1" "/Path/To/TestJar.jar Test2" ) #jarfile with pathname and Test as argument
# get length of an array
arraylength=${#devId[#]}
# use for loop to read all values and indexes
for (( i=1; i<${arraylength}+1; i++ ));
do
y=${devId[$i-1]}
cnt=`ps -eaflc --sort stime | grep "$y" |grep -v grep | wc -l`
if [ $cnt = 0 ]
then
java -jar $y& > /dev/null
b=$(basename $y)
echo $b
#DO SOME OPERATION LIKE SEND AN EMAIL OR ADD TO LOG FILE
continue
elif [ $cnt != 0 ]
then
echo 'do nothing'
fi
done

Why do you think $cnt should be equal to 3? Shouldn't it be equal to 1 if the process is already running?

You could use the jps command. It return the JVMs running in the system.

I created following script to monitor my application jar is running or not.
In this case My application jar is running on port 8080
#!/bin/bash
check=$(netstat -an | grep 8080 | wc -l)
if [[ $check -eq 0 ]];then
echo "jar is not running..."
/usr/bin/java -jar /path/to/target/application.jar >> /dev/null &
else
echo "it is running"
fi
I am using cronjob to monitor jar app by executing shell script on every minute.
$ crontab -e
in the end of file
* * * * * /bin/bash monitor-jar.sh /dev/null 2>&1